Abstract
This thesis explores the relevance of CLT for high school biology teaching and how PBL can help reduce cognitive load. Existing literature shows that effective application of PBL theory results to students following the teachers’ thinking, respond positively to the teacher, and make the classroom atmosphere active. This thesis conducted an experiment on 625 students and 10 teachers from Lushan Gate Fire Squadron School in Nanning City, China. The students were divided into two groups: experimental group and control group. After the high school biology teachers adopted the CLT teaching approach, the students proved to be more active in their classes. They knew the focus of their study better and learnt more attentively. Students’ attentiveness in biological learning increased, they invested more time and became more active. After 14 weeks of use, the experimental class scored higher than the control class in a biology exam. Learners became more active, enthusiastic, and fascinated in learning biology. They actively participated in learning, actively cooperated with teachers and steadily completed learning tasks. The thesis also applied a self-rating scale to measure the cognitive load of students after the experiment. The results showed that learners’ psychological pressure in the experimental class had been reduced. The difficulty of learning materials was reduced to a certain extent. The thesis concluded by recommending that (i) scholars should timely take note of the cognitive structure of students and the development changes of their cognitive structure, (ii) application of CLT to concept teaching needs to be combined with other teaching methods, (iii) students should be the focus in teaching to improve initiative of students in learning. Therefore, this thesis asserts that the core of PBL teaching mode is autonomous learning and autonomous development and for self-learning and self-development to be achieved, we must start to reform teaching concepts.
Keywords: Cognitive Load Theory; Empirical Research; PBL; Science teaching
1.1 Reasons for choosing the topic
With the advancement of the new curriculum reform, educators are paying more attention to the students’ dominant position in learning. “Learner-centred design orientation focuses on how to help people learn more effectively and improve human cognitive ability through technology”. In this case, teachers must follow the law of students’ cognitive development, pay attention to students’ understanding, thinking, feeling, and activities in the learning process, promote students’ learning and achieve new knowledge through effective teaching design.
The new curriculum reform in full swing has inspired many educators to explore how to change the traditional teaching mode and improve the efficiency of biology classroom teaching and achieve certain results. However, high school students’ learning state of biology is not optimistic. Many students complain that biology is so difficult to understand. There are not only a lot of concepts memorized by liberal arts but also a lot of reasoning calculation and experimental exploration of science. One of the reasons is that many teachers only consider how to thoroughly explain the knowledge, organize a variety of teaching activities to activate the classroom atmosphere, and make exquisite PPT to attract students’ attention. However, they seldom consider whether such teaching design increases the cognitive load of students. Due to the lack of enough attention to the cognitive factors of learners, many teaching activities deviate from the “learner-centred” teaching premise, thus forming an embarrassing situation of “teachers are tired of teaching, students are tired of learning.”
Cognitive load is an important factor that cannot be ignored in the process of learning. “It refers to the total amount of psychological resources that people need in the process of information processing.” In the 1980s, a cognitive psychology expert at the University of New South Wales, Australia, John Sweller first proposed cognitive load theory (CLT). According to the theory, learners’ cognitive resources are limited. The allocation of resources follows the principle of “this is more than that is less, and the total amount remains unchanged.” That is to say if learners engage in several learning activities at the same time, and the cognitive resources consumed by these activities exceed the total amount of cognitive resources, cognitive overload will occur. In this case, even if the resources provided are minimal, rich and diversified information presentations cannot effectively promote learners’ learning activities.
At present, the new curriculum reform has reached the bottleneck stage. How to consolidate the achievements, break through the development bottleneck as soon as possible, and expand the achievements? The author believes that it is an important reform idea to study the cognitive load theory and apply it to specific subjects’ teaching. High school biology teaching should follow the human brain’s cognitive law, pay attention to the different cognitive load components of different levels of students in different stages of learning, analyse its causes and effects, and then design teaching activities based on this. Only in this way can we use students’ limited cognitive resources as much as possible in their “proximal development area” of learning and truly realize “burden reduction and efficiency increase.”
With human society’s development and the emergence of modern information technology, we have entered a new information age. Information technology not only extends human brain function, expands human intelligence, greatly enhances human ability to understand and transform the world, but also penetrates and influences all fields of human society, including education. As a modern teaching method, multimedia has brought revolutionary changes to the traditional teaching methods and has great advantages compared to traditional teaching. In biology teaching, it is very common for teachers to use multimedia to assist teaching. According to the author’s investigation, in recent years, most middle schools in Suzhou City have equipped teachers with multimedia teaching equipment, encouraging teachers to combine modern educational means with traditional teaching, which greatly promotes the reform of biology teaching and improves the teaching effect of teachers to a certain extent. It enhances students’ learning enthusiasm and cultivates their interest in learning. Multimedia software can combine many kinds of information elements, such as words, graphics, images, sounds, animations, videos, and so on so that learners can obtain multi-channel teaching information and better memorize the acquired knowledge and skills. However, to carry out scientific and reasonable multimedia teaching presentation, we should not rely solely on subjective experience and aesthetic requirements but should carry out presentations under the guidance of scientific design principles to play a role in promoting students’ learning.
In exploring how to design effective multimedia learning environment principles, two independent research clues are the most important, and they have obtained extremely important achievements. The first is the cognitive load theory proposed by Australian instructional design research expert John Sweller (J) and the research on the promotion and application of multimedia teaching in multimedia teaching together with Clark (R.C.). The second is the cognitive theory of multimedia learning proposed by American educational psychologist and multimedia teaching expert Mayer (R.E). The common point of cognitive load theory and multimedia learning cognitive theory is to provide the theoretical basis of courseware design for multimedia teaching. It also strives to make the presentation of teaching materials reduce the external cognitive load to the maximum extent so that students can allocate work memory resources in the learning process, to carry out classroom teaching effectively.
According to the author’s questionnaire survey in several senior high schools, multimedia teaching has been very common in middle school biology classroom teaching. Most teachers and students have accepted such a convenient, intuitive, and vivid teaching method without any objection. However, the questionnaire survey results also reflect some problems contrary to the theory in the current high school biology multimedia teaching. Under the guidance of the two theories, multimedia design is the ideal condition of multimedia teaching, but it cannot be fully realized at present because there are some misunderstandings in multimedia assisted teaching, which affects the organic integration of biology teaching and information technology. Meaningful learning requires learners to carry out a large amount of cognitive processing during learning, but learners’ cognitive processing capacity is very limited. How to organize the presentation of multimedia information so that learners’ total cognitive load does not exceed the limit of their WM capacity is the key to the design of multimedia courseware. In practice, multimedia courseware designers often ignore the limited WM capacity, thinking that the richer the representation of multimedia information, the better. In fact, the bad combination of multimedia information will increase the unnecessary cognitive load and hinder learners’ effective learning. According to the author’s data, there are few empirical studies on cognitive load from the perspective of specific disciplines, especially in biology, which provides a certain space and platform for the research of this topic.
Simultaneously, problem-based learning (PBL) is a direct way to cultivate problem-solving ability. It is of great significance to take various measures to improve the effect and efficiency of PBL. PBL based on network is mainly for students to acquire new knowledge and skills by solving real problems, and they need to pay more cognitive efforts in the learning process. In practice, students are often drowned in the information coming from their faces. They are at a loss in the face of complex problems and even can’t bear the burden to give up their inquiry activities. Most of the time, students are busy searching for information and simply pasting and combining materials on the Internet, so they can’t think deeply and put forward their own independent opinions. It can be seen that heavy cognitive load may be an important factor affecting the effect of PBL. Therefore, taking measures to reduce the cognitive load in network PBL is an important guarantee for its smooth and effective implementation. Although PBL in network environment has its own advantages, it also inevitably has defects. In the literature research and research, the author found that there are some problems in the implementation of PBL under the network environment, such as students are distracted by the temptation of non-learning information in the network; or they are frustrated in the exploration and lose interest in learning; even in the process of solving problems, they feel the pressure of learning and can’t bear the burden to give up learning. These problems make the implementation of PBL in the network environment difficult and often make the front-line teachers “stay away” and hinder the wide application of PBL. This study analyses the negative effects of PBL on the individual cognitive systems from the perspective of cognitive load, puts forward preventive measures to provide a strategic reference for the design of e-learning environment and contributes to the enrichment of instructional design theory.
1.2 The significance of this topic
At present, many theoretical studies have pointed out that the advantages and disadvantages of multimedia teaching are parallel in practical work, and even the “defects” have covered the “Yu.” In addition, the results of the questionnaire survey conducted by the author can reflect that many teachers and students have not adapted to the unreasonable teaching design in the current high school biology multimedia teaching, and even feel disgusted about it. Because of the huge amount of information displayed in the multimedia courseware it has little effect in the teaching work and has a negative impact – students not only cannot learn knowledge but also lose interest in learning.
According to the relevant information about the application of cognitive load in mathematics, English, physics, and other disciplines, we can find that this is still a newly reclaimed area. Cognitive load is closely related to instructional design and learning performance. In the process of teaching, if the cognitive load is too low, it will cause time waste; if the cognitive load is too high, it will hinder the information processing activities of learners. The ideal mode of teaching is that learners can work full load. Therefore, the instructional design aims to help learners carry out learning activities smoothly to acquire the most knowledge with the least psychological resources. Therefore, some scholars use the cognitive load theory to guide the design of mathematical teaching examples to reduce the unnecessary cognitive load. ① Other scholars use the cognitive load theory to explore how to reduce the cognitive load in the design of English multimedia courseware, promote learning, ② or further apply the cognitive load theory to the mind map for English teaching。 ③ However, these studies are theoretical expansion, extension, or application; empirical research is very few, especially in high school biology multimedia teaching. Empirical research on cognitive load theory is rare; therefore, this study’s primary significance is to fill in the research content in this field.
This thesis is an empirical study based on the sample of middle school students in Suzhou area. First, based on the literature research, it carries on the research and discussion from the theoretical aspect. From the practical point of view, to investigate the cognitive load of middle school students in different multimedia presentation modes, provide a theoretical basis for secondary school educators in teaching design, and design a more effective teaching method. According to the cognitive load theory and the cognitive theory of multimedia learning, teaching courseware can make multimedia technology play a more significant role in classroom teaching. Therefore, it will be a very meaningful topic in the research of middle school biology education.
In short, the theoretical significance of this study: the cognitive load theory and multimedia learning cognitive theory are elaborated and expanded in detail, and the guiding significance of the two theories to the specific teaching work is clarified, which enriches the application scope of cognitive load theory and the research scope of multimedia teaching of high school biology.
Practical significance: through a semester of specific teaching practice, the theory is combined with practice. The related problems of multimedia teaching of biology in middle school are effectively improved, which provides reference and Enlightenment for biological educators.
1.3 Research ideas and methods
This thesis is divided into five chapters. The first chapter is the introduction, which mainly introduces the reasons for the topic selection, summarizes the research status at home and abroad, and explains the research ideas and methods, possible innovation, and shortcomings. The second chapter outlines the connotation, theoretical basis, teaching effect, types, measurement methods of cognitive load theory, and discusses the Enlightenment of its combination with senior high school biology teaching. The third chapter investigates and analyses teachers’ and students’ current cognitive load in high school biology teaching, makes descriptive statistics and analysis on the collected data, and puts forward effective teaching strategies to manage cognitive load for practical teaching. The fourth chapter is an empirical study. Under the guidance of the above strategies, teaching experiments are carried out. Specific teaching cases and experimental data are used to demonstrate the role of cognitive load theory in practical teaching, and the teaching effect is objectively evaluated. The fifth chapter is the conclusion, which summarizes the research results, and puts forward the reflection and prospect for the future.
- Literature research method. In the initial stage, we read and collate the literature, and collect the main views of domestic and foreign scholars on cognitive load theory from the theoretical and practical aspects, to pave the way for the later teaching design and research.
- Investigation and research method. Through the questionnaire survey, we can deeply understand the current situation of the cognitive load of senior high school biology teaching between teachers and students, find out the problems existing in teaching and learning, and pave the way for effective management strategies.
- Case analysis method. The analysis of high school biology teaching cases, exploring the optimization of teaching strategies and provides an empirical basis for this study.
- Quasi-experimental study. Conducted through the design of teaching cases in a high school grade and carrying out relevant experimental research. The experimental conclusion is drawn through the collection and analysis of relevant data.
- Inductive method. Summarizing the research experience and theorizing the research results.
1.4 Research innovation and deficiency
- Research innovations: at present, the theory of cognitive load has been widely valued by scholars at home and abroad and has a great influence in education and teaching. The teaching design combining it with specific subjects has also been explored preliminarily, but it is not deep enough, especially since there is almost no teaching design based on cognitive load theory. Therefore, the author explores the application of cognitive load theory in senior high school biology teaching from two angles of theory and practice, summarizes the effective strategies to manage cognitive load, and provides an empirical basis for its practical application as much as possible.
- Deficiencies. Due to the lack of references on the application of cognitive load theory in senior high school biology teaching, this study’s theoretical level needs to be further deepened. Due to the limitation of research time and funds, the quasi-experimental design adopted in this study is only implemented in a middle-aged and middle-aged school where the author works. The number of subjects affects the experiment’s validity and reliability, and its operability needs to be improved one step verification.
Cognitive load refers to the phenomenon of individuals consuming cognitive resources when learning and completing tasks. It is the total capacity of psychological activities performed by the cognitive system caused during the completion of the current task (Sweller, 1988). The integration of cognitive load theory is based on individual schema theory and individual theory of limited resources. In the form of schema theory, knowledge is gradually accumulated in the form of individual experience. When learners learn unfamiliar new knowledge, the schemata stored in long-term memory will be mobilized, compared with the current new environment, and then classified. This means that when the individual’s working memory (WM) capacity is insufficient, this processing method can make up for it. It is an automatic process that does not consume individual cognitive resources. The theory of limited resources posits that various resources (attention resources and cognitive resources) are limited. When individuals need to complete different tasks at the same time, when allocating attention resources and cognitive resources, they should allocate them according to the characteristics of tasks. There are many principles to be followed, and the implementation of this principle is based on the degree of automation of different tasks. According to the comprehensive analysis of the theory of limited resources and schema theory, cognitive load theory holds that individuals need to consume certain cognitive resources to a greater or lesser extent when learning any new knowledge or completing various tasks. However, human cognitive resources are limited, and the lack of resources will cause a cognitive load to a certain extent.
The theoretical study of cognitive load originates from the results of many studies on mental load (Holland & Tarlow, 1972). International research on mental load can be traced back to discussion on WM and long-term memory by American psychologist Miller in the 1950s (Sweller, 2010). At the end of the 1980s, Sweller, an Australian cognitive psychologist, formally put forward cognitive load as a theory, and on this basis launched a series of empirical studies (Sweller, 1994). Since the 1990s, cognitive load theory has gradually attracted attention from many scholars around the world. It has become a hot topic in the field of cognitive processing and one of the main frameworks of modern instructional design and complex problem learning (Paas, 2003; Byrne, 2012).
Sweller (1988) proposed that in receiving, collating, and applying information, learners exceed their cognitive abilities in terms of load and anxiety in respect of ‘physiology’ or ‘psychology’. This is due to the transmission process, interactive form, learning environment, and specific content of information. ‘Negative energy’ (understood metaphorically) occurs in the cognitive system. Paas and Van Merrienboer (1994, 122) maintain that ‘the load imposed on students in performing certain learning tasks is actually the degree of psychological effort consumed in them; the cognitive load is actually composed of multi-dimensional components.’ While Lai Risheng and Zeng Xiaoqing (2005, 211-218) believe that “cognitive load is the total number of corresponding intellectual behaviours that can be imposed on W.M. in some cases”. Zhao Junfeng (2011, 114) summarized it as a perception of time pressure, responsibility and learning tasks, whereas Kalyuga and Tzu-Chien Liu (2015) argued that cognitive theory consists of two main parts: (1) WM is the main part of the theory, and its processing ability and duration for dealing with unorganized and new information are very limited; (2) long-term memory (LTM) is infinite, can effectively store cognitive schemata, and can change tasks’ complexity and automation. These two components of the human cognitive structure are closely related to each other.
It is also widely accepted (Sweller, Ayres & Kalyuga, 2011) that the cognitive resources of students themselves are not unlimited. When solving complex tasks, the cognitive resources of learners will inevitably be consumed. When processing information, the cognitive resources consumed exceed the limits of students themselves, and so will produce cognitive load. In the process of teaching activities, because of the complexity of teacher selection, unreasonable instructional design, and learners’ lack of related schemata in long-term memory, cognitive load will also arise (Kalyuga and Tzu-Chien Liu, 2015).
As for the definition of cognitive load, scholars have not formed a unified understanding yet. Researchers have put forward their own understanding of cognitive load from their respective perspectives, but have expressed different views. Sweller et al. (1988) proposed that cognitive load is the total mental activity capacity applied to an individual’s cognitive system during a certain working time. Paas and Van Merrienboer (1994) pointed out that cognitive load is composed of multiple dimensions, which are applied to individuals’ cognitive systems when performing a specific task. Xin Ziqiang and Lin Chongde (2002) argue that cognitive load can be regarded as the required level of ‘mental energy’ when processing a specific amount of information; as the amount of processed information increases, the cognitive load will also increase. Lai Risheng (2005) believed that cognitive load is the total amount of intellectual activity exerted on WM under certain circumstances. Sun Chongyong and Li Shulian (2017) asserted that the total amount of cognitive resources spent on information processing in learning or task completion is the cognitive load. This thesis considers that cognitive load is the quantity of cognitive resources consumed by the W.M. system in processing and maintaining information for a specific task or learning process. From the above definitions, we can see that: (1) the generation of cognitive load often needs to be related to a specific task – if there is no specific task, learners will not manifest a cognitive load; (2) the completion of the task requires the use of limited resources in the W.M.; (3) whether the operation of the task can be carried out smoothly depends on whether there is a corresponding ‘commitment.’
2.2 Cognitive psychological basis of cognitive load theory
Cognitive load theory is the result of the development of modern cognitive psychology and is closely related to some modern cognitive theories such as schema theory, the theory of limited resources, and constructivist learning theory.
A schema is a cognitive model of knowledge. In the process of learning and mastering knowledge, knowledge is not stored in the brain in a disorderly way, but is rather linked around a specific topic according to certain rules, constituting a knowledge unit, which is a schema. A schema is a comprehensive representation of knowledge by individuals. Schema theory studies how knowledge is represented and the relationship between representation and knowledge application. Schema theory holds that a schema is an economical way to store knowledge and information. The construction of each schema is beneficial to the orderly storage of information in the LTM to realize the automation of information extraction and reduce W.M. and cognitive load.
Schema theory is one of the important theoretical bases of cognitive load theory. The concept of schema was first put forward by Kant in his works (Radford, 2005). Gestalt psychology is the first school to attach importance to the schema in modern psychological research. According to Marshall (1995), a schema is the structure or organization of actions formed according to a certain theme. The representation and storage of knowledge are generated around this theme. Generally speaking, an individual has to learn a lot of knowledge in his or her life. Units of knowledge are connected through a certain theme core, rather than stored in the brain in disorder. These interrelated units of knowledge form knowledge units through topic connection and these units form a schema. For example, in Teaching Chinese as a Foreign Language (TCFL), when a learner sees a familiar Chinese word, the learner will immediately associate the Pinyin, tone, part of speech, the meaning of the word, and word usage in a particular context. Therefore, schema theory represents a cognitive model, which is related to the construction of knowledge. How to express knowledge concretely is the main content of schema theory. Schema theory proposes that learners do not learn information passively, but rather that they actively connect new information with old information. Based on the change effect of assimilation and coordination, schemata also develop and change in the formation. Through the continuous role of assimilation, coordination and balance, a schema gradually develops from a low level to a higher level.
Schema theory holds that when a schema becomes automatic, processing capacity can be released, so that W.M. can be used to a greater extent in learners’ learning process. W.M. is then used more often, which reflects the low level of cognitive load. The theoretical basis of cognitive load theory lies within this concept. For example, when a learner is learning Chinese vocabulary, if the learner does not have the appropriate or automatic schema, he/she cannot immediately think of a schema that helps understand the vocabulary. At this time, the learner has to construct a new schema and remember all the vocabulary information points, which will cause a relatively high cognitive load. However, if there are appropriate or automated schemata, the cognitive load will be reduced, and there will be additional resources for understanding and learning.
When an individual learns new knowledge, the relevant schema stored in long-term memory will quickly and clearly classify the new knowledge according to the relevant situation. This is an automatic process without conscious control and resource consumption. In the LTM, a large amount of knowledge information is stored in the form of a schema, while in the W.M., the processing is only in the form of a unit. That is, it only takes up a small amount of storage space, which can also reduce the load in the W.M. so that the cognitive load can be reduced. All in all, schema construction can organize the information stored in long-term memory, thus reducing the WM’s workload.
2.2.2 The theory of limited resources
The resources here mainly refer to cognitive resources and attention resources, in which cognitive resources are principally manifested in the capacity of WM. The theory of resource limitation holds that cognitive resources are consumed by all kinds of cognitive activities in the process of learning, but the total amount of cognitive resources (W.M. capacity) is limited (Korbach, Brünken, & Park, 2018). Suppose people engage in multiple cognitive activities at the same time. In that case, there will be a problem of resource allocation. Suppose the total amount of cognitive resources needed in the learning process exceeds the total number of an individual’s cognitive resources. In that case, there will be a phenomenon of cognitive overload, which affects the effect and quality of learning, which is not conducive to learning. Cognitive load theory can be used to study how to use limited cognitive resources in teaching, control W.M. load, reduce cognitive load that hinders learning, and optimize the effective cognitive load that promotes learning.
The theory of limited resources is another theoretical basis of cognitive load theory, which was first proposed by American psychologist Kahneman (Bruya & Tang, 2018). The core idea of the limited theory of limited resources is that in the process of individual learning, the total amount of human cognitive resources is not infinite, and human cognitive resources are constantly consumed in various cognitive activities. When the amount of consumed cognitive resources exceeds the person’s total amount of cognitive resources, the problem of insufficient resource allocation will appear. At this time, it will appear during the learning activities; this is the so-called overload phenomenon. This phenomenon will lead to the decline of individual learning efficiency and learning quality (Matthias, 2013).
In 1956, American cognitive psychologist Miller pointed out in a famous report that short-term memory capacity is limited to 5-9 information units, which also explains that the capacity of W.M. and the resources occupied by cognition are limited. For example, suppose a learner’s cognitive resources are 50 units and that 35 units are consumed in a certain learning task, so that only 15 units are left. If there are no more than 15 cognitive resources units needed for other tasks, then learners can perform these learning tasks; if more than 15 cognitive resources are required for other tasks, then learners will not be able to carry out these learning tasks well because they have been overloaded, with an associated negative effect on learning.
According to the theory of limited resources, individual cognitive resources are not infinite, but limited. When individuals carry out cognitive activities and learning activities, their cognitive resources will be consumed, and cognitive load will be generated. Therefore, the purpose of cognitive load theory based on the theory of limited resources is to grasp the W.M. load in the teaching process, reduce the cognitive load that is not conducive to learning as much as possible, improve the cognitive load that is beneficial to learning as much as possible, and make rational and intentional use of learners’ limited cognitive resources in a certain way, to improve their learning efficiency.
2.2.3 Constructivist learning theory
Constructivist learning theory holds that learning is a process of active information construction (Jonassen, 1999). Learners are not seen as passive stimulus recipients, but as active knowledge constructors. Learners should actively select and process information to construct its meaning. The constructivist learning theory’s basic viewpoints mainly include the following principles: (1) Learners are the main body of learning. Learners have accumulated their own unique experience and propositional structure network in their lifetime and learning, which leads to different understandings of the same thing and different modes of acquisition of new knowledge. (2) Learning is a process in which learners use their own experience to actively select processes and construct meaningful internal psychological representations. In this process, learners will not only construct the meaning of existing information but also transform and reorganize the original knowledge and experience. (3) Previous knowledge and experience are the main factors affecting learning. Different learners have different knowledge experience, and they will construct knowledge and information in different ways (Jonassen, 1999).
2.3 Basic viewpoints of cognitive load theory
Cognitive load theory originates from the information processing theory of human cognition. It pays attention to the interaction between cognitive structure and external information structure and focuses on learning and teaching design based on the relationship between W.M. and LTM. Cognitive load theory has three basic assumptions:
- Limitation of the capacity of W.M. system
The W.M. system and LTM system constitute the cognitive structure that determines the psychological mechanisms of human learning. The W.M. system is the main place of information processing. Its prominent features are that the capacity and storage time of new information is extremely limited. Generally, it can only receive, process or store seven ± two blocks of information.
- The unlimited storage capacity of the long-term memory system
The LTM system can give meaning to the information processed by the W.M. and store it. It is generally believed that the capacity of the long-term memory system is, to all intents and purposes, unlimited, and that it can produce permanent records of information processed by the W.M. system. However, LTM content cannot be directly accessed by people, but must first be filtered through the W.M.
- Unlimited W.M. schema processing ability
Long-term memory information is generally stored in the form of schemata, each schema being a block or information unit encoded by thousands of information elements. When the W.M. processes new information, it is necessary to search and extract related information from the LTM, to realize the encoding of information. When information is processed consciously, many resources of the W.M. are used to search and extract related schemata. If the related schemata are applied repeatedly, automation will ensue. Furthermore, automatic schema extraction only takes up very few or possibly even no resources of the WM. At such a time, the W.M. has more resources available for processing other information. So, the ability of W.M. to process schemata is, in effect, infinite.
According to cognitive load theory, there are three types of cognitive load exerted on W.M. in information processing. They are internal cognitive load, external cognitive load and related cognitive load (Kalyuga, 2015; Sweller, 2010). Internal cognitive load refers to the cognitive load exerted on W.M. by task-related information during information processing. It depends on the degree of interaction between elements of the task material. When the elements of a task are highly interactive, they are highly related, and individuals must process these elements at the same time to make the information meaningful (Kalyuga, 2015; Sweller, 2010).
External cognitive load refers to the cognitive load exerted on the W.M. by irrelevant information in information processing. Thus, cognitive load is usually caused by improper presentation of materials. The level of external cognitive load does not affect the nature of tasks that individuals need to process at a given moment (Kalyuga, 2011; Sweller, 2010). However, the definition ofcognitive load has been controversial. Many scholars have regarded related cognitive load as an intrinsic motivation in the early stage, which refers to the cognitive load related to promoting schema construction and schema automation (Debue, 2014; Kalyuga, 2015). However, Sweller, (2011) proposed that, compared with “cognitive load,” the related cognitive load should be called “related cognitive resource.” In fact, his theoretical model does not belong to the same dimension as internal cognitive load and external cognitive load. Sweller’s theoretical model belongs to some kind of W.M. resource and is used to deal with internal cognitive load. Correspondingly, Sweller proposed that there are also “external cognitive resources” used to deal with external cognitive load in the same dimension of related cognitive resources. However, “resource” is not included in the framework of cognitive load theory (Sweller, 2011). Therefore, this study translates the term ‘related cognitive load’ into ‘relevant cognitive resource’ to avoid ambiguity. Due to the limited extent of individual W.M. resources, when many cognitive resources are put into the external cognitive load which is unrelated to the task, there are fewer related cognitive resources that can be invested in the internal cognitive load which is related to the task. Therefore, cognitive load theory holds that the external cognitive load should be reduced as much as possible and the use of related cognitive resources should be improved as well as the internal cognitive load being controlled to an appropriate degree so that individuals can carry out the most effective cognitive processing (Van, 2014; Kalyuga, 2015).
Since the advent of the concept of cognitive load in the 1980s, there has been no unified understanding of its meaning. According to Sweller (1988), cognitive load refers to the level of “mental energy” needed by individuals to process the given information. Cooper (1988), however, asserts that cognitive load refers to all mental activities applied to W.M. at the same time, while Merrinboer (1994), proposes that cognitive load includes multiple dimensions and is the load imposed on an individual’s cognitive system when performing specific tasks. Xuebing, Zhengzheng, & Yue-Jia (2010, 401) define cognitive load by delineating that “in the process of information processing, individuals consciously control cognitive resources and cognitive capacity to make them remain in a highly coordinated and interactive state” while Lin (2005) believed that ‘cognitive load referred to students’ perception and experience of learning tasks, responsibility and time pressure’. So far, due to the multi-dimensional, complex, implicit, and subjective characteristics of cognitive load, researchers have not formed a unified understanding of its definition, especially an operational definition. Different researchers have put forward their own understanding of cognitive load from their own research perspective.
Researchers have classified cognitive load from both static and dynamic perspectives. From the static point of view (horizontal), Sweller (2010) divided cognitive load into three components: intrinsic cognitive load, ineffectual cognitive load, and effective cognitive load. These, in combination, are referred to as the total cognitive load. The internal cognitive load is mainly related to the learner’s prior knowledge and the difficulty of learning materials; the external cognitive load is related to the organization and presentation of learning materials; and the effective cognitive load is related to the depth of cognitive processing (Sweller, 1988). Once an individual performs a task, the remaining cognitive resources used in the processing directly related to learning (such as reorganization, extraction, comparison, and reasoning) will generate the relevant cognitive load. External cognitive load usually brings unnecessary cognitive operation to individuals. However, although related cognitive load also takes up resources in the W.M., it is mainly used for search, schema construction, and automation, which is conducive to an improved learning effect (Lin, 2005).
On the relationship between the components of cognitive load, researchers have long held the view of linear addition (Debue & Van, 2014). Despite the deepening of research, researchers have not yet reached a consensus on the relationship between the components of cognitive load. Whelan (2006) refuted the view mentioned above that the cognitive view is linear. He argued that cognitive load is non-linear and additive. There may be a curvilinear relationship between cognitive load and the number and difficulty of tasks. For example, when learners think that the task is too much or too complex, and the possibility of completion is too small, they may adopt the strategy of giving up, which will lead to a decline in cognitive load. Recently, some scholars have even objected to the tripartite classification of cognitive load. Kalyuga (2011) thought that the concept of related cognitive load might be redundant. Of course, to decide whether this idea is desirable, we need consider not only theoretical thinking but also further empirical research.
Xie and Selvendy (2000) believed that the traditional classification of cognitive load was imprecise because learners’ difficulty and psychological effort in the process of learning or completing tasks were always fluctuating and dynamic. Therefore, they proposed a multi-classification model of cognitive load, which divided cognitive load into instantaneous load, peak load, accumulated load, average load and overall load. In this classification, instantaneous load represents the dynamic component of cognitive load. Peak load is the maximum value of instantaneous load detected when completing a task. Cumulative load is the total load that learners feel when completing a task. Average load is the average intensity of the load that learners feel while completing a certain task, and total load is the total load of the whole cognitive task representing the total amount of load experienced. Xie and Selvendy maintained that their multi-classification model was more accurate and complete for the description of cognitive load. They stressed that each type of cognitive load had its unique significance and cannot be mixed. Generally speaking, the classification of Sweller (2010) reflects the composition of cognitive load at a certain time point or over a certain period, while Xie and Salvendy’s (2000) classification considers the fluctuation of cognitive load, which can be regarded as the classification of cognitive load during a certain period of time.
Sweller et al. (2011) classified individual cognitive load into three categories based on different cognitive load sources: internal cognitive load, external cognitive load, and related cognitive load. In recent years, with the rise of metacognitive concepts and the emergence of related research results, some researchers have proposed a fourth cognitive load, namely metacognitive load. Cognitive loads generated by individuals are not unlimited and unrestrained. All cognitive loads will consume individual cognitive resources and occupy individual W.M. capacity. However, cognitive resources and W.M. capacity are limited, and cognitive load is also based on the two. Therefore, the total amount of these three cognitive loads is limited, and they are in a mutual relationship of restriction.
2.4.1 Internal cognitive load
Internal cognitive load is generally caused by factors such as the complexity of learning materials and the individuals’ prior knowledge and experience. The learners’ existing knowledge and experience are generally stored in LTM in the form of schemata, while learning materials need to be processed in W.M. If there is no connection between learning materials and schemata stored in the brain, or the connection is not close enough, W.M. needs to temporarily construct the relationship between W.M. and schemata stored in the brain. If there are no schemata available in the LTM, there is a lack of competent knowledge related to learning materials. Learners need to temporarily construct new schemata, which makes more demands on them. Due to limited cognitive resources and attention resources, individuals will feel a higher internal cognitive load. On the other hand, if the learners are familiar with the content of the learning materials, they can quickly incorporate them into the existing schemata or establish a corresponding relationship with these schemata; W.M.’s elements will be reduced and the load of W.M. will be lightened.
Internal cognitive load is mainly determined by the nature of learning materials and learners’ levels of knowledge and experience. The nature of learning materials, that is, the difficulty and complexity of learning materials, refers to the number and interactivity of the materials’ elements. The more elements, the higher the interactivity, the more complex and difficult the materials are, and the higher the intrinsic cognitive load brought to learners. But the perception of the difficulty degree of the same learning material will elicit different feelings from different learners, and the internal cognitive load brought to the learners is also different. Compared with learners with a low level of knowledge and experience, learners with a high level of knowledge and experience have lower difficulty in learning materials and lower internal cognitive load. Because the intrinsic cognitive load is mainly determined by the nature of learning materials and the level of knowledge and experience of learners, it is difficult to change under the given conditions. However, some researchers believe that the internal cognitive load can be changed and have explored teaching methods which may be utilized to reduce it.
The content of the learning materials themselves and the learner’s own previous experience are the main factors that determine whether the internal cognitive load is high or low. In short, for the same learner, if the learning material is relatively easy for the learner, that is, the learning material has a ready-made connection with schemata in the brain, then the internal cognitive load will be low. If the learning material is more difficult for the learner, that is, the learning material and the pre-existing schemata in the brain are not connected, and if a new schema needs to be constructed temporarily, the learner’s internal cognitive load will be on the high side. For example, it is easier for TCFL to learn ‘body’ than to learn ‘strengthening body.’ This is due to the different degrees of difficulty in learning materials. For the same material, if the learner has a lot of previous experience of the text contained in the learning material, then the speed of incorporating the text into the known schema will be faster, at the same time, the burden on W.M. will be reduced, and the internal cognitive load will be lower.
On the contrary, if the learner does not have relevant prior experience of the text contained in the learning material, the learner cannot quickly incorporate the text into their known schemata. Simultaneously, the burden of W.M. will be heavier, and the internal cognitive load will be higher. For example, when teaching Chinese as a language, it is easier for students with higher primary levels to learn than it is for those with lower primary level, which is why experts in a certain field find it easier than novices to learn knowledge in this field. However, because the internal cognitive load is only related to teaching materials, teaching content, and learners’ previous knowledge, any external factors cannot change a teaching material’s internal cognitive load. However, teachers should think about keeping students relaxed to accept the knowledge of high internal cognitive load in the process of teaching design. This also reflects the teaching principle of taking learners as the main subject in problem-based learning.
The internal cognitive load is caused by the number of elements in the schema that learners need to organize when they are using WM. The number of elements in the schema is directly proportional to the individual’s internal cognitive load. The greater the number of elements, the higher the internal cognitive load. The level of individual cognition is related to learners’ professional knowledge and the complexity of learning materials (Sweller, 1988). For example, if a learner has stored a lot of experiential knowledge when learning knowledge in a certain field, he will have a lower internal load when learning new knowledge in that field. When the W.M. processes these elements at the same time, it will certainly increase the burden on the W.M., which will lead to a higher internal cognitive load. This is not difficult to understand, in a professional field. Novices learning new content need to spend more time and energy on their learning than experts, and the learning effect (i.e., the result of their learning) is often not as good as that of experts.
Some researchers have refined the concept of internal cognitive load to make it more specific. It is divided into two: externally determined internal cognitive load occurs if the factors that cause cognitive load are complex and diverse. If the internal cognitive load is caused by the previous knowledge and experience of the individual, however, it is called internally determined internal cognitive load (Seufert, 2007). Studies (Tabbers, Martens & Merriënboer, 2011) have shown that when individuals use multimedia tools to learn, hyperlinks do not play a role in the case of high internal cognitive load. On the contrary, they can play a positive role in low cognitive load when individuals have rich previous experience, sufficient knowledge reserves, and use simple learning materials.
2.4.2 External cognitive load
External cognitive load is the demand on W.M. caused by the organization and presentation of learning materials, and it is the cognitive load that hinders learning. In addition, if the organization and presentation of learning materials are not directly related to the schemata construction or automation process in the learner’s brain, this will interfere with the learner’s learning and lead to external cognitive load. For example, when middle school students learn the nature of quadratic functions, if the teacher only talks about the nature of quadratic functions but does not combine this with specific examples and graphics, it is difficult for students to relate the content of the teaching to their own knowledge and experience, which only adds to the external cognitive load of students. However, if the teacher uses the method of combining numbers and figures and then reinforces students’ external recognition by giving examples the external cognitive load is lightened, and quadratic functions can then be understood more deeply. We can optimize the design of teaching processes by changing the presentation of learning materials, controlling and reducing students’ external load, and enhancing students’ understanding.
The external cognitive load is produced by an unreasonable material presentation and teaching design. For example, content and activities unrelated to the learning theme will cause external cognitive load. External cognitive load interferes with and hinders students’ information processing, which is disadvantageous to students’ schemata construction. However, because the teaching design can be changed, the external cognitive load can be controlled. We can reduce the external cognitive load by designing teaching more appropriately. For example, when learning about transmembrane transport of materials, we can increase the external cognitive load if we use pure text. Presenting the concept to students by oral or written explanation will bring higher cognitive load to them, but the external cognitive load on students can be reduced by presenting the concept through a combination of pictures and graphics or with multimedia animation.
External cognitive load is often related to instructional design, mainly from the organization and presentation of learning materials. Because this kind of load is unnecessary and redundant in learning, researchers also call it ineffective cognitive load’ (Paas, Renkl & Sweller, 2004). According to the theory of limited resources mentioned above, in the process of learning, the cognitive resources used by learners in the processing of visual and auditory materials are limited. When using vision to present the text content of the learning, the visual cognitive resources will compete with each other, resulting in an increase in visual cognitive load. For example, when a Chinese learner is learning the word “down jacket”, if the teacher simply uses words to show the word, then this way of text narration and explanation will not only make the learner feel bored but also increase the external cognitive load on the learner; however, if the teacher uses a picture with a down jacket and adds words to explain to learners, then these learners’ external cognitive load will be reduced, which will be more conducive to vocabulary teaching. Therefore, when teachers organize and present relevant learning materials, they should pay attention to whether the organization and presentation methods are scientific, and whether the stimulus presented can help solve the problem. For example, do not use some ambiguous pictures and words in vocabulary teaching, which not only increases the learners’ external cognitive load but also leads to a waste of learning time and energy. Therefore, cognitive load can be adjusted and changed by teachers. In other words, in contrast with the uncontrollability of internal cognitive load, external cognitive load can be reduced by improving teaching design to improve teaching efficiency and learners’ interest in learning (Kalyuga, 2011).
In this learning process, the external cognitive load does not directly affect learning, but it can be caused by the psychological activities stimulated by the external environment. When learning materials that individuals come into contact with are not directly related to their own schemata or related automation, this can lead to individual external cognition load. For example, when the teaching materials (including words and pictures) presented to learners are not closely related to the learning content or learning topic, they will increase the external cognitive load; when individuals use unfamiliar multimedia tools to learn knowledge in certain fields, they will also increase their external cognitive load, because they need to use cognitive resources to learn knowledge in these fields If one is not familiar with multimedia tools, one will lose cognitive resources as compared with when one is familiar with multimedia tools. Suppose the cognitive resources occupied by the individual’s external cognitive load affect the learner’s W.M. capacity. In that case, it will cause the learner’s learning progress to be slow, which can result in low performance or no performance at all. Research shows that in the process of learning, cognitive processing often used by learners does not necessarily help learners to improve their learning effect, and may even hinder their learning. This process will waste a lot of time and energy and affect the learners’ learning progress and efficiency (Pass, 2003).
2.4.3 Related cognitive load
If the learning task is less difficult for learners, the cognitive load is consequently lower. Learners can use the remaining cognitive resources for deeper processing, such as reorganization, extraction, coding, comparison, and reasoning about learning materials. The cognitive load generated by these activities is the related cognitive load, which is conducive to the construction of schemata and promotes learning, so it is an appropriate cognitive load (Paas, Renkl & Sweller, 2004).
Related cognitive load is the element of cognitive load directly caused by instructional design, which helps students construct new knowledge. Related cognitive load is conducive to the construction of schemata and plays an important role in automating schemata. Under the condition of sufficient cognitive resources, the remaining cognitive resources can be used to regulate the learning process and encourage learners to carry out deep-seated schema construction. If the supporting examples corresponding to the concept are properly introduced when explaining the concept, this can help the student’s ability to understand the concept. Because the related cognitive load is caused by instructional design, it can be changed. In teaching, we can increase the related cognitive load to promote students’ understanding of conceptual knowledge (Xie and Salvendy, 2000).
The sum of these three types of cognitive load is termed total cognitive load. However, the cognitive resources in W.M. are limited, and the allocation of resources follows the rule of “this is more than that is less.” Therefore, only when the cognitive resources are sufficient or the internal and external cognitive load are low can more related cognitive loads be added for advanced information processing such as reorganization, comparison, and reasoning. Teaching how to control these three kinds of loads and how to allocate cognitive psychological resources is a problem worthy of discussion (Paas, 2003)
Unlike internal and external cognitive loads, related cognitive loads are not generated by learning materials. According to Sweller (2005), the so-called related cognitive load refers to that which occurs when a certain learning task is finished. The remaining cognitive resources can be used in the cognitive processing directly related to learning, and the cognitive load appearing at this time is the related cognitive load. To put it simply, if a learner’s learning task is less difficult, then the internal cognitive load is low, which leaves the learner with cognitive resources to spare. Therefore, the learner can use these remaining cognitive resources to promote the construction of other lexical schemata. These inputs are not necessary but are conducive to the construction of lexical schemata which is what is referred to as related cognitive load. For example, in vocabulary teaching, when teachers teach the word “watermelon,” they add the words for “Hami melon,” “papaya” and other fruits at the same time. Although these words increase the cognitive load of learners, they help to expand the vocabulary of “melon” fruits, and students’ knowledge, which helps draw inferences from one instance and deepen the understanding of the original vocabulary. This is the general meaning of related cognitive load. Related cognitive load differs from external cognitive load in that related cognitive load is not a load that is disruptive to learning, but rather it is conducive to learning. In a certain sense, related cognitive load can improve learning efficiency, so this load is usually called effective cognitive load.
In addition, related studies show that cognitive load can be additive, which would mean that an individual’s total cognitive load = individual internal cognitive load + individual external cognitive load + individual related cognitive load. Because the total amount of cognitive resources available to a person is limited, the maximum cognitive load of an individual is relatively fixed. Suppose both the internal and external cognitive load of the individual are at a low level; in that case, the level of related cognitive load can be high, which is very beneficial for learners’ learning. If an individual is experiencing a high level of internal and external cognitive load, then the related cognitive load level should be kept lower. The cognitive load level that is not conducive to learning will be high for learners, so it will hinder learning. Therefore, we should try our best to improve learners’ cognitive load and reduce their internal and external cognitive load. However, as mentioned above, internal cognitive load cannot be easily reduced. Therefore, we should principally use some methods to improve individuals’ related cognitive loads and reduce their external cognitive loads, to promote learners’ learning. This requires instructional designers to arrange instructional design in the teaching process: if the internal load of learning materials is low, the external load of instructional design is also low, and learners’ cognitive resources have sufficient surplus, learners’ learning can be promoted through relevant cognitive load. It follows that if the internal load of learning materials is high, teachers should try to reduce the external cognitive load in teaching design. In the later scenario, educators should release the W.M. capacity of learners, and add as little related cognitive load as possible to ensure that learners have sufficient cognitive resources for learning. Therefore, in this process, grasping a rational and scientific approach to teaching design is very important.
Related cognitive load (effective cognitive load), which is exerted through the learners’ learning knowledge, will not use up cognitive resources directly on the learning object, such as integrating learning material elements to build a new schema. In the process of construction, individuals consciously mobilize higher-level cognitive processing (reasoning, abstraction, reorganization, etc.). To master new knowledge, related cognitive load will play a promoting role; at the same time, it will increase the cognitive load accordingly (Sweller, 2005). Many factors affect cognitive load, including individual motivation, emotion, cognition, and metacognition. When the external cognitive load and internal cognitive load are very high, cognitive resources will have been reallocated, resulting in no additional cognitive resources available for direct processing in learning. In other words, a lack of cognitive resources leads to individual related cognitive load. The related cognitive load includes a kind of negative cognitive poetry, which was proposed by Valcke (2002). It means that individuals will have a monitoring process when using new elements to construct storage schemata, and psychological resources will also be used in the monitoring process. Although metacognitive monitoring activities will increase cognitive load, it will improve individuals’ academic performance or task performance, so it positively affects the learning of new knowledge or task completion operation (Seufert, 2007).
2.4.4 Metacognitive load
In addition to the above three cognitive loads proposed by Sweller when he established the cognitive load theory in the 1980s, Valeke formally put forward the concept of metacognitive load in 2002 based on cognitive load theory and metacognitive theory. Generally speaking, the metacognitive load is part of the related cognitive load. It is an effective cognitive load caused by metacognitive activities. It is the load that the W.M. bears when it chooses, organizes, integrates, stores and distributes, monitors, and coordinates information.
The four components of cognitive load interact dynamically, and there is a phenomenon of fluctuation in the process of accomplishing any particular task, but the total amount that the brain can cope with at any one time remains unchanged. The total amount of human cognitive resources is fixed. If the internal load is large, the resources available for related cognitive load reduce accordingly. Then, if the external load increases, the learning effect will be affected. If the internal load is small, the external load is not very important because there are sufficient cognitive resources available to provide the related and metacognitive loads. Therefore, in learning and teaching activities, we should pay attention to the rational optimization of cognitive loads.
2.5 The effect of cognitive load in teaching
In recent years, under the guidance of cognitive load theory, researchers have made a series of studies on instructional design and found many possible effects on learning, including goal-free effect, sample effect, attention distraction effect, channel effect, redundancy effect, familiarity reversal effect and so on.
2.5.1 Goal-free effect
In middle school geometry, a typical problem is to calculate the size of a particular angle in a complex geometric figure, a problem with a specific goal. If students are asked to find as many viewpoints as possible in the geometric figure, it will become a problem with a free goal, which is helpful for learners to learn and transfer. The name for this is the goal-free effect (Paas & Kirschner, 2012).
2.5.2 Sample effect
Sweller et al. (1997) pointed out that when dealing with complex cognitive tasks, providing well-designed and effective examples to learners can effectively improve their problem-solving level, which is the sample effect. Samples can present the procedures needed to solve problems, highlight the characteristics of related schemata needed to solve problems, make students pay attention to schemata-related information, reduce the number of attempts in which mistakes are made, and reduce the load on W.M., thus promoting schema acquisition and rule automation.
2.5.3 Attention dispersion effect
Samples can promote learning, but when learners have more experience in many fields and more prior knowledge and then go back to extract the sample information, samples will distract the learners’ attention, thus interfering with learning, resulting in the separation of attention effects (split-attention effect). The research of Sweller (2002) showed that the separation of sample and text content information in space or time would distract learners’ attention, increase cognitive load, and interfere with learners’ learning. Sweller (2002) also found that reading traditional psychological experimental reports is made more difficult because the conclusion and discussion are separated. However, the reader must consider the relationship between the two parts at the same time in order to understand the meaning of the results; there is therefore a distraction effect. If we can integrate the results with the discussion, we can eliminate the distraction effect.
2.5.4 Channel effect
Baddeley (1992) pointed out that WM has two channels for information processing: the visual processing channel and the auditory processing channel. The two channels are relatively independent, focusing on visual and auditory information, respectively. Therefore, the use of a single form of information presentation cannot make full use of the WM system. In contrast, the comprehensive use of diverse forms of information presentation can help to improve the use of WM, resulting in a channel effect.
2.5.5 Redundancy effect
Although examples can produce sample effects, they are not always beneficial to learning. At the later stage of learning, the previous examples become redundant information with the accumulation of learners’ knowledge and experience. If examples continue to exist, they will occupy learners limited cognitive resources and attention, interfere with learning, and produce a redundancy effect. Rentl and Atkinson (2003) found that examples are redundant for skilled learners because learners have to allocate certain cognitive resources to process these examples and guidance, but they occupy cognitive resources, resulting in a higher cognitive load, which will interfere with learning.
2.5.6 Expertise reversal effect
With the further deepening of learning, the novice’s experience is constantly accumulating, moving in the direction of the level of experts. In this way, the original teaching method’s effectiveness may be reversed, from a previous positive advantage role to a negative interference role. This phenomenon is known as the expertise reversal effect. Kalyuga et al. (2003) found that the explanatory and guiding functions of examples only promote beginners. In contrast, for skilled and experienced learners, this effect will be reversed, not playing a positive role, but reducing the learning effect.
The effect of goal freedom refers to the substitution of goal-free topics for traditional problems that provide learners with specific goals; the example effect refers to the replacement of traditional problems with solved examples, which must be studied carefully. The completion effect refers to the replacement of traditional problems with unfinished problems, providing partial solutions in the problems, and the rest being completed by learners. The decentralization attention effect refers to the use of an integrated information source to replace multiple information sources, often pictures and accompanied by text. The formal effect refers to the use of oral interpretation text and various forms of visual information sources instead of written text and charts and other single forms of visual information sources. The imagination effect refers to making learners imagine or use psychological practice materials to replace additional traditional learning. The independent interactive element effect refers to the presentation of independent elements to learners before presenting complete materials. Element interaction refers to the disappearance of teaching effects such as the imagination effect when using materials with low element interaction, while they reappear when high element interaction is used. The variant effect refers to a way of increasing variability and task presentation in different variable situations.
Teaching methods which are effective for new learners are ineffective or even have a detrimental effect when learners have acquired more professional knowledge; the guidance retirement effect is that with the development of a knowledge-based central executive, the central executive based on teaching gradually retreats, and complete examples can be replaced by partially completed examples. With the further accumulation of professional knowledge, partially completed examples can be replaced by problems; the redundancy effect refers to using one information source to replace multiple self-consistent information sources.
2.6 Development status of cognitive load
At present, although there is no unified view internationally on the definition and classification of cognitive load and the relationship between cognitive structures since cognitive load theory was first proposed, it has been widely studied by scholars globally. Research on cognitive load is developing in quality and quantity. According to the statistical data of China National Knowledge Infrastructure (CNKI), with “cognitive load” as the theme and searching time nodes for core journals from 1998 to 2018, a total of 397 related academic papers were obtained, and the research trend of cognitive load was determined after organizing the pertinent literature. The number of papers published on cognitive load has been increasing year by year in recent years. The concept of cognitive load has been used in education, psychology, linguistics, computer science, library and information, transportation, and other disciplines.
In terms of research content, Chinese scholars pay particular attention to applying cognitive load theory to practice. Researchers have used cognitive load theory to provide students with more efficient learning and teaching approaches (such as flipped classroom, video micro classes, motor skills, etc.) (Alasraj, Freeman & Chandler, 2013).In the aspect of artificial intelligence, some researchers focus on the relationship between cognitive load, task characteristics, and individual characteristics. They also explore the comprehensive evaluation method of cognitive load in human-computer interaction and the construction of the prediction model of cognitive load change (Meissner & Bogner, 2012). In information retrieval, cognitive load theory has been used to study user information behaviour, optimize cognitive strategies and create a better digital platform for the learning experience. Researchers have also applied cognitive load measurement to the study of diverse fields such as criminal psychology, intelligent electrical appliances, driver driving behaviour, etc. (Alasraj, Freeman & Chandler, 2013). Internationally, researchers have explored the definition and classification of cognitive load, the relationship between cognitive structures, the measurement and structural models of cognitive load, factors related to cognitive load, and the application of cognitive load in psychology, education, lie detection and other fields (Alasraj, Freeman & Chandler, 2013).
There are two ways to process information in WM: conscious processing and automatic processing. Conscious processing consumes a large amount of WM resources, while automatic processing of information does not require conscious monitoring and requires fewer WM resources. No matter which processing method is used, schemata can be easily searched and extracted by WM as information blocks or rich information units. If a schema is used repeatedly, the result is automation. Automatic schemata are more conducive to WM extraction, and WM can use more resources to process a larger quantity of information. In a sense, automatic schemata do not need WM extraction, and directly drive behaviour; that is, although the capacity of WM is fundamentally different between experts and novices, it is clear that in experts, cognition is schema driven, while novices’ cognition is based on the number of units of knowledge and skills. Therefore, only by constructing schemata and automating them can novices develop into experts.
Cognitive load refers to the total load of the WM system in the process of processing and maintaining information for a specific cognitive task. The basic principle is to reduce the external and internal load and increase the effective load. In teaching, external cognitive load (hereinafter referred to as external load) refers to the load imposed on WM due to improper instructional design, which is not directly related to cognitive processing (schema construction or automation). Ineffective load mainly comes from the improper design of cognitive tasks and activities unrelated to actual teaching Activities that do not help substantive cognition lead to unnecessary cognitive operation of WM, which requires WM to bear a certain load. Therefore, external load is also called ineffective load.
Intrinsic cognitive load (hereinafter referred to as internal load) refers to the load produced by WM in cognitive processing of the amount and interaction of information elements (such as concepts and rules) contained in cognitive tasks. The internal load level depends on the number and interaction of the elements in the learning task itself. Therefore, reducing the internal load means reducing learning, the number of elements in the task itself, and their interactivity.
Effective cognitive load (hereinafter referred to as effective load) refers to the load that WM has when undertaking substantive cognitive operations on cognitive tasks. Substantive cognitive operation refers to those activities that are utilized in schema construction and schema automation, or activities closely related to schema construction and schema automation. Obviously, the effective load mainly comes from the learners’ effective cognition of cognitive tasks. For example, the self-explanation of learning materials may generate an effective load.
Pass and Van Merrienboer proposed two elements (assessment and causality) to further elucidate cognitive load: “These two elements not only control the degree of cognitive load but also constitute a two-dimensional structural model of cognitive load” (Wu Lei, 2016, 56). Sweller (2011, 257-285) put forward three kinds of influencing factors from the perspective of students: “students’ own experience and knowledge, learning materials and ways of organization and presentation.” Paas and Van Merrinboer (2006) put forward three main factors that affect cognitive load: 1) learning tasks: type of learning tasks, motivation, and expectation, motivation method; 2) learning materials: content, way of arranging materials, organization and presentation of textbooks, way of arranging information; 3) learner characteristics: students’ cognitive style, cognitive method, cognitive ability (Shi Hongtao, 2015). Zhao Junfeng (2011), basing his analysis on previous studies, summed up six influential elements: learning organization, students’ characteristics, material difficulty, time, evaluation, and the form of teaching design.
According to the research results of cognitive load theory, I can summarize the influencing factors of cognitive load from the perspective of teaching according to the interaction among learners and tasks (environment) as follows (cf. Jeroen, 2005):
- Task (environment) factors refer to the characteristics formed by the features, composition, and environment of learning tasks. These include the quantity, complexity, time, and novelty of the learning content.
- Student factors refer to the factors that are stable and difficult to change by students themselves. They are often related to students’ own performance levels, mainly referring to their existing knowledge and experience, cognitive ability (memory, thinking, imagination, attention, and perception), and so on.
The factors that influence each other are those ones between students and their tasks (environment). These include the presentation form of the content (the quantity, layout, speed of content presentation), students’ motivation, learning interest, metacognitive ability, emotional arousal level, reward and punishment, and learning evaluation.
For students, the larger the number of learning tasks, the higher the complexity and the degree of novelty of the learning content, and the higher their internal cognitive load in the process of learning, which will make learning difficult, the more measures need to be taken to adjust. The greater the cognitive ability of students, the higher their level of performance, and the more knowledge and experience they have, the lower the internal cognitive load the tasks generate. The more unreasonable the presentation of learning content and the more limited the time, the higher the external cognitive load will be, and the more adverse the impact on learning will be. Appropriate emotional arousal level, positive learning motivation, strong metacognitive ability, higher learning interest, and appropriate punishment and reward will increase students’ input to the related cognitive load and effectively promote learning.
The theory of limited resources holds that human beings have very limited cognitive resources. Students will spend a lot of cognitive resources when learning or solving problems, which brings about a cognitive load (Pan Yinsong & Zheng Cuihua, 2011). When the total amount of psychological resources needed to perform multiple tasks is lower than the total amount people have, people can do different tasks at the same time; but if the total amount of psychological resources needed to perform these tasks exceeds the upper limit people have, there will be insufficient allocation of resources, and cognitive overload will occur, which will hinder people in their learning.
The application of schema theory can transform knowledge into schemata and conserve the associated knowledge in people’s LTM. When a person learns new knowledge, the knowledge in the memory base are categorized quickly and accurately according to the specific situation. In this process, people can reduce their cognitive load without consuming additional cognitive resources (Pan & Zheng, 2011). Schemata can combine a lot of information, and then turn it into a single unit (a schema) to reduce the load of processing with short-term memory (STM). This model explains how one can get rid of the shackles of STM and effectively store information in permanent memory. Schema construction limits the number of elements of WM processing but there is no obvious limit to the amount of information processed. Therefore, schema construction can reduce the load on WM. After schema construction, WM can be further automated through a lot of practice. The automation of rules can make people use as few WM resources as possible to process information, and also maximize the space for learning unfamiliar tasks. This not only decreases the external cognitive load, but also reduces the load on STM, thus improving students’ learning efficiency. Schemata in LTM belong to a knowledge framework, which has a central executive function when learning new materials. When learning new materials, if such knowledge frameworks can be acquired from LTM, materials can be learned through the methods provided by the knowledge frameworks. In addition to the schemata in LTM, other acquired knowledge can also act as a central executor in human learning.
The theory of limited resources indicates that people’s cognitive resources are not unlimited. Schema theory shows that the acquisition of schemata and the automation of rules can compensate for the deficiencies of WM in order to improve students’ learning efficiency (Pan & Fei, 2011). In fact, the theory of limited resources explains why students manifest external and internal cognitive load in the process of learning. A schema is a process of decreasing related cognitive load. Cognitive load theory is related to schemata theory and theory of limited resources. It studies how to adjust and control the load of WM in teaching and how to allocate limited resources, so as to improve teaching efficiency. In the process of teaching, teachers should make clear to students that their cognitive resources are limited. Teachers should take this as an important consideration in choosing and presenting content, designing links and so on. At the same time, it is necessary to help students to acquire and automate the schemata of the learning content in the process of learning, so as to improve the efficiency of their learning.
2.9 Development of cognitive load theory (CLT)
Since John Sweller, an Australian scientist, first proposed the CLT in 1988, other scholars have expanded and developed the theory. The human cognitive structure is the basis of cognitive load theory. In Sweller’s initial theory, the limitation of WM was regarded as the theory space, which was divided into visual memory space and auditory memory space. Then the dual sensory channel effect was proposed based on this. Ericsson and Kintsch put forward another important element of cognitive load theory in 1995: long-term memory. Before 2004, CLT compared human cognition with the natural evolution of animals and proposed some structured teaching effects, including the goal-free effect, sample effect, distraction effect, etc. In 2004, John Sweller scientifically explained the effects of sending messages from cognitive and evolutionary perspectives. The greatest characteristic of CLT is that a series of practical teaching effects and principles can be obtained from it, which can directly guide teachers in the practice of teaching design, and these effects and principles will continue to be scientifically explored and diversified with the deepening of the theory.
Most of the studies on cognitive load are in the fields of psychology, teaching, and medicine. There are both theoretical studies and empirical studies. In recent years, scholars have continued to study the evolution and development of human cognitive structure, constantly strengthening and improving the theoretical basis of cognitive load theory; in teaching, they have carried out theoretical and empirical research on learning tasks based on real tasks, looking for teaching strategies to reduce excessive internal and external cognitive loads.
The study of cognitive load theory began in the 1990s. As early as 1997, scholars had investigated and studied the application of cognitive load theory in teaching. Since 2011, the literature on cognitive load theory has increased year by year, and the field has become more and more extensive. From the initial psychological field to teaching practice, the application of psychological theory has not only helped in the integration and expansion of the academic field but also promoted research in the field of practical application. Based on research on the measurement of cognitive load, scholars (e.g., Paas, 1994) have compared several common scales for measuring cognitive load in various countries and discussed the advantages and disadvantages of these scales. With the growing extent of English teaching, a lot of research has been done on writing, reading, translation, and listening in junior high school and college English. After summarizing the literature, I found that there are few studies on the importance of cognitive load in this area.
Mayer, a well-known contemporary American educational psychologist, and pioneer of cognitive psychology in international multimedia learning, has put forward the cognitive theory model of multimedia learning, which has had a wide influence. In this theory, Mayer (1999, 24) defines the multimedia he is discussing as “the co-presentation of words (Word) and pictures (Picture)”. Words refer to the presentation of material in verbal forms, such as printed text or speech; pictures refer to the presentation of material in pictorial form. Mayer pays great attention to the limitation of learners’ WM capacity in multimedia design. He emphasizes that multimedia design should enable learners’ cognitive activities to be used for learning-related content. In his book Multimedia Learning, Mayer (1999) also pointed out that consideration of learners’ cognitive load in multimedia design will be increasingly important in the future.
With the continuous application of research results on cognitive load, the design thinking associated with considering learners’ cognitive load in educational technology research has also begun to receive extensive attention. In the third edition of Educational Technology Research and Development (Elvis, 2005, 112-168), the application of cognitive load in e-learning is exclusively discussed. The theory of cognitive load is taken as a special topic. This publication reviews the application of cognitive load theory in the teaching field over the preceding ten years, considering the development of cognitive load theory from a broader perspective (see also Richard, Denis & Vasiliki, 2019). The research perspective has gradually expanded from the initial aim of reducing the external cognitive load to paying attention to internal cognitive load and related cognitive load factors. Research methods have shifted from laboratory research to real classrooms.
The Department of Information Management in Taiwan National Central University has studied the application of cognitive load theory in multimedia design from the perspective of reducing external cognitive load. They use lively and diversified presentation methods in multimedia products in order to improve learners’ learning effectiveness and use cognitive load theory to study these issues. Their research includes exploring the effects of cognitive load on learning results, using a range of media for students with different learning styles, and the effects of cognitive load on multimedia computer-assisted learning outcomes.
Some scholars pay attention to the development of cognitive load theory. The research aspects are as follows: from the perspective of cognitive load theory, the relevance to teaching design is discussed, the specific teaching principles proposed by cognitive load theory are applied to subject teaching, and they are combined with specific subject teaching design; there are also theoretical enrichments to control cognitive load effectively (Lin & Yu, 2017).
2.9.1 Application of cognitive load theory in teaching design
Shehu Aliyu Rimintsiwa (2015) proposed combining problem-solving with sample solutions to deal with complex tasks based on cognitive load theory. Tindall-Ford et al. (2015) found that the effect of students’ self-management and separation of attention sample strategy on solving geometric problems was better than that of using separation of attention sample alone. Another advantage of the strategy of separating attention from self-management is to enable students to improve their enthusiasm for participation (Orvis et al., 2009). Learners at different competence levels should have different learning effects (Blayney et al., 2015). The study of Blayney et al. (2015) points out that cognitive load is influenced by the competence level of the learners. Therefore, in my research I will only choose students with similar competence levels in the first year of senior high school as the object of the study. Paas et al. (2003) proposed to improve teaching by using the graph effect, redundancy effect, sample effect, specific goal effect, channel effect, and attention dispersion effect. Cognitive overload in learning can be optimized by the use of WM memory capacity and avoiding cognitive overload in the teaching system. A theoretical framework for the development of Moodle (a teaching management system) has been provided, based on cognitive load theory and self-determination theory (Tiago et al., 2016). Andrade et al. (2015) explored the cognitive load of college students and how to use cognitive load theory to design teaching content. According to Klayuga (2011), instructional design starts with external and internal cognitive loads, and classified related cognitive loads into internal cognitive loads. The insufficiency of these pieces of research is as follows: the internal cognitive load will not be affected by instructional design, while the related cognitive load is affected by the designer of the teaching (the teacher); the two cannot be confused. In short, the study of cognitive load theory in design teaching has significance for this thesis.
Based on the theory of cognitive load, Wang Ming and Cao Daoping (2013) used a literature review to explore all aspects that should be paid attention to when designing useful teaching; they therefore dealt with the cognitive load in the process of teaching and provided effective strategies for the design of teaching. Teaching design can be adjusted by the reversal effect in view of the large amount of information and long duration of complex learning tasks (Zhao & Wu, 2010). According to Pang Weiguo (2011), there are 12 methods to reduce the external and internal cognitive load. Cognitive load theory can be used to design teaching effectively from three aspects: individual differences, learners’ learning materials, and ways of presenting teaching content (Wu & Wesley, 2009). Based on the information processing model and through empirical research, cognitive load theory adjusts teaching design by reducing internal and external cognitive load, but there is still no research on related cognitive load. The following three points should be considered when presenting information: the form of information organization, students’ knowledge level, and the complexity of the selected materials (Lai & Zeng, 2005). The application of cognitive load theory in teaching design can be used for reference in teaching.
2.9.2 Application of cognitive load theory in multimedia teaching
Knigschulte and Anke (2015) investigated the integration of non-voice audio (such as sound effects) into multimedia-based teaching, and combined Moreno’s multimedia cognitive-affective theory, Mayer’s multimedia cognitive theory and Sweller’s cognitive load theory. Richard E. Mayer (2003) explored the relationship between cognitive theory and cognitive load in multimedia learning. By describing the situation of cognitive overload in multimedia learning, he put forward methods and suggestions to reduce cognitive load. Mayer (2005) put forward the theory of multimedia cognition, and carried out a number of psychological experiments, and proved that it is a scientific theory. The results of these studies can be used as reference to lighten the cognitive load caused by multimedia in teaching.
Based on the theory of cognitive load, Wang Bing (2017) provides some principles on how to choose microvideo to reduce three types of cognitive load. In discussing the cognitive load in English multimedia, Liu Weijing (2015) makes a thorough analysis of four common cognitive overload phenomena, and provides four ways to reduce cognitive load in multimedia design on the basis of practice. Tang Xin (2013) put forward the principles of designing and choosing teaching media by analyzing seven strategies summarized by Richard E. Mayer to reduce cognitive load in multimedia with the method of literature research. Tang Xin (2014) provided a methodological reference for teachers in designing courseware. Wang Yuanyuan and Shiqin (2012) explored the application of this theory in setting up a human-machine interface and multimedia teaching, and analysed some factors that cause cognitive load. Cheng Zhi and Zhou Tie (2008) used qualitative analysis to prove the significance of the distraction effect, dual sensory effect, independent interaction element effect and redundancy effect in multimedia instructional design. Chen Liang and Guo Zhaoming (2005) compiled Meyer’s ‘Nine Ways to Reduce Cognitive Load in Multimedia Learning’. By describing the situation of cognitive overload in detail, they put forward suggestions to reduce cognitive load based on Meyer’s three theoretical assumptions. Due to the popularity of computers and improvements in teachers’ level of teaching, multimedia have already been used in the teaching of various disciplines. Therefore, it is of practical significance to study the application of cognitive load theory in multimedia teachings, especially for the teaching of scientific concepts.
2.9.3 Measurement of cognitive load theory in teaching
Cognitive load is not only an important independent variable to predict the effectiveness of instructional design, but also an intervention variable to be controlled in instructional design or a dependent variable in learning process. Therefore, the measurement and study of cognitive load has become an important research topic. The cognitive load structure is composed of two dimensions: the causal factor and the evaluation factor (Paas, 1994). The evaluation dimension reflects the measurement dimensions of cognitive load, including mental load, mental effort, performance and the interaction between them. Based on the above model, many researchers have proposed methods to measure cognitive load. Two dimensions, objectivity (subjective or objective) and causality (direct or indirect), have been devised to get different methods to measure cognitive load.
Tamara et al. (2010) summarized recent research on sample solutions, animation production and cognitive load measurement. The advantage of this research is that it deepens the depth of the theoretical research and expands the scope of its research. Roland et al. (2003) explored the process of directly measuring cognitive load in multimedia learning. Their study asserted that no single measurement is the best, so the most appropriate measures need to be explored continuously. Subjective rating evaluation has higher reliability and is more suitable for the study of teaching. At the same time, it provides a reference tool for their study.
Sun Chongyong and Liu Dianzhi (2013) used a two-task experiment to compare the validity and sensitivity of three cognitive load subjective assessment scales. The results show that the response of the sub-task is good, and it has strong stability and anti-disturbance. As a subjective evaluation of cognitive load, all scales have good sensitivity, and their validity is good. After synthesizing the indicators, it was found that the sub-task scale is a near ideal tool for measuring cognitive load when the task difficulty is medium or low. Cai Yanling (2009) expanded the research on measuring cognitive load in multimedia teaching, mathematics, statistics, and language learning, and put forward seven evaluation criteria for evaluating the validity of measurement methods. He then evaluated psychological index measurement, subjective measurement, and behavioural measurement. Cai Yanling (2009) carried out two important measurement techniques in subjective measurement. Compared with these other measurement techniques, subjective measurement is more sensitive than the subjective workload assessment technique (SWAT) in reflecting the cognitive load difference between task complexity and other factors. The reliability of NASA-TLX (Task load Index) measurement results has a higher correlation with the performance of learners. The advantage of the research of Cai Yanling (2009) lies in providing an effective tool for measuring cognitive load in reading teaching.
Due to the implicit complexity of cognitive load, the measurement of cognitive load needs to be carried out from multiple perspectives. Through the efforts of psychologists, different methods of measuring cognitive load are proposed, among which commonly used methods are subjective measurement, biological measurement, and task performance measurement.
Because of the difficulty of learning tasks and the degree of individual effort of learners, cognitive load affects the occupation of psychological resources. On this basis, subjective measurement reflects the cognitive load by the feelings of learners in the learning process. The specific approach is that learners reflect on their own learning process, and reflect their psychological efforts, learning material difficulty, and time pressure in the learning process through questionnaires. The subjective measurement method is easy to operate, does not need special instruments and equipment, and is easy to use and master. At the same time, because it is measured after the learners finish the learning process, it will not affect the learning process and is easily accepted by learners. In addition, because subjective measurement is the accurate expression of learners’ learning feelings, it has high reliability. However, subjective measurement also has defects. It is difficult to compare the cognitive load produced in different types of learning tasks by subjective measurement. Among the evaluation scales used in subjective measurement, Paas’ Self-evaluation Scale is the most used scale. It uses a nine-level scoring standard to evaluate the learners’ psychological efforts and the difficulty of learning tasks, so as to reflect the cognitive load in the learning process. The specific method is as follows: the subjects reflect on their own learning process. According to their feelings in the learning process, the degree of psychological effort and material difficulty increases from 1 to 9. Participants choose the number that expresses their feelings most accurately.
Physiological measurement is a method to evaluate the cognitive load of learners by measuring the physiological reactions such as heart changes, brain activities, and eye activities in the learning process with the help of corresponding instruments and equipment. It is an indirect measurement method, and the data obtained are relatively objective and accurate. The physiological measurement method can continuously measure the physiological activities in the learning process and show detailed changes in cognitive load, which is less possible with other measurement methods. However, physiological measurement is not infallible. For example, the changes in physiological activities measured may be caused by factors unrelated to cognitive load, such as environment and emotion. In addition, physiological measurement needs expensive instruments and equipment, and the method and the analysis of data are not easy to master, which makes it difficult to measure cognitive load with physiological measurement methods.
Physiological measurement is used to indirectly evaluate cognitive load by measuring the physiological reactions of learners in the process of learning or task completion. The theoretical premise of physiological measurement is that any change of psychological function is reflected by a series of physiological indicators; so, it is assumed that the change of cognitive load will also cause changes in some physiological indicators, that is, the cognitive load can be indicated by heart activity (such as heart rate), brain activity (such as evoked potential), eye activity (such as pupil diameter, blink rate), etc. In contrast with other methods, the physiological measurement method can better result in detailed trends over time with which it creates a model of cognitive load, such as instantaneous load, peak load, average load, cumulative load, and so on.
Task performance measurement is an objective measurement method. It evaluates learners’ cognitive load by measuring their performance on a task, whether by single task measurement or dual task measurement.
(1) Single task measurement
Single task measurement is a method of measuring learners’ cognitive load according to the results of completing a single task. This method considers that with the increase of cognitive load, the occupied cognitive psychological resources will also increase, and the task performance of learners will be impaired, for instance, with an increased error rate and a decrease in efficiency. Task accuracy and error rate, reaction time and completion time are indicators of single task measurement. Due to the complexity of the internal mechanism and the change of physiological resources involved in the task, it is difficult to fully express the cognitive load brought about by one or two indicators of a single task.
(2) Dual task measurement
Dual task measurement is the term used to describe the measurement of the cognitive load of learners who complete two tasks at the same time in a given time. The two tasks can be classified as the primary task and the secondary task. The primary task is the task that learners spend more energy to complete, and the secondary task is the task that learners use their surplus energy to complete. These two tasks need the same resource channel. To complete the two tasks at the same time, resources should be allocated between the two tasks, so that the cognitive load can be judged according to their performance. However, the dual task measurement method is also limited. When completing the primary and the secondary tasks, the two may interact with each other, which will affect the measurement results.
In order to measure the actual cognitive load, it is very difficult to use only one measurement method. In the actual application process, different measurement methods can be selected for different measurement objects. Multiple methods can be combined so that different measurement results can support each other and improve measurement triangulation accuracy.
With the development and maturing of cognitive load theory, its application field is becoming more extensive. In the field of teaching, cognitive load also plays a significant role in guiding effective teaching. With reference to instructional design, Sweller (2002), the founder of cognitive load theory, has summarized the basic principles of instructional design, the product of extensive research.
(1) Free goal effect
Free goal effect refers to the fact that when there are multiple learning objectives or the learning objectives are not clear at the same time, learners are allowed to determine their own learning objectives, which has a positive role in promoting their learning and ability to transfer their learning to other situations. According to cognitive load theory, if students are asked to think about a specific problem with definite goals, they will process multiple conditional information on WM at the same time in the process of thinking, which will lead to an increase in WM load. The use of the free goal effect can avoid unnecessary cognitive load caused by specific problems and reduce the external cognitive load experienced by students. It constructs schemata and cultivates students’ divergent thinking.
The example learning effect refers to the fact that providing correct examples to beginners can reduce the external cognitive load and help them understand new knowledge. It is generally believed that exemplars can present the essential attributes of conceptual knowledge and clearly show the relevant information of schema characteristics so that students can reduce trial errors in the learning process, focus their attention on useful information, and reduce the load on WM, which is conducive to the construction and automation of schemata. For example, after learning a new concept, teachers should provide students with a correct case for discrimination, so as to consolidate the new learning concept and encourage students to form the correct schema in the brain. If an incorrect case is provided for students to judge, it will increase the external cognitive load of students and consequently interfere with the construction of new concepts.
The problem completion effect can be used to replace traditional exercises by providing the students with questions in which the solution steps have only partially been completed, and where learners must complete the remaining steps. To provide students with some of the problem-solving steps is actually to point out the direction and method of solving problems, reduce the cognitive load, and make students focus more effectively on solving problems.
The sensory channel effect refers to the concept that information is presented in the form of visual information and auditory information. The processing of these two kinds of information by WM is separated. If the information is presented only in the form of vision or hearing, a part of WM will be idle, and cognitive resources, therefore, cannot be well utilized. However, using multiple forms to present information can make better use of cognitive resources; therefore, the information processing efficiency of WM is improved.
When there is both text information and picture information in learning materials, if they are presented separately, learners will pay attention to multiple information sources which will increase the burden of WM and is not conducive to the effective learning. It is called the separation of attention effect, which means that the two should be appropriately integrated.
2.10 Research status of cognitive load
The initial model of the cognitive load was constructed from two dimensions of causal factors and evaluation factors, which pushed the research of cognitive load to a new height (Paas, 1994). After more than ten years of research, Paas and colleagues proposed an improvement to the model in 2017 which represents an adjustment to the model of cognitive load structure from the first model. The theoretical research has laid a foundation for the maturity and more effective guidance of cognitive load theory. The research on cognitive load measurement can be divided into four areas: indirect subjective measurement, indirect objective measurement, direct subjective measurement and direct objective measurement. The scales designed based on the above four measurement directions have also achieved fruitful practical research results.
With the deepening of the research, CLT is gradually being applied to determine how to effectively promote problem-solving and improve learning effect. By now, the theory has become one of the most influential theoretical frameworks in the field of learning and teaching. Chinese scholars have widely studied the rise of cognitive load theory. From the perspective of the types of articles, most of them are translations of or introductions to international research development. For example, ‘A review of cognitive load theory ‘(Zhang Hui, Zhang Fan, 1999), ‘Cognitive load theory and its development’ (Chen qiaofen, 2007), ‘Cognitive load theory and its research progress and thinking’ (Tang Jianlan, Zhou yingsuo, 2008) are all by Chinese researchers and are mainly introduced from the basic concept and research progress of cognitive load theory rather than providing original research or insight. In terms of measurement, the main literature includes ‘Introduction to the measurement model of cognitive load’ (Zhang, 1997) and ‘Measurement of cognitive load and its application in multimedia learning’ (Sun, 2015), which introduce measurement mechanisms and methods relating to learners’ cognitive load.
At the practical level, most of the research on cognitive load theory focuses on its relevance for and guiding influence on instructional design. I searched CNKI with the key words “cognitive load” and “physics”, and found that the subjects involved included multimedia, chemistry, Chinese, mathematics, English, biology, physics and so on. Based on the statistics of the number of papers published in the field of teaching from 2000 to 2019, it seems that the volume of research on cognitive load theory in the field of teaching is increasing year by year, reaching a peak in 2016 and declining slightly in 2018 and 2019. Through literature review, I found that in the past years, scholars from all walks of life combine cognitive load theory with teaching in terms of translation and theoretical research, but there are still a large number of practical research publications. It can be seen that research in the field of teaching needs to further combine cognitive load theory with the characteristics of teaching content, expand its guiding role in front-line teaching practice and open up new discipline theory related to cognitive load theory.
The concept of “limited energy” has also appeared in previous studies. For example, according to Broadbent (1958), a British psychologist, people are faced with a large amount of information, but in the same time interval, the ability of an individual’s cognitive system to process information is very limited, so it is necessary to adjust through filters to make the burden on the central nervous system affordable and to increase the limited energy. He believed that the cognitive load processing ability is higher when faced with two languages with different syntactic structures. Dawrant (1996) speculated that the interpreter would adopt the strategy of “storage and processing capacity” in the process of interpretation. Taking Chinese to English translation as an example, he believed that translators would adopt the “prediction” mode of attention allocation due to their different syntactic structures, thus effectively reducing the workload of WM. Roderick Jones (2018) pointed out that in the process of interpretation, the interpreter does many tasks at a time. The interpreter should listen to, understand, record and read the documents used in the meeting, analyse and speak. The above tasks require interpreters to achieve the transformation from language A to language B, even language C. Every job is fleeting, so it is hard to go back and analyse the work of an interpreter. This argument also supports the cognitive load model theory, which shows that interpretation tasks are complex and involved, and each task needs reasonable energy allocation.
Sijia Chen (2018, 467-468) explored the process of note taking and consecutive interpretation from the perspective of cognitive load. This study mainly explored the relationship between the choice of notes, cognitive load and interpretation performance in professional interpreters with seven years of professional experience through pen recording, eye tracking and voice recording. After that, the study provides a theoretical and methodological considerations on cognitive load measurement of interpretation, and draws the conclusion that translation choice not only leads to differences in time needed for the conclusion of the tasks but also in cognitive needs. Moreover, the relationship among notes, cognitive load, and interpretation performance will also be affected by language directivity. For example, English to Chinese and Chinese to English translations will differently affect the choice of interpretation notes, and therefore also affect the interpreter’s cognitive load.
Merrinboer and Mayer (2003) proposed that the number of learning tasks and the degree of interaction between units of knowledge are the determinants of the level of internal cognitive load. Part tasks and whole tasks are two aspects to consider when aiming to reduce the internal cognitive load. Mayer (2000) conducted a study on the differences among different students and found that auditory stimulation, especially music, can effectively promote the learning efficiency of individuals with a higher pre-knowledge level. When students have higher pre-knowledge and the internal cognitive load generated by teaching content is low, students are in a relatively relaxed learning state; further, the encouraging effect of music has an inhibitory effect on the negative unrelated effect of external cognitive load. For the students with lower pre-knowledge level, the knowledge complexity is directly proportional to the external cognitive load (Paas, 2004). For students with higher level of pre-knowledge, the accumulation of pre-knowledge can effectively transform into complex knowledge. Therefore, such students have low demand for the reduction of external cognitive load. The level of expertise possessed by students can affect cognitive load (Rikers, 2004).
In terms of the integration of cognitive load in different teaching theories, Sweller (1998) continuously developed the application of cognitive load theory through long-term research, based on the basic elements of the theory and expanding constantly combined with other teaching research theories, such as evolutionary biology, cognitive brain science, mirror nervous system and so on. Taking biology as an example, according to the process and composition of human evolution, Sweller derived the formation process of human cognitive structure, and proposed that the cognitive process also presents the state of development and adaptation with the continuous change of environment. In the later stage of his work, Sweller extended the cognitive principle into five aspects: information storage principle; adoption, and reorganization principle; change restriction principle; random occurrence principle; environmental organization, and link. In order to show that the multimedia animation learning method is more intuitive and effective, van Gog (2009) combined the thinking behind the mirror nervous system and cognitive load theory, which had a good effect on biology and other disciplines. Cognitive brain science, combined with cognitive load theory, can work together in the learning of complex knowledge (Kirschner, 2009).
Wang Ming and Cao Daoping (2013) proposed that teaching design at the present time must emphasize the influence of cognitive load and deal with the relationship between the individual and his/her cognitive load. Zhao Liying and Wu Qinglin (2010) proposed to integrate the reversal effect into the teaching design through the characteristics of ‘heavy’ learning tasks, more knowledge points, and longer learning time in Chinese middle schools. Based on cognitive load theory, Pang Weiguo (2011) analyzed a variety of measures to reduce the internal and external cognitive load, and paid some attention on how to improve the enthusiasm of cognitive load. Teaching activities in cognitive load theory are designed according to three aspects: individual differences of students, learning materials, and teaching methods. The information processing model by Han Fang (2007) can reduce the negative impact of cognitive load and improve students’ learning efficiency. Information presentation must be combined with the corresponding organizational structure, individual knowledge reserves, and learning materials’ complexity.
2.10.1 Previous investigations/research conducted on cognitive load theory
Wang Bing (2017) studied the material selection of multimedia teaching from three aspects of cognitive load and put forward suggestions for selection. Based on the theory of cognitive load, Liu Weijing (2015) studied cognitive load phenomena in English multimedia teaching and proposed measures to reduce the impact of cognitive load on practical teaching. Tang Xin (2013), through the summary and analysis of the existing literature, especially the research on Richard E. Mayer’s seven strategies to reduce cognitive load, established relevant principles for the scientific design and implementation of multimedia teaching. Tang Xin (2014), based on previous research results, provided references and suggestions for courseware design in teaching practice. Wang Yuanyuan and Shi Qin (2012) studied the technical impact of cognitive load theory on human-computer interactive multimedia teaching and analyzed the influencing factors of cognitive load through practical application. Cheng Zhi and Zhou Tie (2008) studied cognitive load theory qualitatively and applied it to the teaching design process of the effect of distraction, double sense, independent interactive element, and surplus effect, and demonstrated its effectiveness. Chen Liang and Guo Zhao (2006) described the situation of cognitive overload in Mayer’s “nine ways to reduce cognitive load in multimedia learning” and then proposed measures to reduce the cognitive load from the perspective of three theoretical hypotheses. At this stage, the extensive introduction of Internet resources in classroom teaching, students and teachers have a good degree of acceptance, so it is particularly important to study and explore classroom teaching, so as to continuously improve students’ learning efficiency, and put forward measures to reduce cognitive load.
Sun Chongyong and Liu Dianzhi (2013) compared the validity and sensitivity of the three cognitive congruence subjective assessment scales through the practical research of dual task. According to the research results, the second task’s response is better than that of other tasks, and it has good stability and anti-interference. In the measurement of sensitivity, it is found that the scales of subjective evaluation of cognitive load have high sensitivity, and the scale of the second task performed is superior to the scale of the first task that is performed in terms of diagnosis and validity. Through comprehensive experimentation, it was found that the WP scale can measure cognitive load more accurately when the difficulty level is lower than medium. Cai Yanling (2009) described the measurement of cognitive load in mathematical statistics, language teaching, and other fields. Through the study of measurement methods, seven judgment criteria were proposed to test whether the measurement methods were effective, and the accuracy of the physiological index measurement method, subjective measurement method, and behaviour measurement method were explained. Among them, SWAT and NASA-TLX are the two most widely used techniques in subjective measurement. NASA-TLX has higher sensitivity in measuring task complexity and analyzing the factors causing cognitive load difference. In terms of correlation with academic performance, the reliability of NASA-TLX measurement results is higher than that of SWAT.
For the teaching and research of English listening, Xia Ningman (2014) combined audio information with graphics, patterns, and other auxiliary information to test students’ English listening, and explore the changes and influencing factors of cognitive load, so as to improve students’ listening level. He compared the results of a video test and an audio test according to the types of questions, test scores, and types of multimedia materials through practical teaching experiments based on cognitive load theory. He put forward the conclusion that video materials play an auxiliary role in listening. Liang (2011) studied the cognitive load of news listening, optimized the courseware, and proposed the increase of diversified teaching activities to improve the related cognitive load and reduce the overall cognitive load. Jung Chen & Chi Cheng Chang (2009) tested listening comprehension with a language classroom anxiety scale and a cognitive load topic assessment scale on 88 non-language majors and proved that anxiety could increase students’ listening comprehension.
In terms of writing teaching, Zhong Yunxia (2017) put forward the teaching design and measures for each stage of the English writing process based on cognitive load theory and mobile theory. Feng Qiuyi (2017) introduced “flipped classroom + micro class” into English writing classroom teaching. Tests have proved that this kind of teaching mode not only helps to reduce students’ cognitive load, but also improves their writing level. In the teaching of English writing, students should analyze the given materials, reduce their complexity, and eliminate irrelevant cognitive load in them, so as to enhance the students’ ability to analyze the materials and improve the writing efficiency (Liming, 2014).
In terms of English reading teaching, Hu Yanci (2017), based on cognitive load theory, combined with English reading teaching examples, carried out practical research on different strategies to reduce the cognitive load from teaching strategies, implementation steps, and teaching content. He proposed four measures to reduce cognitive load through research, and analyzed the relationship between cognitive load theory and English reading teaching efficiency. Li Xiaoyuan (2013) combined teaching measures with teaching actions, studied the influencing factors of cognitive load theory in reading comprehension, and elaborated the application of different reading tasks and teaching aids in reducing cognitive load, taking students of a certain university as the research object. Li Xiaoyuan (2012) took a senior first-year high school student as the research object, analyzed the difficulties in senior high school English reading materials, and improved the efficiency of reading teaching from the optimization of teaching design. Based on cognitive load theory, Zhou Yufeng (2012) analysed the problems existing in College English reading and studied cognitive load from two aspects of positive and negative effects. Pan Liping (2012) studied the current teaching methods of English reading in senior high school from the two aspects of intensive reading and extensive reading combined with cognitive load theory, and put forward suggestions. Based on cognitive load theory and action teaching theory, Zhang Baoqing (2017) optimized the corresponding reading teaching measures for English majors and non-English majors and put students with different knowledge backgrounds into the cognitive load theory.
2.11 Measurement of cognitive load
Most of the subjective evaluation indices of cognitive load were based on a Likert scale, and most of them were scored at 9 or 7 points (Paas, 2003). The subjective evaluation scale includes the psychological effort to learn new knowledge or complete new tasks, as well as the evaluation of the difficulty of tasks or materials. The higher the cognitive load perceived by individuals, the higher the score on the scale. In addition to the Likert scale, the cognitive load assessment scale developed by Kester (2006) includes six subscales: psychological needs, physical needs, time needs, setbacks, achievements and errors. The final total score is obtained by weighted average of the six subscales. Gerjets (2004) revised the task load index (NASA-TLX) as a measurement tool, which includes the effort of subjects in order to better understand the learning content, the physical and psychological activities required for learning or task completion, such as decision-making, memory, calculation, observation, etc., and the individual’s effort to be familiar with the learning environment navigation need.
Objective evaluation indices include heart rate, pupil size, and skin conductance. Different cognitive load can be estimated by measuring the heart rate of an individual (Paas, 1994). As a useful and objective measurement index, the value of a person’s heart rate will not affect their task completion process, and the measurement results are reliable, effective, and highly sensitive. Under the same conditions, the greater the increase in heart rate, the higher the individual’s tension and anxiety. Eye trackers can also be used to measure the degree of pupil dilation so as to determine the cognitive load (Gog, 2009). Brain imaging technology has been widely used in various fields of psychology. Similarly, its high sensitivity and clear imaging also have a great contribution to the measurement of cognitive load (Hu Naijian, 2010).
Task performance measurement is an objective and direct method to measure cognitive load, that is, to judge the cognitive load brought by the task by measuring the performance of learners in completing a given task. Due to the correlation between workload and performance level, some parameters to measure performance level are often used to evaluate the level of workload. The evaluation index of task performance measurement method is measured by checking the performance of learners in completing learning tasks by the use of performance indicators and time indicators (Paas, 1994).
Cognitive load can be measured in the following two ways:
(1) Performance indicators method
In the measurement of cognitive load, the achievement index is an objective index widely used. Performance indicators, such as memory performance and transfer performance, reveal the cognitive load by analyzing the performance results of learning tasks, especially in multimedia learning. The scores obtained by common knowledge are used to determine the cognitive load.
(2) Time index
Reaction time (RT) is one of the main research methods and techniques to determine cognitive load, and is based on the measurement of reaction time in cognitive psychology or information processing psychology. The reaction time can be divided into simple reaction time, discriminative reaction time and selective reaction time. Simple reaction time reflects the ability to rapidly coordinate functions of human nervous and muscle systems, which is the basic response time. Discriminative reaction time is an additional time of discrimination based on simple reaction time. It stimulates the activities of sensory organs and transmits information processing to the brain through the nervous system. Selective reaction time can be understood as an increase in reaction time on the basis of discrimination. Under certain tasks, discrimination response time largely reflects the size of cognitive load. In the reaction time experiment, the subjects are required to comply with the principle of “speed accuracy trade off”, that is, under the premise of ensuring correctness, the faster the reaction, the better. Since the 1980s, computer software has been widely used to record and collect response time data, such as e-primedmdx} millisecond software inquiry. In addition, many kinds of experimental equipment used in psychological research, such as eye trackers, electroencephalographs, functional imaging, magnetic resonance imaging, computed tomography, pet, magnetoencephalography, and other instruments, all integrate accurate response time recording components into these devices, so that they can record reaction time accurately.
It can be seen that task performance measurement can provide a direct performance index, without additional efforts to establish and record data on behalf of analysts. When measuring the work overload of operators, task performance measurement is very effective. However, it is difficult to distinguish differences between different levels of workload with task performance measurement alone; this needs to be achieved by combining various technologies to achieve exemplary results.
Generally, heart rate and heart rate variability are used to evaluate cognitive load. Heart rate variability analysis is a method used to measure the degree of change in heart rate. It is mainly used to analyse the time series of heart rate and heartbeat interval obtained by ECG or pulse measurement; that is, the phenomenon of periodic change of heart rate in a certain period of time is observed. With an increase in cognitive load, heart rate increases and heart rate variability decreases (Sweller, 2010).
When measuring cognitive load, the specific indicators related to eye activity include pupil dilation, eye blink rate, eye blink interval, fixation times, and scanning path. Pupil size is highly sensitive to changes in cognitive load, making it one of the most accurate physiological indicators to evaluate cognitive load. The larger the change of pupil size, the greater the cognitive load, and vice versa. Fixation time refers to the time taken by a single subject to complete the task. The longer the fixation time, the higher the cognitive load. The distance of the saccade path directly reflects the temporal and spatial characteristics of eye movement. A shorter total distance of the saccade path indicates that the subject only needed a shorter distance to obtain information, indicating that the cognitive load was low.
The specific indicators of ERPs to measure cognitive load mainly include amplitude and latency. Amplitude is the distance from the peak to the trough of the brain wave caused by a stimulus or event, in microvolts, while latency is the time from stimulus presentation to brain wave appearance. The P300 component of ERP detects the after effects of human-computer interaction. It is found that the amplitude of P300 varies with the type of task, which is lower in a cognitive task and higher in emotion-based tasks. In addition, P300 shows shorter latency in cognitive tasks. The shorter the latency, the lesser the cognitive resources consumed and the lower the cognitive load.
At present, physiological measurement also faces some problems, which are mainly manifested in the following three points: the first is the unavoidable invasiveness, which makes the subjects feel the measurement as an experiment and reduces the immersion of the subjects. Even if the least invasive non-contact eye movement measurement sensor is used, the subjects still need to adjust their posture during calibration, which may conflict with the comfortable posture adopted when the subjects perform the task without eye movement measurement sensors. The second is comprehensiveness, that is, whether the physiological measurement method is a true reflection of the cognitive workload. For example, pupil diameter is also affected by changes of light intensity, which contributes to a significant interference to the desired measurement in relation to cognitive load. Finally, different physiological measurement methods reflect different aspects of workload. For example, eye movement indicators reflect more visual-related workload. When task types change, some physiological indicators may not be applicable for measuring cognitive load. It can be seen that each method of cognitive load measurement has its own advantages, disadvantages and limitations. In practical application, a combination of various methods is often used to measure cognitive load.
The measurement of cognitive load often combines task performance measurement with physiological measurement and subjective evaluation of workload. Through the comparative analysis of cognitive load measurement methods, the most widely used and most valid is the NASA-TLX evaluation scale. NASA-TLX is selected as the subjective evaluation index. The operation task is the most important and direct task in the whole experiment. Its completion can directly represent the cognitive load level in the process of task completion. 80% of human information is obtained from the visual channel and therefore the eye activity index can best reflect human psychological response, while cardiac activity analysis and EEG analysis need further research (Chen, 2017).
Because of the complexity and implicitness of cognitive load, its measurement has always presented a difficult problem. We cannot directly observe the process of information processing and cannot directly observe cognitive load. It is, therefore, difficult for researchers to measure the cognitive load of multidimensional construction. However, Western psychologists have explored the measurement of cognitive load from various viewpoints in their research and put forward different methods for measuring cognitive load (Paas et al., 2003).
Research on cognitive load needs a set of measurement and evaluation tools with high reliability and validity. Although different techniques are used in psychology to evaluate the degree of cognitive load, it is still necessary to study the measurement of cognitive load further. Van Merrinboer et al. (2005) pointed out that it is necessary to study the methods of measuring cognitive load, especially the development of measuring tools so that researchers can distinguish changes in cognitive load.
Since Paas et al. (2003) compiled the first cognitive load self-assessment form, Western educational psychology circles have used various methods to evaluate cognitive load. The methods and means of evaluation are also varied, and some of them have used modern scientific and technological means. At present, indirect subjective assessment is the most widely used method in cognitive load assessment. Psychological effort is used to measure the degree of cognitive load. However, the psychological effort is a very general indicator, which only investigates the degree of mental effort students put into learning. Paas (2003, 63-71) is perhaps the most authoritative psychologist in the study of cognitive load assessment. The self-rating scale he often uses, according to Tasir and Pin (2012, 449-465) is as follows:
I put in very low psychological effort in learning or solving problems just now; very low psychological effort; neither low nor high psychological effort; high psychological effort; very high psychological effort.
In studying or solving the preceding problem, I invested: 1. very, very low mental effort; 2. very low mental effort; 3. rather low mental effort; 4. low mental effort; 5. neither low nor high mental effort; 6. rather high mental effort; 7. very high mental effort.
It can be seen from this that there are no specific indicators of his psychological efforts, which are very general and difficult to distinguish. Paas (2003) also admitted that only a few simple problems can be used to assess cognitive load, making it difficult to develop a more comprehensive questionnaire tool.
Deleeuw and Mayer (2008) measured internal cognitive load, external cognitive load, and related cognitive load by using secondary task response time, self-assessment of mental effort in learning (grade assessment) and self-assessment of difficulty of learning materials (grade assessment). Cao Baolong and colleagues (2012) studied the influence of cognitive load on pupils’ WM resource allocation strategies. They used the number of steps used to solve arithmetic problems to measure cognitive load. When solving problems, the cognitive load was often greater than or smaller than that typically used in other situations. Morley and colleagues (2011) studied the effects of material pattern and cognitive load on analogical learning of primary school students and used the number of materials to determine the cognitive load.
Therefore, in research on cognitive load evaluation, the core indicators of cognitive load are not uniform. Different researchers have used different standards to measure cognitive load, and the degree of cognitive load detected is also different. Even if psychological effort is the most widely used criterion for assessing cognitive load, it has no clear definition. Looking at the research literature, the evaluation of cognitive load needs to be further strengthened. It is necessary to establish clear evaluation indicators and compile high-quality research instruments to understand the cognitive load of learners in learning, to provide operational tools for diagnosing the actual situation of learners’ learning load, and to provide a basis for reducing the load on learners (Cao et al., 2012).
Effective teaching and effective learning are the goals of modern teaching and learning. Many things are needed to achieve effective teaching, among which rigorous instructional design is key to effective teaching; cognitive load theory is a theoretical support for informed instructional design to achieve the goals of teaching and learning. Many theories of cognitive load have become the principles of instructional design. The empirical research results pertaining to cognitive load in educational practice have gradually become an important basis for instructional design (Morrison & Anglin, 2005).
Cognitive load theory is the theoretical fulcrum of teaching design. The elaborate design of teaching aims to minimize the external cognitive load brought to students by the teaching organization itself and save students’ cognitive resources as much as possible, which coincides with pursuing benefits in modern education. In the process of learning, students’ psychological investment can also be considered a kind of cost, and, by extension, we should also pay attention to the economic principle of maximizing investment benefits. Many teachers seldom think deeply about the teaching design in the actual teaching process, instead taking classes and coaching in an unplanned manner. This kind of teaching organization process invisibly increases students’ learning load and directly reduces teaching efficiency. Xin Ziqiang and Lin Chongde (2012) clearly pointed out that instructional designers should also eliminate unimportant or dispensable information from their teaching materials.
According to Paas’s (2003) teaching efficiency model and cognitive load’s teaching and research results, teachers should analyze the cost-effectiveness of teaching and learning in teaching design, paying special attention to the cost of in terms of students’ psychological effort, while also minimizing students’ external cognitive load, expanding their related cognitive load, and carefully organizing teaching to maximize teaching effectiveness. Based on cognitive load research, Paas and colleagues (1994) put forward the ‘best teaching efficiency model’ as the goal that every teacher should pursue. In traditional teaching design, many teachers think too much about how to speak well and how to attract students with novelty, but seldom consider what effect the cognitive load on learners will have on learning. The study of cognitive load provides a new perspective for modern instructional design. Teaching design should pay attention to the causes and functions of students’ different cognitive load components, which corresponds to the calls for student-centered education in modern education.
Renkl (2003) believes that one of the classical teaching effects of cognitive load theory is the sample effect. Students’ learning is bound to entail a cognitive load; some cognitive load interferes with learning, and some cognitive load promotes learning. The aim of instructional design should be to reduce that cognitive load which interferes with learning and enhance the cognitive load that promotes learning. Sample teaching is a common technique used to reduce cognitive load. As Paas and colleagues (2018), the experts of cognitive load theory, put it, using well-designed examples instead of solving the same problem is the easiest and perhaps the best way to reduce cognitive load.
According to the theory of cognitive load and its empirical study, the following points should be paid attention to in designing and using examples in teaching:
(1) The learner’s prior knowledge: the level of students’ existing knowledge and experience is an important basis for teaching design. In order to give full play to the supporting role of examples and enable them to support the construction of knowledge in the process of students’ learning, it is necessary to combine examples with students’ existing knowledge, carefully design the examples used in teaching, give full play to the positive role of examples, and prevent the negative effect of examples. The examples given should not break away from the students’ existing knowledge and experience but should play a supporting role. More so, they should not overlap too much with the students’ existing knowledge, as that would have a negative effect. A large number of experimental studies have proved that students who lack prior knowledge have lower learning efficiency in exploratory exercises than in sample learning. Morrison and Anglin (2005) believe that for experienced students, exploratory exercises lead to more psychological involvement than sample learning, which means that exploratory exercises lead to higher levels of cognitive load than sample learning. From this point of view, elaborate design of teaching examples using sample learning methods can reduce students’ cognitive load in the learning process.
Through experiments, Morrison and Anglin (2005) also proved that PBL and case-based learning provide two strategies for instructional design. PBL can provide a wealth of practical content so that students can explore various options, while case-based learning provides a guiding method for students. These findings reveal that in the absence of prior knowledge, it is better to start with sample learning and then turn to a PBL environment in order to gradually increase learners’ psychological involvement and efforts, prevent cognitive overload, and improve learning efficiency.
(2) The type and function of the sample: The design and use of teaching examples should also take into account factors such as teaching content, timing, learning stage, and psychological development level of students. Different teaching examples can be designed according to different situations, and appropriate teaching examples should be used at the best time. To elaborate, different types of teaching examples have different effects on students’ learning at different stages. The design of teaching examples has become a means of teaching methods. Example teaching does not only help students understand the learning content and support their knowledge construction, but can also be used as a training means to help students construct schemata and improve the level of schemata automation, thereby reducing interference and improving learning efficiency.
Kirschner (2009) believed that we could increase the related cognitive load by learning well-designed examples and reduce cognitive interference and overload by exemplar intensive training. As a means of teaching, teaching examples play an important role in directing, guiding, supporting, linking, and promoting students’ learning. But the premise is that the students should further process the teaching examples. If the students neglect the teaching examples in the learning process, the examples cannot play their due role. Therefore, teachers should guide students to refine teaching examples, impart strategies and refinement methods, guide students to extract the important information from examples, analyse the structure of the examples, and link the knowledge units before and after the examples.
From the above, it can be seen that most of the research on the application of cognitive load theory to guide practice focuses on the design of methods to reduce the external cognitive load, which is not directly related to learning. Cognitive load theory is widely used in the teaching design of various media. Cognitive load has become an important factor in the application of research technology in teaching. However, little research has been done on the effects of internal cognitive load and related cognitive load on learning.
2.12 Research on instructional design based on cognitive load theory
Researchers on instructional design based on cognitive load theory mainly focuses on improving the information presentation of learning tasks or materials, so as to reduce learners’ external cognitive load. According to Sweller (2005), six effects should be considered in teaching design to reduce the external load effectively: free goal effect, example effect, problem completion effect, attention dispersion effect, redundancy effect, and channel effect.
There are two kinds of strategies to reduce the internal load: partial task strategy and overall task strategy. Partial task strategy refers to presenting part of the task first, then presenting the rest of the task in turn, and finally presenting the overall task. The sub-goal method proposed by Eiriksdottir and Catrambone (2011) and the segmentation technology and preview technology proposed by Mayer et al. (1999) mainly belong to this kind of strategy.
Strategies to increase the effective load include task variation design and embedded stent design. Sweller (2005) confirmed that the exemplar nature of variation, on the one hand, encourages learners to distinguish similar or related features from unrelated features, thus facilitating the construction of problem schemata. On the other hand, it provides learners with the opportunity to identify similar features and expand the scope of application of examples’ schemata development and transfer. Embedded scaffolding design, that is, when designing learning tasks, embeds scaffolding (scaffolds: design and strategies to support learners’ learning, such as hints, teaching tips, feedback, process worksheets, etc.) to induce learners to engage in cognitive activities related to schema construction and automatization. Choi HeeJung (2004) confirmed that a series of reflective questions or suggestive information were designed in the examples, which could lead learners to self-explain the process of solving the examples. Van and colleagues (2005) confirmed that the process-oriented examples (providing detailed information on the principles and methods of solutions) were only provided with detailed information on the principles and methods of solutions. The process of solving steps to achieve results can promote learners to generate effective load and promote understanding and transfer. Van and colleagues summarized their experimental research on reducing external load in the field of multimedia learning conducted over more than ten years, and pointed out that channel effect, coherence effect, signaling effect, and spatial contig all have an effect on the cognitive process of multimedia learning. The results show that there are three kinds of effects: the guilty effect, the redundancy effect, and the temporary continuity effect (Morozov, 2009).
Mayer defined multimedia learning as learning from verbal forms (such as printed text, commentary, etc.) and images (pictorial forms, such as illustrations, charts, animations, etc.). This dichotomy, being so proposed as the “channel effect” by Mayer, is a narrow definition. In a narrow sense, in multimedia information presentation, speech presented in the form of sound is better than that in written text (Sweller, 2010). This is because when speech is presented in auditory form, multimedia information composed of images and speech can make full use of both auditory and visual channels. The congruence effect means that learners’ learning effect is better when irrelevant materials are excluded as any irrelevant materials will require the cognitive resources of WM and impose too much external load for effective learning. The marking effect refers to the use of marking technology (such as red or blue arrows, hyperlinks, and other technologies) to mark the difficulties, key points, or content structure of learning tasks. Marking can guide learners to quickly search for special information and make it easier for learners to determine which information is relevant. The essence of this approach is to reduce the external load and make more WM resources available to integrate the current information and pre-existing knowledge. In a sense, the consistent effect and the marking effect represent the comprehensive use of the redundancy effect and the distracted attention effect proposed by Sweller (2010). The spatial proximity effect refers to the effect of the proximity of words and images, with similar meaning being better for learning than when the effect when presentation is separated. The temporal proximity effect means that the simultaneous presentation of speech and image is better than their successive presentation.
On the one hand, this allows learners to expend fewer cognitive resources to explore and connect with the image representation associated with speech, thus reducing the external load; on the other hand, it is more likely to encourage learners to connect and integrate speech and image representation, so as to increase the number of words and images. It can be seen that spatial proximity and temporal proximity are the specific forms of attentional distraction. In conclusion, Mayer et al. (1999) specifically supported and expanded the research and provided operational principles for teaching design to reduce external load (especially to reduce the external load in multimedia teaching).
In the rich and colourful experience of daily work and life, all kinds of sensory organs, especially the visual system, in people’s bodies are exposed to massive information impact input. However, the processing ability of our sensory organs is limited, which means that people need to select among the huge amount of information they are exposed to. At this time, attention allows for the selection of information. The existence of attention can select the information which individuals need to process for the human perception system.
Top-down (endogenous) perceptual processing refers to processing based on spatial location or object characteristics, which is related to task goals, related rewards, and even potential threats received by the brain (Maunsell, 2006). In visual tasks, visual attention is controlled at a certain point or region based on the will of expectation and verbal symbol. For example, if we want to buy pure water of a certain brand, we have expectations for this brand’s purified water, and we will have various dimensional images in our minds. Therefore, when we enter the supermarket, we will not go back and forth to choose, but go straight to the pure water in mind, looking for the purified water we want and ignoring the visual input of other items. When we talk about top-down perceptual processing, we will associate with or imply that this results from the observer’s intentional control. That is, it is the result of choice and is entirely determined by will.
Posnernyder’s (1975) experimental research clearly describes the top-down selection processing: before each experiment, the observer will be given a hint, that is, to tell them the possible position of the upcoming target. Such a prompt is presented by the arrow or number that appears with the target, so as to remind the observer of the possible position of the target stimulus (Theeuwes, 2007). The research shows that the observer can judge the position of the target stimulus more quickly and correctly, and reduce the false judgment rate, which confirms that the top-down selection process is a positive will process.
The expectation paradigm (cue paradigm) uses cues to study boundary condition attention controlled by top-down and bottom-up perceptual processes (Theeuwes, 2006, 2007). Almost all visual theories assume that individuals use top-down perceptual processing to search for objects (Mielleret, 2003). More generally, if you tell the observer that the upcoming target stimulus is red, the individual will spend a shorter time in judging the response to the red target stimulus. Top-down perceptual processing can allow the individual’s attention to focus quickly. The premise of fast concentration is to judge whether the object is the target stimulus. There are sufficient empirical data to prove that top-down perceptual processing can affect the individual’s choice of objects. For example, if the observer understands the characteristics (color, shape, brightness, direction) of each of the target object, he will pay special attention to these aspects in order to speed up the search (Treisman, 1988).
Bottom-up (extrinsic attention) is the result of the external physical characteristics of stimuli, such as a moving stimulus in a still object. Individuals in the environment will constantly look around and use the input of visual effects to guide their behaviour. For example, when people are in a street full of neon lights, they will unconsciously notice the jacket of road safety workers wearing fluorescent orange or the billboards moving along the road. This is precisely because the bright physical characteristics of external stimulation will attract the individual’s attention automatically.
Bottom-up perceptual processing is a passive automatic processing mode. This kind of automatic mode is caused by the prominent physical characteristics of a visual input stimulus, which is different from other surrounding stimuli. This can be traced back to functional integration theory, which shows that in the early stage, some simple visual features, such as colour, edge direction, brightness, or motion direction, are processed by cortical vision. Of course, this is also related to other features of the observer, such as the observer’s emotion (joy, anger, etc.) and experience when seeing the stimulus. The result is that visual selection is driven by the individual experience formed by the observer’s last judgment event. That is, judgment initiation is generally considered to be bottom-up. In an experiment, when the observer tries to search for an object, if there is a stimulus that has appeared the previous time, he will choose to continue to use this stimulus as the target stimulus in the search task. In addition, content-driven WM in searching for other objects is also bottom-up. In the experiment of keeping the memory of another object while looking for a specific target object, the results show that the object left in the memory gains more attention than the object that does not.
Stimulus-driven selection theory was proposed by Theouwes (1991). This theory’s premise is that when attention is divided into the visual field, pre-processing is a feature of the bottom-up driving stimulus field, and the initial selection is completely based on bottom-up processing. Only when a specific object is selected will its characteristic identity be activated. For example, we choose a more prominent object because it has colour, brightness, or a unique shape compared to other objects around it. The former attention analysis only allows individuals to detect that the image’s attributes of the visual input object are obviously different from those of the surrounding images’ attributes, such as colour, shape, brightness, size, and so on. In other words, pre-analysis can reveal the characteristic differences of objects (i.e., significant elements), and can be analysed from any dimension. It is assumed that the individual’s attention is automatically transferred to the object with significant local or global features. After the object is focused on, and the attention is shifted to the position of the prominent element, the prominent element is activated.
Stimulus-driven selection theory has several important hypotheses. First, when the attention is distracted from the display, the difference calculation of local features is carried out in a bottom-up way, which is beyond the control of will. Because the presupposed signals can only be used to calculate the differences in the object characteristics, the top-down knowledge (such as the observer looking for a red square) cannot affect the pre-processing process. Once the most visible square is selected, its identity becomes useful, and top-down knowledge comes into play. Suppose the target is not found after automatic selection according to the feature difference signal; in that case, the top-down processing (after the automatic selection of the object) will withdraw the attention from the most significant position to select the zero-mark object. It is assumed that the initially given information scanning is basically stimulus-driven, and the initial information scanning functions to pre-analyse the environment, and then gradually reduce the pre-analysis. With this repeated process, spatial information is considered to be controlled from top to bottom, which affects the information passing through the brain during the initial scan. Therefore, the theory assumes that the advance analysis is carried out in a specific area. This is because the pre-analysis is limited to a specific domain; the degree to which attention is transmitted determines the occurrence of attention capture. When attention is spread widely, all items in the field of vision can be searched visually at the same time, and any related and unrelated objects will be automatically selected. However, when the attention window is relatively small, the items outside the attention window will not attract the individual’s attention. The theory claims that the size of the attention window is controlled from top to bottom, and the top-down control in the attention window cannot exclude the attention captured by the most significant features (Treisman, I988). It is important to realize that the search is serial or partially serial (e.g., in a federated search), and when the task needs to pay attention to the window set to contain a relatively small domain, this means that saliency calculations for that region are excluded.
2.13 Research status of the PBL model
Barrows (1986), the founder of Problem-Based Learning (PBL), thought that PBL was both a course and a learning method. As a course, it requires carefully selected and designed problems to enable learners to acquire key skills by solving these problems; as a way of learning, it requires learners to use specific methods to solve problems and solve problems in learning, he wrote. Mayer et al. (1999, 638-643) thought that PBL was a kind of teaching strategy: in the process of learning knowledge and developing problem-solving ability, creating meaningful, situational, real-world situations for students and provide them with resources, guidance, and guidance. ” Barrows and Mayer thought PBL was a new teaching mode. This kind of teaching mode put students in a chaotic and ill-structured situation and made students become the master of that situation. It allowed students to analyse problems, learn the knowledge needed to solve the problems and cultivate learning interest and initiative.
According to the definitions of the PBL model by the above scholars, I have combined the definitions of Mayer and Barrows. For this thesis, the definition of the PBL model is: in a real situation, teachers guide groups of students to find problems and solve problems in the process of learning. The PBL model emphasizes the authenticity of the situation and the importance of group cooperation.
2.14 Review of the theory of PBL
From the existing research, researchers believed that PBL could be a kind of teaching strategy, teaching concept or teaching method. PBL was not only understood as a course, but also a process, and also a method to let students participate in learning courses through learning real or close to real situations or cases. In this thesis, as a teaching concept, PBL creates real problem situations for teachers and highlights the characteristics of problem-driven learning. Students analyse and solve problems through autonomous and cooperative learning. In this process, students learn the scientific knowledge behind the problems and promote the development of problem-solving ability, cooperative communication ability, and autonomous learning ability. In other words, it is a kind of teaching concept that fully embodies learning at its centre.
Based on the connotation analysis of PBL and researchers’ research on PBL, the elements of PBL are determined as follows:
(1) Problems
Problems in PBL are different from those in conventional teaching. They can be classified according to different classification standards, as follows:
- Practical problems: these are derived from real situations in actual production and life, such as “how does acid rain form?”.
- Theoretical problems: these point directly to the knowledge content in the textbook and reveal the principle of knowledge. There is no specific situation, such as “how is sulfur dioxide converted into sulfuric acid?”. According to the structure of the problems, the problems are divided into the following categories: Well-structured problems: well-structured problems are generally closed problems with a clear and fixed answer. Students do not have to design their own solutions to such problems, such as “what is acid rain?”. Poorly structured problems: poor structure has less relevance and teaching effectiveness than for problems with good structure. Generally speaking, the problem of poor structure is open-ended, and there is no single, definite answer. Students need to collect data and design solutions to solve the problem. However, the problem of poor structure makes it easier to promote the development of students’ abilities in some aspects, such as “how to prevent and control acid rain?”.
According to the degree of openness, problems can be divided into the following categories:
- Core problems: The upper level of the framework problems directly point to the core quality of the discipline, serving the lifelong development of students, with a large degree of openness, such as “how can one understand sulfur and its compounds from the process of volcanic eruption?”.
- Framework problems: They are used to frame the scope of learning and guide students to study and explore deeply, such as “what transformation can be realized for sulfur-containing substances with – 2, 0 and + 4 valence?”.
- Driving problems: The framework problems are challenging, and the problems can drive students to carry out what is the guiding problem of learning, such as “why is there such transformation between these materials? What is your basis for this answer?”.
- Content-based problems: These solve the basic problems of driving problems, directly point to factual knowledge and basic skills, and lay the foundation for students to develop higher-order thinking ability, such as “what kind of reagent should be chosen for a reaction” or “What are our common reductive reagents?”.
(2) Teachers
Under the concept of PBL teaching, the role of teachers has changed, so that this is different from traditional teaching.
- As “designers”, teachers follow the guidance of the PBL teaching concept and design problems according to the characteristics of PBL problems, so as to carry out relevant learning activities under the teaching concept.
- As “organizers”, teachers organize students to carry out learning activities through problem-solving, control the learning rhythm and ensure the smooth progress of learning.
- As “guides”, in the process of problem-solving, teachers: give macro guidance to students to promote students’ learning activities; supervise students’ learning and give appropriate and timely guidance; guide and inspire students to put forward their own views, rather than directly provide answers to problems.
(3) Students
Similarly, under the PBL teaching concept, the role of students has also changed. Compared with traditional teaching, there are great differences, which are exemplified in the following aspects:
- As “cooperators”, from analyzing problems and collecting data to solving problems, members exchange, share information, and cooperate with each other.
- As “explorers”, in the process of problem-solving in PBL, learners are also undertaking a process of inquiry. Cooperative learning among members of the group and autonomous learning of each member function to explore and solve problems and give full play to the individual subjective initiative.
(4) Learning style
Learning activities under the PBL teaching concept are carried out in the form of problem-solving. Students usually cannot solve problems by themselves, and, therefore, both group cooperation and task division are needed. The whole process of problem-solving embodies a meaningful discovery through the learning method. It mainly includes the following learning methods:
- Cooperative learning: students take part in the responsibilities of the group in the learning process, and carry out learning with the group members in a diversified way such as discussion, practice, or teaching others.
- Autonomous learning: in PBL, students need to be self-motivated, set learning goals, and conduct self-directed learning. If the autonomous learning of each member of the group does not occur, cooperative learning will be impossible.
- Inquiry learning: in PBL, students solve problems by asking questions, formulating hypotheses, and collecting evidence.
2.14.3. Characteristics and studies of PBL
There are two types of research on problem characteristics and learning: one is to understand the meaning of specific problem features more deeply. The other is to investigate how specific problem features affect learning by students. It is found that although students can clearly distinguish simple problems from difficult problems, it is difficult for them to distinguish between poorly structured problems and complex problems (Soppe et al., 2005). In other words, from the perspective of students, the definition of the characteristics of the two problems is not clear.
The research by Soppe et al. (2005) focused on the familiarity of the problem and its influence on learning. The researchers used a self-designed questionnaire to test students’ perceptions of problem familiarity. They evaluated this and its learning effect (taking “the number and quality of summarized learning points,” “academic achievement,” and “self-study time” as the evaluation criteria). The results showed that compared with the students who were not familiar with the situation, the students in the familiar situation group were more familiar with and more interested in their problems.
The above research expands people’s understanding of the concept and research methods of “problem characteristics.” It also provides some methodological support for my study – phenomenological research is suitable for distinguishing problem features. At the same time, experimental rules are more suitable for investigating how specific problem features affect learning presentation.
There are three key features of PBL:
(1) Practicality
PBL is learning with real problems at the core. Curriculum design focuses on practical problems rather than subject knowledge, encouraging students to solve problems by acquiring knowledge related to these practical problems.
(2) Autonomy
Throughout the whole process of PBL, students’ personal participation and practice, from facing the problem situation to analyzing and solving the problem, students’ cooperation and division of labor are required. Students must make their own plans to collect data and actively participate in various activities.
(3) Cooperation
PBL students carry out learning activities by solving real problems, but these problems can be complex. Students share information, communicate with each other, deal with complex problems together, and analyze and solve problems through cooperation and sharing the workload.
As a theoretical model, (PBL) was developed by Barrows. Later, the achievements of the PBL model in the medical field caused other fields to follow suit. After reviewing the relevant literature on the PBL model, we can make the following classification:
- Theoretical research on PBL
This kind of literature mainly studies the theory of PBL and combines it with other cognitive load theories. On the one hand, there are not only many theoretical monographs but also many journal papers. For example, the introduction to PBL published by People’s Publishing House (Huichun, 2013) emphasizes the methods of finding, discussing, solving, and dealing with problems in medical education. In another journal paper, Zhang and colleagues (2008) used the theory of constructivism to explain the PBL model and analyzed the theory of constructivism embodied in the PBL model. Zhang and his colleagues think that PBL teaching is mainly affected by four aspects: problem design, teacher factor, student factor, and environmental factor, among which problem design is the most critical factor. Theoretical research on PBL explains the theoretical basis of the PBL model and provides support for the application of PBL.
- Practical research on PBL
Since the origination of the PBL model, the most studied literature in PBL practice is its application in the medical field. Later, with the continuous development of the PBL model, more and more people have applied it in their own field of teaching (Zhang, 2008). In this dissertation, related papers that apply the PBL model to chemistry, information technology, and other subjects are presented. For example, “Research on the problem-based high school chemistry teaching design” and a “Central China Normal University’s dissertation“. Research on the design and practice of information technology teaching centred on problem-solving has been undertaken (Mayer et al., 1999) (e.g.). However, the PBL model has not yet been fully applied to the field of Chinese education, especially in Chinese reading. Only a few studies have been undertaken on the application of PBL in Chinese text reading and Chinese teaching. An example is Han Fang (2007) which applies the PBL theory to after-school exercises. Therefore, in the field of Chinese reading, it will be a new attempt to apply PBL mode to the whole book reading.
Five basic characteristics of the PBL model can be identified:
- Focus on the problem of poor structure
PBL should always focus on problem-based and problem-solving aspects. In his educational psychology, Zhang (2008) divides problems into “well-structured problems” and “poorly structured problems.” He thinks that the logical relationship of well-structured questions is simple and that the answers can be obtained according to a fixed thinking mode. However, there is no fixed pattern and no fixed answer in the process of solving ill-structured problems, and the problem emphasized by PBL mode is the ill-structured problem. For students, this kind of problem can mobilize their imagination and promote their thinking so that they can gain more from solving this sort of problem. The PBL model emphasizes the problem as the center; that is, it emphasizes the problem with poor structure as the center.
- Student-centered
PBL emphasizes the student-centered aspect, which is a vivid interpretation of humanism and constructivism. Humanistic psychologists emphasize that learning is a process. Learning should take students as the main body. The task of teachers’ teaching is to create a situation that is conducive to the development of students’ learning potential so that students’ potential can be fully realized (Huichun, 2013). ‘Constructivist psychologists stress that everyone has a different understanding of knowledge in learning. That means that every student will have a different understanding of the same thing since students’ learning is based on their own experience, so they urge that teachers should attach great attention to learners’ subject position in the learning process. In PBL mode, students are always the main body and cannot be replaced by teachers. Teachers should therefore change the traditional “indoctrination” teaching method. The main subject of problem-solving is not teachers, but students. The PBL model always emphasizes a democratic and harmonious relationship between teachers and students. That is, in the process of getting along with the students, it is a kind of friendly relationship of equal dialogue. In the process of equal dialogue, teachers and students take the problem as the center, and teachers help students solve the problem.
- Learning based on real situations
Situational learning theory holds that when learning takes place in a meaningful context, it is the most effective. Truly complete knowledge is obtained in a real learning situation where learning is a social process and knowledge is created by everyone in a particular setting. Because the PBL model originated from clinical medical education in medical education, the problems emphasized in the PBL model are all derived from practical situations.
- Diversification of evaluation subjects
In PBL mode, the main body of evaluation is not only teachers but also the students themselves. In the traditional classroom, teachers are the evaluators of students’ learning, and such evaluation subjects tend to work on their own, which cannot objectively evaluate students’ learning achievements. In PBL mode, students not only make self-assessment in learning but also make a mutual evaluation in the form of group cooperation. Furthermore, PBL teaching evaluation is considered from the acquisition of students’ knowledge, learning interests and attitudes. Whether demonstrated through an improvement in learning ability, the situation of group cooperation in the learning process represents the final product of students’ learning. Compared with the traditional teaching evaluation based on knowledge evaluation, PBL teaching evaluation can evaluate students from all aspects and from multiple perspectives.
- The integration of subject content
In PBL teaching, students have no fixed mode and answer in the process of solving problems because the problems they address are ill-structured ones in real situations. They can only seek knowledge and approaches that can solve the problems. When students are faced with ill-structured problems, they can get answers from all the knowledge they have learned, and they can also achieve interdisciplinary communication and learning to the greatest extent.
Based on his “learning by doing” theory, Barrow carried out in-depth research and made improvements and developments to his model of learning. Finally, he put forward the basic concept of PBL and further designed the four basic stages. Some books on PBL specify these as: determine the purpose, make the plan, plan implementation and evaluate the result (Xiang, 2007). Somewhat confusingly, in English, project-based learning and problem-based learning are both referred to as PBL. In our normal teaching process, these two methods are complementary. Problem-based teaching is widely used in many countries and regions, for example in primary and secondary education in the United States (Peters, 2015) and in many vocational secondary schools in Germany (Chen, 2016). Usually, before or at the beginning of class, students are divided into different groups, and the tasks are allocated. In the classroom, teachers only need to give students tasks, and students will then discuss these in groups and develop, design, undertake and complete the tasks assigned by teachers. In problem-based teaching, students actively participate in the classroom, truly become the main body of classroom teaching, and learn real knowledge and skills.
Chen Wenjie of Guangzhou Preschool Normal School, Guangdong Province, in the implementation and research of PBL teaching mode in teaching in secondary vocational schools, mainly focuses on the motivation of students. This first includes students’ guidance to solve problems, reasonable grouping, team cooperation, practical exploration of teachers and reasonable arrangement of teaching links, and implementation of teaching. The second focus analyses the advantages of PBL teaching in flash classroom teaching in secondary vocational schools, such as: stimulate students’ awareness of active learning, cultivate students’ ability to analyse and solve problems, improve practical ability, enhance creative ability, and so on. The third focus is on the PBL teaching mode in classroom teaching which should pay attention to several points. Teachers should not only be familiar with flash knowledge, but also have a sense of innovation and a creative spirit. On the other hand, students should manifest strict logical thinking, be able to grasphe classroom, and solve the problems in the classroom. For students to actively cooperate with the teacher, they should take the initiative to open up their minds, obey the teachers, and participate in group collaborative learning.
Zhou Fengying’s (2014) article mainly focuses on how to improve students’ ability to analyze and solve problems. It is emphasized that instructors should make use of the knowledge structure and rich knowledge connotation in animation design and production to provide students with creative space and communication opportunities. Students are encouraged to manifests the ability to conjecture, think, and solve problems in practice.
Of the above two flash classroom teaching researchers, Chen Wenjie used PBL teaching to guide students to solve problems, stimulate students’ interest in learning, cultivate students’ ability to analyze specific problems and think about solving problems, and cultivate students’ innovation ability in the learning process. This teaching method is appropriate for this thesis and I will focus on the use of a flash teaching process in this study, to cultivate students’ hands-on ability and rigorous logical thinking ability. Zhou Fengying (2014), through encouraging and guiding students to guess, make reasonable inferences, imagine boldly, and demonstrate other aspects to cultivate students’ thinking training, so as to improve the secondary vocational students’ ability to learn, is also suitable for use in my study. I will penetrate into the teaching and making of a propaganda film with a flash so that students can reflect on themselves during biology learning. I chose Zhou’s works while making this film because his pieces are unique, novel, and creative, making his work more appreciated.
The Internet-based PBL research center of the Illinois Mathematics and Science Academy (IMSA) has been engaged in basic education research since its establishment in 1993. Since the establishment of the center, thousands of educators from different regions have participated in various activities which the research centre has organized. Through continuous practice and optimization, the PBL model, which was originally only used in the field of medical education, has undergone changes for its optimization into a teaching mode which is consistent with basic education. A successful example of the application of the model is in middle school. IMSA’s PBL model is a service model for teaching and learning, which is different from the traditional teacher-based or student-centered theories. In this mode, teachers and students are equal participants. The model is based on questions, which enable students to acquire adaptive professional knowledge. The cognitive level and ability requirements of this knowledge are far higher than the knowledge and basic skills acquired under other, conventional teaching activities. The adaptive professional knowledge not only represents the basic level of cognition and ability, but also can be transferred to the process of solving new problems through learners’ metacognitive practice, thus cultivating students’ problem-solving ability and creativity. At the same time, the front-line teachers who participated in the seminar on the application of IMSA’s PBL model gave good positive feedback, and they clearly pointed out that PBL was the key to the success of IMSA. On the one hand, the use of the model has a strong role in promoting their own professional development and their students’ learning; on the other hand, it has made teachers and students undergo an important change in action and thinking. Through more specific and practical teaching methods, the classroom has become an activity place for learners to build their own knowledge system. All in all, IMSA’s PBL model puts forward certain requirements for students’ cognitive level and teachers’ professional development. Combining with the current actual situation, the teaching staff guides students to participate in a diversified talent team by designing problem situations, arousing the participants’ multiple knowledge fields and different thinking modes. This is achieved through the stimulation of problem situations and it stimulates the representation and practice of learners’ metacognition by solving one or a series of problems originating from the complex real world. With the help of information collection and discrimination, group communication, evaluation, and other ways to cultivate students’ higher-level thinking consciousness, real meaningful learning is the result.
In the past 50 years, the PBL teaching mode has been expanded and improved upon through practice, and gradually developed from a naive to a relatively mature state. In the ERIC pedagogy full-text database, the keyword “problem-based learning” was searched, with the time period from 1966 to 2019. More than 5000 records can be retrieved, including various books and journals. The research content also gradually transitions from the basic theory of PBL teaching to its specific applications and optimizations in a range of disciplines. As the PBL teaching mode has gradually become more mainstream, more PBL Research Centers have also been constructed, such as the New York City Education Entrepreneurship Company and Delaware University. These institutions’ PBL websites provide a good platform for researchers to learn, communicate and grow. To sum up, different scholars and teachers in countries have studied and explored PBL from different perspectives and levels, including not only theoretical analysis and research, but also practical verification and inquiry. Generally speaking, PBL has been studied abroad from the roles of teachers and students, implementation links, evaluation methods and other aspects (Ress, 1984). The research results are relatively mature and diversified, providing rich learning resources and a good communication platform for educators and learners.
In 1986, Shanghai Second Medical University and Xi’an Medical University became experimental units. They took the lead in applying the PBL teaching approach to daily teaching, which attracted the attention of other Chinese universities after obtaining positive feedback. Subsequently, China Medical University and Beijing Medical University also applied PBL to basic education courses, experimental courses, and clinical science and achieved encouraging responses in practice (Feng, 1986). With the successful application of PBL teaching in the medical field, its characteristic teaching mode has also attracted extensive attention in the field of education in China. Its development stage can be roughly divided into three stages. In the first stage, many researchers translated and studied PBL monographs. These works often systematically introduce the origin, theoretical basis, meaning and characteristics of PBL, laying a solid foundation for the application of PBL teaching in China. For example, Xiaoqun and Li Xiaoping defined Problem-based learning as making learning easy and interesting and Fan Wei’s defined teaching and learning of problem-solving as a method of interdisciplinary collaborative learning In the second stage, on the basis of a now relatively mature theory, combined with the prevailing situation with education in China, different forms of PBL teaching were studied. Such research was often carried out from the following perspectives: the change of learning objectives, the discrimination between problems and their causes, and the upgrading of evaluation methods. Under the condition of educational philosophy and on a theoretical basis, it brought different enlightenment for the implementation of education reform in China by updating the hypothesis paradigm, the role of teachers and students, and the learning situation itself. The third stage, combined with different actual situations, selects the appropriate PBL teaching mode, optimizes it and applies it to a specific subject. This kind of research often selects the appropriate PBL teaching mode according to the rules of different disciplines and the actual situation of a particular teaching environment. It also designs the PBL in order that it can be modified continuously through the practice of classroom teaching. Different dimensions can be chosen to check the teaching effect, and explore the application of a particular PBL teaching mode within the discipline teaching. To sum up, research on PBL teaching in China has made some significant achievements. At present, the theoretical system is relatively good, but the practice of specific disciplines still needs to be improved. Because the ultimate goal of students’ learning is to become a complete social person, students need to use the knowledge they have learned to solve the practical problems encountered in work and life. However, the courses that students study in school are well-regulated, which leads to the current situation of taking theoretical knowledge as the main body and separating knowledge from the application. PBL emphasizes that teaching should take problems as the main line, start from solving practical problems, integrating practical operation and theoretical knowledge, and evaluating and summarizing the validity of students’ learning from various angles.
Although research on PBL in some countries is relatively mature, scholars have not clearly defined the concept of PBL. The following definitions are more representative: Barrows, founder of PBL, thinks that “PBL is not only a course but also a way of learning. As a kind of curriculum, it puts forward higher requirements for teachers to select and design problems, and for learners to have the ability to acquire key knowledge and also develop in solving problems, autonomous learning, and cooperative inquiry. As a way of learning, PBL allows students to solve problems through the use of systematic methods” (Gedrange, 2013). Gedrange holds that PBL is a learning method in which students learn knowledge and master skills by participating in the solution of real problems. Other scholars think that PBL is a teaching method and strategy. For example, Schwartz believed that “PBL was a teaching strategy, which provides resources and guidance for students by creating real-world situation problems, so that students can acquire knowledge and develop problem-solving ability” (Schwartz, 2015).
From the perspective of information processing, researchers believe that problem-solving is a goal-oriented cognitive process. Individuals form problem-solving strategies by processing, transforming, and integrating old and new knowledge to achieve the goal state (Pang Weiguo, 2009). Generally speaking, problem-solving has three basic characteristics: (1) tagging orientation, that is, individuals must have a goal state when solving problems; (2) subgoal decomposition, that is, when a problem cannot be solved in one step, it needs to achieve the goal state through sub goal decomposition gradually; (3) the application of the operator, that is, the application of problem-solving strategy in the process of an individual realizing the transition from the initial state to the target state (Chen Qi, Liu Lude, 2007).
Learning classification theory tends to put problem-solving into the hierarchy of different learning types, defines problem-solving from the perspective of learning results, and believes that solving problems must be solving new problems. Its representative, Gagne (1985), pointed out that problem-solving is to integrate rules and concepts into higher-level rules, and then apply them to a specific situation. The theory emphasizes that in solving problems, individuals need to integrate their own concepts and rules, so the usability, identifiability, and stability of existing knowledge in individual cognitive structure will affect the result of problem-solving; On the other hand, once the problem is solved, the high-level rules generated in the process of solving the problem will be assimilated into the original cognitive structure. When the individual encounters similar problems in the future, they can react quickly.
(1) Creative problem-solving
If individuals expand the concept of problem-solving to include the application of various algorithms to solve problems, or to solve problems with known or memorized programs, then not all problem-solving contains creative elements. Only those poorly defined open-ended problems without a unique and correct answer can mobilize the individual’s creative thinking (Sternberg, 1982); Mumford, based on this concept, (Brop, 2006) holds that creative problem solving refers to the process of seeking unusual creative solutions for the purpose of solving problems.
(2) Cognitive process involved in creative problem solving
Creative problem solving is a kind of advanced and complex comprehensive creative activity, involving a variety of cognitive processes. In this regard, most of the existing studies have investigated three aspects: divergent thinking, convergent thinking and associative processing (Lee & Therriault, 2013).
Guilford (1967) contrasted divergent thinking and aggregative thinking in his three-dimensional intelligence model and emphasized that divergent thinking was an important creative process. Divergent thinking is a cognitive thinking process that generates many ideas or problem solutions for a given stimulus (Gruber & Wallace, 1999). Divergent thinking tasks (such as unconventional use test) were first used to test the individual’s concept generation, and then gradually developed into a basic method to study creativity. In this kind of task, fluency, originality, and flexibility are generally used as the evaluation indices of creative performance (Plucker & Renzulli, 1999).
In order to get the correct solution, Brophy (1998) proposed that PBL was the only way of thinking. Some researchers believed that there was an opposition between convergent thinking and creativity (Guilford, 1967); others suggested that convergent thinking was also a side of creativity (e.g., Brophy, 2000). Compared with divergent thinking, there has been less research on convergent thinking in the field of creativity. The aggregate thinking training of creativity requires problem solvers to break the thinking pattern and seek original solutions from unusual perspectives. For convergent thinking tasks, distant association tasks, and insight tasks, researchers usually focus on the appropriateness or quality of answers (Brophy, 2000; Guildford, 1967).
Some studies have explored the differences between divergent thinking and convergent thinking, pointing out that they may contain a common cognitive framework, namely associative processing. Theories have pointed out that the creative process was a process far away from the association. In this process, individuals activated their own concepts or ideas in cognitive structure, reorganized and integrated them, and then produced original products. The activation and extraction of the concept of distance support divergent thinking, while the integration and association of the concept of distance support the convergent thinking.
(2) Evaluation of creative problem-solving performance
As mentioned above, researchers have used different creativity evaluation indicators when examining different aspects of creativity. For example, fluency, originality, and flexibility were generally used as evaluation indices in divergent thinking (Plucker & Renzulli, 1999); suitability or quality (Brophy, 2000; Guildford, 1967) were generally used as evaluation indices when investigating divergent thinking. In the study of creative problem-solving, researchers usually formulated a new evaluation system according to their own research purposes, combined with the above two kinds of evaluation indicators.
For example, Reiter Palrnon et al. (1997) put quality (i.e., the logicality and feasibility of the answer, meaning “suitability”) and originality (i.e., the logicality and feasibility of the answer) in the research on the influence of problem construction ability on creative problem-solving. That is, the uniqueness of the answer and breaking the limitation of the situation) and creativity (i.e., the average score of quality and novelty) were used as the evaluation indices of creative problem-solving. When Reiter Palnon et al. (2009) studied how task types affect creative problem solving, they further improved the evaluation criteria, using quality (i.e., the integrity and effectiveness of the answer, meaning “suitability”), novelty (i.e., the uniqueness of the answer, the thinking structure of imagination and its reaction) and fluency (i.e., the number of answers), indicators of creative problem-solving performance.
PBL was seen as a kind of teaching and learning mode based on the constructivism learning view and situational learning theory. There were many different definitions in the existing research, which can be roughly summarized into the following three categories: type 1 thinks that PBL is a method of information processing or cognitive construction. For example, Barrows (1986) defined PBL as “the process of understanding and solving problems, involving the mastery of professional skills. Vernon and Blake (1993) think that PBL is a kind of teaching method to cultivate students’ problem-solving ability and knowledge skills based on problem-based situation. In type 3, PBL was regarded as a teaching model to teach students learning methods. For example, Uden and Beaumont (2006) pointed out that “PBL includes problem-solving activities, critical thinking exercises, cooperative learning and independent learning, which was beneficial for students to connect with problem situations and construct new knowledge”.
When designing problems, instructional designers often rely on their own experience or put forward some problem design models based on relevant cognitive and learning theories. For example, Dolmans et al. (1997) based their work on constructivist learning theory and related empirical research. Seven principles of case design were summarized: imitating real life; guiding cooperative learning; encouraging knowledge integration; motivating learning; adapting to students’ prior knowledge; having appropriate complexity; and structure, and conforming to teaching standards. Hung (2006) proposed the 3C3R model of problem hypothesis in PBL. He considered that the three core components of problem design are content, context and connection respectively corresponding to appropriate hit and sufficiency of knowledge content, contextualization of knowledge and integration of knowledge.
(3) Cognitive processing model of problem construction
Mumford et al. (1994) studied the first step of problem-solving, problem construction, and proposed a cognitive processing model to describe problem construction. The model considers that problem construction affects individual creative problem solving by acting on problem representations. Problem representation is a kind of schematized or classified knowledge extracted from past problem-solving experience, including the following subcategory information: (1) the goal or results corresponding to the problem-solving effort; (2) the key information necessary to define and solve the problem; (3) the procedure and operation of solving the problem; (4) the constraints. Mumford et al. hold that individuals can activate problem representations in the cognitive schemata by focusing on the cues of situational events. When the complexity and diversity of contextual cues increase, more problem representations can be activated accordingly. However, when multiple problem representations are activated, individuals need a method to select them. The most direct and commonly used strategy is to choose the problem representation with the highest activation level because the selection strategy takes the least time and effort – this usually happens when there are many similarities between the problem situation and the existing problem representation. In other words, more abundant situational information with low consistency with existing knowledge or experience makes is easy to activate more problem representations; when the consistency of context information with existing knowledge or experience is high, individuals are more inclined to automatically extract the most familiar problem representation, so as to make the most direct response to the problem by using existing experience.
2.14.5. Cognitive load and problem solving
As mentioned above, when the cognitive load is high, that is, when multiple information needs to be processed at the same time, WM will have to treat these items of information as discrete fragments, and there will be no remaining cognitive resources to process other information. When the cognitive load is low, there will be enough WM resources for information processing. In general, when WM needs to process a large number of discrete pieces of information, individuals have little chance to solve problems creatively (Godsole, 2013).
Santanen (2002) proposed the cognitive network model of creativity and pointed out that creativity was a long-distance connection process between multiple discrete elements. The formation of new connections is negatively related to cognitive load. In other words, a high level of cognitive load will hinder information processing, which will make it more difficult to produce the connection of distant concepts and reduce the creative performance of individuals. The research of Youmans (2007) showed that when designers suffer from high cognitive load due to excessive information processing, they were more likely to have fixed ideas in design. Similarly, the study of Baumeister et al. (2007) also found that cognitive load will pre-empt WM resources, leading to the reduction of creativity. It can be seen that the improvement of cognitive load will inhibit the individual’s problem-solving performance.
Based on the literature discussed in this section, Chapter 3 of the thesis will analyze the literature in order to optimize cognitive load in the teaching of science education concepts.
3 Methodology
This thesis focuses on the cognitive structure of students, and under the guidance of cognitive load theory explores the teaching path to promote the construction of students’ scientific concepts and verify the teaching effect of these methods. Based on the theory of cognitive load (Sweller, 2010), the thesis investigates the present situation of science education concepts. In accordance with the theory of cognitive load, and according to the characteristics of the teaching of science education, this thesis puts forward teaching strategies to optimize cognitive load in the teaching of science education concepts, and formulates specific teaching cases for practical teaching in China. By analysing data on students’ biology achievement before and after a teaching intervention, students’ mastery of conceptual knowledge after class and their evaluation of material difficulty and psychological pressure, this thesis examines the role of teaching of science under the guidance of cognitive load theory in building scientific education concepts for students. It also evaluates cognitive load-based conceptual teaching. It examines whether the teaching of science concepts can reduce students’ cognitive load, help students to understand scientific knowledge more deeply and form a scientific knowledge system.
Under the guidance of cognitive load theory, this thesis explores the teaching path of optimizing students’ cognitive load and promoting concept construction in the process of high school science education, and verifies its teaching results. The main research content is as follows:
- Investigation and analysis of the present situation of the teaching of science education concepts in senior high school based on the theory of cognitive load.
- Based on the theory of cognitive load, a case study method is used to design questionnaires for teachers and students to understand the teaching and learning situation relating to scientific education concepts.
- Analysing cognitive load and its influencing factors on the teaching of scientific education concepts by discussing the teaching in senior high school based on the theory of cognitive load. On the basis of investigation and research, combined with characteristics of teaching concepts in science education, the corresponding teaching strategies are put forward and the teaching design is carried out.
The methodology and methods used in this thesis are based on the study of Meissner (2012), as further explained in this chapter. The essential approach adopted was as follows:
- Select typical teaching cases for analysis and application in teaching practice.
- Teach using the experimental approach and employ a pre-test and post-test approach. For the pre-test, in order to ensure the validity of the experimental implementation, the performance of the students in the experimental class and the control class was tested, to determine whether there were significant differences between the two classes. During the experimental period, the teacher asked the students to fill in a cognitive load self-assessment scale after class and complete the corresponding after-class test questions. The students’ psychological stress levels were also tested and an evaluation of the material’s difficulty in both the experimental class and the control class was undertaken, and this was compared with the results of the corresponding after-class test questions. For the post-test, the biology scores on the students’ final examination (Balschweid, 2002) in both the control class and the experimental class are taken to determine whether there is a significant difference between the students’ post-test scores under two different teaching designs.
- Literature research
According to the research purpose, through extensive reading of the literature, the basic theories of the teaching of scientific concepts and cognitive load theory are examined, and the academic history and research trends of the related disciplines in this thesis are discussed. On the basis of previous chapters, the perspective of this thesis is identified, and the object and content of the study are determined.
- Questionnaire
Based on the theory of cognitive load, teachers and students completed questionnaires to understand the current situation of teaching of concepts in science and the causes of students’ cognitive load in concept learning, and to find out which parts in the process of teaching produce the greatest cognitive load, so as to provide a basis for better implementation of the teaching of concepts in science education. The students were given a self-assessment questionnaire to measure cognitive load. There was also a general questionnaire for both the students and the teachers about science education.
- Case analysis
Making use of partial or complete teaching cases, this thesis explains the main ideas and methods of science concept teaching in the light of cognitive load theory.
- Experimental research
Through collecting and analysing data from a pre-test, mid-test and post-test, the conclusion of the experiment is drawn. Cognitive load analysis is undertaken of scientific experiments on the process of plant cell mitosis.
3.2.2.1. Internal cognitive load analysis
3.2.2.1.1 Complexity and interactivity of mitosis in relation to cognitive load
The process of plant cell mitosis is an important yet difficult part of science education. This chapter includes an explanation of how students learn the process of cell production, development and death under the background of learning the structure, material composition and function of life systems. The abstract process of eukaryotic mitosis is complex. Understanding it requires considerable prior knowledge of cell structure, including that of the nucleus and chromosomes, in particular, the behaviour and number of chromosomes, the role of DNA and the arrangement of genetic material during mitosis. It is difficult for students to understand the process of equal distribution to two daughter cells after replication, particularly given that students’ abstract thinking ability is not mature. In addition, the study of meiosis, the laws of genetics, DNA replication and transmission of genetic information are all based on an understanding of mitosis. That is to say, mitosis is not only the outcome of teaching, but also an important basis for what will be learned later. This knowledge is closely related to what has been learnt before and what will be learnt after. It can be seen that mitosis is a topic with high complexity and interactions with other topics, which will present students with a greater internal cognitive load.
3.2.2.1.2 Learners’ experience and cognitive level
Students will have learned about cell division from junior high school biology textbooks. They know that cells produce new cells through division, but this is only a preliminary understanding of cell division. In respect of the specific process of cell division, there will have been no in-depth study, such as cell structure in the process of cell division. What happens? How will the number and shape of chromosomes change? What happens to the amount of DNA in a cell? and so on; the students do not have a thorough understanding of these issues. In addition, students have learned the content of the first five chapters (Biology electronic textbook for senior high school, Human Education Edition, the system in China) (Mladen Mario & Milorad, 2018), which covers the material composition, structure, and function of cellular life systems, and therefore lays a foundation for learning the process of cell mitosis. At the cognitive level, through nearly a semester of high school biology learning, students’ learning ability will have been further improved. The ability to analyze and solve problems independently has begun to be formed, but there is still much room for improvement. In addition, students’ abstract thinking ability and comprehensive thinking ability have further matured, which lays a cognitive foundation for learning difficult topics such as mitosis. However, due to the demanding nature of the content of this topic, which is more abstract and complex than students are used to, given that students’ abstract thinking ability is not yet mature, and students have greater difficulties in understanding.
From the above analysis, it can be seen that the learning content of the process of plant cell mitosis is complex, interactive, and abstract. Learning this part of content requires students to have a rich knowledge base.
3.2.2.1.3 Analysis of external cognitive load and relevant cognitive load
External cognitive load is related to the order and mode of presentation of concepts and the required learning activities. Teachers’ fast and slow speech, clear language expression, teaching rhythm, teaching media, teaching methods and so on can help reduce external cognitive load for students. The content of this topic is theoretical and complex. In the process of mitosis, teachers can present scientific education concepts to students through group activities, wall charts, multimedia animation, and other resources, rationally integrate these resources, and reduce the students’ external cognitive load. Related cognitive load plays an important role in the construction and automation of schemata (Cheon, 2012). Appropriate increases in cognitive demand can improve the effectiveness of learning. In the case of sufficient cognitive resources, the related cognitive load should be increased appropriately, such as designing a lively and engaging classroom introduction, so that students’ attention can be quickly focused on classroom learning, and more cognitive efforts should be devoted to the process of building new concepts. Furthermore, students can be urged to take notes to improve their understanding of conceptual knowledge. In addition, in the process of conceptual teaching, we should also pay attention to the connection with the previous knowledge, and make use of the related schemata in students’ cognitive structures to promote the understanding of concepts.
This thesis explores the implementation of a PBL teaching strategy in science education and examines how the distribution of three kinds of cognitive loads affect the implementation of PBL in K12 Science education by combining quantitative and qualitative research methods, as well as the application of cognitive load theory in a PBL teaching strategy. The specific research questions are:
(1) How does a PBL teaching strategy perform compared to a traditional approach in K12 science education in terms of short-term memory, long-term memory and skill development?
(2) Does the instructional teaching approach (PBL) have any effect on students’ cognitive load?
(3) What is an efficient instructional teaching strategy under the framework of cognitive load theory in K12 science education?
3.3.2.1 Study: Investigation and research on the current situation of the teaching of science concepts in senior high school based on cognitive load theory
3.3.2.1.1 Questionnaire design
In order to understand the cognitive load involved in the teaching of scientific concepts in senior high schools, a questionnaire was designed based on cognitive load theory to investigate the cognitive load of senior high school students in the learning of scientific concepts and the teachers’ cognitive load in the teaching of scientific concepts from the perspectives of students and teachers. Diagnostic analysis is made on the current load, so as to provide a basis for the formulation of conceptual teaching strategies based on cognitive load theory, and make the research more pertinent and applicable. The questionnaire used for this thesis was developed and designed through reading and close examination of the related literature.
The questionnaire was designed on the basis of the Richter scale (Richter, 2006). The specific assignment of grade evaluation is as follows: 4 = fully consistent, 3 = more consistent, 2 = less consistent, 1 = completely inconsistent. The bigger the numerical value, the smaller the load, and the better the learning situation, while the smaller the numerical value, the bigger the load and the worse the learning situation. The data were analysed using the SPSS22.0 software. The software was used to calculate the mean cognitive load measure from the control group versus the experimental group.
- a) Questionnaire for students
Because students have subjective and objective attitudes towards their own learning process and teachers’ teaching process in teaching, they have a relatively accurate understanding of their own learning process and learning results. Therefore, starting from the three dimensions of internal cognitive load, external cognitive load and related cognitive load, and considering the influencing factors of cognitive load, the questionnaire is designed with students’ learning behaviour, teachers’ teaching behaviour and teacher’s evaluation as the starting point to understand students’ conceptual learning and cognitive load status. The dimension design table of the questionnaire is shown in Table 3.1. (Appendix 1 provides details of the specific student questionnaire.)
Table 3.1 Questionnaire dimension design of the current situation of science concept learning for senior high school students
| First level index | Secondly level index | Third level index | Numbers of corresponding questions |
| Internal cognitive load | Characteristics of learners | Cognitive ability | 1 |
| Existing knowledge and experience | 2 | ||
| Nature of learning materials | Content difficulty | 3 | |
| Content quantity | 4, 5 | ||
| Content complexity | 6, 7 | ||
| External cognitive load | Learning time | Teacher speaking speed | 8 |
| Teaching progress and rhythm | 9, 10, 11 | ||
| Content presentation | Teacher talk | 12 | |
| Blackboard writing | 13, 14, 15 | ||
| Teaching media | 16, 17, 18 | ||
| Related cognitive load | Learner-task interaction
|
Learning interest | 21 |
| Emotional arousal level | 22, 23 | ||
| Metacognitive competence | 24, 25, 26, 27 |
- b) Questionnaire for teachers
Teachers’ understanding and application of cognitive load and their perceptions of students’ learning effect in the biology classroom will influence both the teaching effect and students’ learning effect. Under the guidance of cognitive load theory, the teacher questionnaire is made from the viewpoints of internal cognitive load, external cognitive load and related cognitive load, respectively, so as to understand the cognitive load from the teachers’ perspectives. Table 3.2 shows the questionnaire item descriptions. (The full teacher questionnaire is shown in Appendix 2.)
Table 3.2 Questionnaire dimension design of current situation of science concept teaching for senior high school students
| First level index | Secondly level index | Numbers of corresponding questions |
| Internal cognitive load | Psychological capital | 1, 2 |
| Learning efficiency | 3, 4 | |
| Learning materials | 5, 6 | |
| External cognitive load | Teaching methods | 7, 8, 9, 10, 11, 12, 13 |
| Interaction between teachers and students | 14, 15, 16, 17, 18 | |
| Learning materials and presentation methods | 19, 20, 21, 22 | |
| Related cognitive load | Learning motivation | 23, 24 |
| Study hardness | 25, 26 | |
| Strategy and method | 27, 28 |
3.3.2.1.1.2 Research and implementation
This thesis is a case study of a middle school Lushan Gate Fire Squadron in Nanning City, Guangxi Province, China. In October 2018, an experimental was carried out with students from six Grade One classes (aged 14-16 years) from this school and all of the biology teachers. The theory adopted the principle of randomized classing in the selection of both classes of students. The types and learning levels of students in each class were similar. Three hundred questionnaires were sent out and 294 were completed anonymously and returned. Four of them were excluded because they were invalid on the grounds of conflicting selection. 290 valid questionnaires were therefore recovered (a validity rate of 97%). A questionnaire was also completed by the 10 biology teachers in the middle school. Five of them were Grade One teachers with over 10 years of teaching experience, five were Grade Two teachers, two of whom had over five years of teaching experience, and the other three had three to five years of teaching experience. All ten of the issued teachers’ questionnaires were retrieved; no invalid questionnaires were found (a validity rate of 100%).
3.3.2.2 Experiment 2: Apply PBL teaching strategy with various grades and various science topics
With the implementation of basic education reform in many countries, science teaching has undergone changes in both teaching methods and content (Matthews, 1989). In terms of teaching methods, those methods which emphasize knowledge rather than scientific inquiry have sometimes changed into teaching methods that emphasise both knowledge and scientific inquiry. Teaching content reflects the science discipline. The basic ideas and knowledge structure have helped change the knowledge imparting system from ‘what to test’ to ‘what to say’, and, at the same time, it has brought enormous learning pressure to students caused by the rapid increase of knowledge. At the high school stage of training basic education talents, in order to achieve good results in the college entrance examination, many course assignments and expanded information on subject knowledge have crossed the threshold of the students’ lives in high school (Leyba, 2009). Many learning tasks have caused students to study under excessive cognitive load. Therefore, how to reduce the cognitive load of students in scientific learning is discussed in this thesis. To promote the effective teaching of science in senior high school, I try to make theoretical speculation alongside conducting empirical research on the load of science learning from the perspective of cognitive load theory.
3.3.2.2.1 Significance of this experiment
This thesis focuses on the actual needs of basic education and the internal development of cognitive theory. It has research significance for the shortcoming in the extant literature regarding cognitive load associated with high school science learning. To analyse the load of science learning in senior high school and to improve students’ information processing ability, Table 3.3 gives psychological and cognitive factors of common scientific learning difficulties among senior high school students
Table 3.3. Psychological and cognitive factors of common scientific learning difficulties among senior high school students
| Factor | Example |
| Insufficient storage of students’ known knowledge | Difficulties in writing basic terms of science |
| Low degree of knowledge structure | Keep in mind that the calculation principal of oxygen reduction reaction is not applicable |
| Incomplete representation of scientific knowledge | Incomplete understanding of the essence of the reaction |
| Poor ability for representation of scientific questions | There is no way to start without inference |
| Disturbance of pre-scientific concepts | The implications of the concept of electrolysis on the concept of ionization |
| Mind-set | Some computational problems will not be solved by conservative thinking |
| Low metacognitive ability | It is easy not to pay attention in class when undertaking homework |
It is an indisputable fact that the task of high school learning is heavy. Many subjects, internal difficulties and abstract concepts make it difficult for many high school students to adapt to the high school learning environment. School teaching consists of many courses. In class, students should listen to teachers, and after class, time should be spent digesting and completing homework. Science is now considered an important school subject. Many students appear to understand what the teacher says in science class but, after class, they cannot successfully complete problems independently. There is a situation of students experiencing difficulties with their learning (Herceg, 2017). Difficulties in science learning lead to inefficient learning. Therefore, the causes of high school science learning load need to be analysed. The purpose of this thesis is to improve students’ ability to digest and process new knowledge and information.
To increase the depth of cognitive load research and promote the application of CLT in scientific disciplines, most of the previous empirical studies were based on qualitative research in non-practical teaching laboratory scenarios. The present study extends this to actual teaching, because research on real teaching helps to enhance the theory’s ability to guide practical activities. Existing published research started with the study of simple learning materials and the study of single learning materials. It has developed to the study of specific courses which are consistent with the content of school teaching. According to the results of literature research, there are few studies on the combination of cognitive load theory and the teaching of scientific disciplines. Therefore, this thesis attempts to conduct research on the combination of cognitive load theory and scientific disciplines, so as to promote the depth and breadth of research into cognitive load theory in scientific disciplines.
To measure the distribution of cognitive load in science learning in senior high school, and provide a reference for effective teaching in senior high school, cognitive load measurement has become an important part of the theoretical system of cognitive load. Some studies have undertaken basic research on the design of cognitive load scales, employing tests of reliability and validity. Based on this, this thesis uses a cognitive load questionnaire with scientific characteristics, three dimensions and 20 items to study science in high school. After the first measurement of load, the basic characteristics of load distribution can be analysed by quantifying each dimension, which provides a theoretical basis for the implementation of effective teaching in senior high schools.
3.3.2.2.2 Research objects
In order to understand the cognitive load of senior high school students in the process of learning science, two classes of senior high school students in Lushan Gate Fire Squadron, Guangxi Province at different levels in Grade One and Grade Two in the study completed a questionnaire on the scientific cognitive load of senior high school students (see Appendix 1 for details). The questionnaires were analysed, focusing on three aspects in the study. The subjects surveyed for scientific knowledge were senior military examinees. The specific respondents are listed in Table 3.4.
3.3.2.2.3 Selection of questionnaire items and interview items
- Selection of questionnaire items
In order to make the sample representative, the studied classes include both intervention classes and control classes. To enhance validity of the results, the questionnaires were tested in two groups – A and B – at the school. The distribution of classes is shown in Table 3.4.
Table 3.4 Sample information
| Test type | Class | Class size | Number of boys | Number of girls | Age of the students |
| Pre-test | Class 11, Grade 1, Group A | 57 | 29 | 28 | 14-15 |
| Class 17, Grade 1, Group A | 45 | 24 | 21 | 14-15 | |
| Test | Class 12, Grade 1, Group A | 46 | 23 | 23 | 14-15 |
| Class 15, Grade 1, Group A | 43 | 21 | 22 | 14-15 | |
| Class 19, Grade 1, Group A | 54 | 28 | 26 | 14-15 | |
| Class 23, Grade 1, Group A | 45 | 27 | 18 | 14-15 | |
| Class 13, Grade 2, Group A | 41 | 21 | 20 | 15-16 | |
| Class 16, Grade 2, Group A | 47 | 27 | 20 | 15-16 | |
| Class 13, Grade 2, Group A | 52 | 34 | 18 | 15-16 | |
| Class 15, Grade 1, Group B | 52 | 24 | 28 | 14-15 | |
| Class 16, Grade 1, Group B | 52 | 23 | 28 | 14-15 | |
| Class 5, Grade 2, Group B | 50 | 32 | 18 | 15-16 | |
| Class 6, Grade 2, Group B | 47 | 27 | 20 | 15-16 | |
| Class 7, Grade 2, Group B | 54 | 30 | 24 | 15-16 |
The intervention classes in group A are Class 19 (Grade 1), Class 23 (Grade 1) and Class 16 (Grade 2). In group B, the intervention classes are Class 16 (Grade 1) and Class 7 (Grade 2). The rest of the classes are control classes.
In order to investigate the reliability and validity of the questionnaire, 102 questionnaires were distributed in a pilot, and 100 valid questionnaires were collected. For the main study, a total of 635 questionnaires were sent out, 583 valid questionnaires and 52 invalid questionnaires were recovered, that is, the questions were answered correctly and honestly without any interviewer’s influence. The invalid questionnaires had answers that were either not answered or had responses that did not answer the questions or diverged from the main idea. The recovery rate was 92%, which met the basic requirements of the questionnaire recovery rate.
- Selection of interviewees
The interviewees were 25 senior high school graduates of Lushan Gate Fire Squadron. The interview schedule consisted of representative questions selected from their usual daily training exercises and using test questions, and targeted questions on the process of solving the questions. The results of the interview are discussed later in chapter 4.
- Development of questionnaire
School students come into contact with science learning after the Grade 3 examination. The first year of science learning in junior middle school mainly provides students with the basis for further studies of science. After entering senior high school, there is a substantial increase in the amount of science they are taught. Senior high school science has the following characteristics compared with junior high school science:
The concepts in senior high school sciences are more abstract and theory plays a greater role. Entering Grade 1 of senior high school, students are exposed to many abstract concepts, such as the amount of a substance, gas molar volume, oxidation-reduction reactions, ionic reactions, etc. These are difficult concepts for those new to senior high school to understand. Balancing chemical equations and principles of electrical science in Grade 2 of senior high school are theoretical and difficult to use, which results in students having a high level of cognitive load.
Acceleration of progress and teaching content. There are two compulsory and six optional science textbooks in senior high school. According to the general requirements, both compulsory and at least two optional textbooks should be studied. Their contents require that they must be completed in the first and second year of senior high school. The first grade of science class is generally three classes per week, and for Grade 2 of senior high school there are generally four classes per week. Due to the limited time available to impart and explore, the teaching progress is required to be fast. The teaching content includes basic concepts of science, knowledge of elements and compounds, knowledge of organic compounds, scientific experiments and so on. The content will bring learning pressure to students in both breadth and depth.
More advanced examples. In junior high school science, elements and simple compounds are studied. In high school science, elements and compounds consisting of a metal (e.g. sodium, aluminium, iron, copper) and non-metal (e.g., nitrogen, oxygen) are the focus; there is a detailed introduction to elements and their important compounds – through the analysis of the atomic structure of homologous elements – and students study properties of similarity and progressive change, using induction and comparison. The scientific research methods of reasoning and prediction are more advanced compared to those of junior high school.
Evidently, there are clear differences between senior high school science and junior high school science. It is therefore necessary to explore the cognitive load of students caused to both groups in the process of learning science. If senior high school teachers know the source and influencing factors of students’ load as early as possible, they can timely choose appropriate teaching strategies based on learning content to alleviate students’ problems.
The questionnaire method focuses on the purpose of the research topic, designing a series of questions related to the topic, and then getting the answers to the questions by the respondents completing the questionnaire. Finally, by using SPSS and/or other software for statistical analysis, the related information is obtained. The questionnaire is the principal method used in this study, supplemented by interviews. Questionnaires collect data by means of a survey. It is an empirical method with a certain internal relationship between sampling, the questions asked and the statistical analysis. A questionnaire is a method for researchers to obtain relevant information and materials by designing precise questions in advance. The researcher provides a series of questions related to the purpose of the research in written form, and asks the respondents to answer them. Through collecting, sorting and analysing the answers, the researcher obtains the relevant information by applying a theoretical framework to analyse the data. The questionnaire method is especially suitable when researching a large number of people, so the research can be carried out quickly and efficiently as many people can be surveyed in a short time. A questionnaire can be used for quantitative analysis of the survey results, and is especially suitable for the research of this thesis.
3.3.2.2.4 Principles of questionnaire development
Questionnaire compilation should follow the basic principles of questionnaire design in general social science research.
- Principle of objectivity. The principle of objectivity requires faithfully reflecting the cognitive load in high school students in learning science, so the design of the questionnaire should combine the characteristics of high school science, the characteristics of students and the current arrangement of science class hours.
- Necessity principle. The influencing factors of high school students’ cognitive load in learning science are multi-level, so factors should be selected according to the size of the influencing factors and previous research.
- Possibility principle. The object of the cognitive load questionnaire is senior high school students, so the questionnaire design should take into account the expected answers that students may make. The design of the questionnaire should conform to respondents’ psychological characteristics, and their ability to understand and solve problems, so that they can quickly answer questions when faced with the questionnaire.
- Voluntary principle. The fact that the respondents volunteered to answer the questionnaire is the key to understanding the scientific cognitive load. Therefore, in the design of the questionnaire, anonymous methods are used to eliminate students’ worries, so that the respondents can express their true cognitive load situation, and lay the foundation for the authenticity of the follow-up questionnaire conclusions.
3.3.2.2.1.5 Questionnaire preparation method
In the process of compiling and designing the Questionnaire of Scientific Cognitive Load for Senior High School Students, this thesis adopts the methods of literature research and direct experience to design the questionnaire from the aspects of question angle, question design and investigation purpose. Firstly, this thesis consults the existing literature related to the questions of Cognitive Load for Psychological Subjects and according to the reference opinions of the instructor and the experts of science. Secondly, combining with my own understanding of the cognitive load factors in the process of science teaching in senior high school, I designed a cognitive load questionnaire with the characteristics of science disciplines.
- The conception of compiling scientific cognitive load questionnaire in Senior High School
Based on the background of the discipline of cognitive load theory and the research of related literature, the concept of cognitive load is compiled according to the characteristics of science disciplines. The questionnaire of high school scientific cognitive load consists of three dimensions: internal cognitive load items, external cognitive load items and related cognitive load items.
- Learners’ internal learning characteristics and emotional experience
External cognitive load mainly tests high school science knowledge factors and teacher factors; related cognitive load mainly tests the implementation of effective learning styles of learners. A 5-point Likert scale was used: the highest score for each item was at point five and the lowest was at point one. The total for the questionnaire was obtained by summing the scores for all the items. The higher the total, the greater the cognitive load while learning science; the lower the total, the smaller the cognitive load.
3.Acquisition of related items
The item acquisition of the cognitive load questionnaire used in the study is mainly based on the existing literature (Chapter 2) and the characteristics of scientific disciplines. The internal load component is set as 18 items with three factors, the external load component is set as 20 items with three factors, and the related load component is set as 12 items with two factors.
4.Questionnaire analysis and processing
The results of the questionnaire were analysed using SPSS software, and the reliability and validity of the questionnaire were ascertained through comparison with the control group. At the same time, the three dimensions of cognitive load and their relationship to total load are analysed by multiple factors. The validity and reliability analysis of the questionnaire comes from the data of two classes in the pre-test. For some items of the questionnaire, KMO value and Bartlett’s test of sphericity are used. The larger the specific value of KMO, the more common points between items, the more suitable the questionnaire is for cognitive load measurement research. On the other hand, KMO is more suitable for cognitive load measurement research. When the value is < 0.5, it is not appropriate to make a specific analysis of the related factors.
If Bartlett’s test of sphericity value reaches a significant level, it shows that there are common factors among the related matrices of the designed questionnaire items, which are suitable for the analysis of related factors. If it does not reach a significant level, the design problem is inappropriate. After analysis, the KMO value of the questionnaire was 0.855 (p < 0.001), which indicates that the questionnaire data are valid and can be used for further analysis. The reliability analysis of the questionnaire is also based on the questionnaire data of two classes in the prediction test. The standardized alpha coefficient = 0.959 is calculated by reliability analysis for 50 items in this volume. According to the research of general psychology, it is considered that the questionnaire has good reliability if the standardized alpha test exceeds 0.7. Each item and option has good reliability and is suitable for the subsequent research.
The investigation and measurement of cognitive load is a systematic project. Therefore, the theoretical framework and cognitive load measurement are studied in detail from the perspective of theoretical speculation. Furthermore, the factors affecting cognitive load of scientific learning are analysed in depth from the perspective of empirical research and combined with specific scientific knowledge.
3.3.2.2.6 Analysing the causes of the load and the corresponding teaching strategies
Part One: Theoretical speculation
Origin of the Problem Research Objectives is listed as follows.
- The concept, classification and characteristics of cognitive load theory
- The measurement basis of cognitive load
- Three dimensions and overall load distribution of scientific cognitive load in senior high schools
- Characteristics of scientific factual knowledge in senior high schools
- Characteristics of scientific theoretical knowledge in senior high schools
- Characteristics of scientific skilled knowledge in senior high schools
Part Two: Empirical study
- Distribution of three kinds of load and total load of scientific cognitive load in senior high school (based on questionnaire)
- Teaching strategies and design of scientific factual knowledge in senior high schools (factual question interview)
- Teaching strategies and design of scientific and theoretical knowledge in senior high schools (interview with theoretical questions)
- Teaching strategies and design of scientific skilled knowledge in senior high schools (skilled question interview)
Research factors
- The influence of school factors on the three types of cognitive load distribution
- The influence of students’ gender on the three types of cognitive load distribution
- The influence of class level on the three types of cognitive load distribution
3.2.2.3 Experiment 3: Teaching process of the topic that is being studied
The specifics are detailed in Table 3.5, which provides a list of the teaching processes for ‘the process of plant cell mitosis’.
Table 3.5 List of teaching processes for ‘the process of mitosis of plant cells’
| Teaching links | Teaching content | Teacher activities | Student activities | Control intention of load |
| Perception concept | Creating problem situations and introducing concepts – cell division | PowerPoint shows pictures of injuries and wound healing, which raises questions for students to think about: 1. How does the process from injury to wound healing work? 2. In this process, new cells are produced in organisms. How do they produce new cells? In this lesson, we will learn the main points of eukaryotic cells. The mode of division is mitosis. | Recall what you have learned and answer: cell division | Introducing the familiar experience from ‘injury’ to ‘wound healing’, that is, combining with students’ cognitive structure, raising questions from familiar things, increasing students’ cognitive load, activating related schemata in LTM, promoting the processing of new knowledge and information, and stimulating students’ learning at the same time. Interest in learning enables students to invest more cognitive efforts in schema construction, so as to improve their learning quality. |
| Show learning goals in the form of questions | Play the whole process of plant cell mitosis animation; let students have a general impression of mitosis. Then the learning objectives are presented in the form of questions: What are the changes in the shape and number of chromosomes at different stages of cell division? | Watch PowerPoint | Make the students clear about the learning content and key points of this lesson. It will help the students to consciously and adequately process the cognitive load, increase the related cognitive load, and avoid distracting their attention from the related information, so as to reduce the external cognitive load and effectively control the cognitive load. | |
| Arousing and resolving cognitive conflicts and constructing scientific concepts | Inquiry question 1: What changes have taken place in the cell division interval?
Construction concept: cell division interval |
1. PowerPoint shows the mitotic cell cycle diagram and asks questions such as Why does the mitotic interval take up much longer than the mitotic phase in a cell cycle? Then, through layers of questions, students are guided to focus their questions on chromosomes.
2. Play videos of cell division intervals to show the changes of interphase cells. 3. Teacher’s supplementary activity: Explain the relationship between chromosome and chromatin through chromosome model, introduce the results of chromosome, chromatin, centromere, chromosome duplication, and the concept of chromatid, summarise the characteristics of mitotic interval: prepare for the mitotic phase, complete the replication of DNA molecule and synthesis of related proteins. |
Group discussion: After cell division, the genetic material in the nucleus and its nucleus is also divided into two parts, and the genetic material is divided into chromosomes. Referring to the textbooks, it is concluded that interphase is the completion of chromosome duplication. | The change of splitting interval belongs to content, which is more abstract, and will bring higher external cognitive load to students. This process is presented in the form of a video explanation, which visualises the abstract content and reduces the external cognitive load. At the same time, the explanatory video utilises both the learner’s visual and auditory channels, improves the efficiency of WM, makes rational use of the channel effect of cognitive load, and improves the learning effect. From the outside, through the way of questioning, we can reveal and implement the relationship between the knowledge from the change of nucleus to chromosome to the change of DNA layer by layer, so that we can integrate the knowledge and information we have learned into the existing schema, increase the related cognitive load and promote the effective processing of the knowledge we have learned. |
| Question 2: How are chromosomes evenly distributed into two daughter cells after replication? Constructing concepts: cell division prophase, metaphase, anaphase and cell division. | 1. Teachers ask questions:
(1) What changes have taken place in the shape and number of chromosomes at different stages of cell division? What changes have taken place in the amount of DNA? 2) How did the spindle form? When did it form? When did it disappear? 3) When did the nucleolus disappear? 4) Play videos of prophase, metaphase, anaphase and cell division. After watching the videos, we used cardboard models to display chromosomes in different stages to simulate the process of cell division. Summarise the characteristics of each phase. Teacher’s supplementary activity: Summarise what you have remembered of the characteristics of each phase. |
Watching the video with questions, the group members discuss with each other and complete the learning task: the behaviour of putting chromosomes in different phases with cardboard, and summarise the characteristics of each phase. Each group selected the team leader to show the model made by this group and explain the characteristics of this phase. | In the form of learning tasks, learning materials are divided into several learning segments, and appropriate time is set aside between each successive two segments so that students can select information content from each segment and make full cognitive processing, which reduces the internal cognitive load.
The knowledge of cell division process is at too small a scale, especially the change of chromosome behaviour. This procedure uses the example answer effect of cognitive load theory to show the procedure of solving problems to students by playing explanatory videos. It reduces the WM load and enables students to better complete their learning tasks. |
|
| Summarise the process of mitosis, leading to the significance of mitosis | 1. To summarise the changes of chromosomes, chromatids and DNA amount during mitosis by means of a table. The complete process of mitosis is presented to the students at one time with pictures of different stages of mitosis at the top of the table, so that the process of mitosis can be returned from part to whole.
2. Guiding students to sum up the characteristics of mitosis in terms of the number of replications, the number of occurrences of splitting and the results of splitting, and then to draw out the significance of mitosis. |
1. Complete the table.
2. Summarise the significance of mitosis. |
By properly integrating and displaying the pictures and related text information of each mitotic phase, students’ attention is interrupted and the effect of attention separation is eliminated, which is conducive to students’ learning of knowledge. In addition, the design of this teaching link also follows the principle of skilful use of graphics in the principle of multimedia courseware making, that is, the presentation of words and pictures is integrated, and students are more able to master it. | |
| Consolidation of concepts | Consolidate the concept of ‘mitosis’ | Teachers show examples of mitosis:
The following account of plant cell mitosis is incorrect. A. Intermittently completes DNA replication and synthesis of related proteins. B. Each chromosome at prophase contains two sister chromatids and two sister chromatids. C. The centromeres of metaphase chromosomes are arranged on the equatorial plate, with fixed morphology and clear number. D. The number of chromosomes doubled at anaphase and a cell plate appears at the end of the equatorial plate. |
Students review the process of conceptual construction, distinguish the characteristics of mitotic stages in the options, and choose the correct answer. Students have a deeper understanding of the mitotic process. | After learning the concept of mitosis, a case study is used to give corresponding examples to consolidate the concept of new learning and to promote students to form correct schemata in their brains. |
This teaching case controls the cognitive load in the teaching process from three aspects: reducing the external cognitive load, reducing the internal cognitive load, and increasing the related cognitive load. In the introductory part, it mainly combines the students’ own knowledge and experience to improve their interest in learning, increase the related cognitive load, and make them invest more cognitive efforts in learning. Showing the teaching objectives to the students can help them clarify their learning objectives, which can avoid the waste of cognitive resources on unrelated information and reduce the external cognitive load. In the process of teaching the new course, the material presentation method of video explanation is mainly used to reduce the external cognitive load, and the method of dividing learning materials is mainly used to reduce the internal cognitive load. By reviewing the knowledge, we have learned and linking it closely with the process of mitosis, we can increase the related recognition. Under the guidance of cognitive load theory, the classroom summary uses the method of combining pictures and texts to properly integrate and display pictures, and related text information about the different stages of mitosis, thus avoiding the distraction of students’ attention, eliminating the effect of attention separation and reducing the external cognitive load. Finally, the author uses the example answer effect of cognitive load theory to help students consolidate their conceptual knowledge.
3.3.2.3 Conceptual teaching strategies based on cognitive load theory
3.3.2.3.1 Combining students’ cognitive structure, creating problem situations and increasing related cognitive load appropriately
In the process of conceptual learning, teachers cannot directly give definitions of concepts to students and explain concepts by other concepts. Instead, they should relate scientific concepts to students’ daily lives, raise problems related to conceptual knowledge learned from life phenomena, create corresponding problem situations, and motivate students to think by considering problems. Students’ cognitive motivation enables the related schemata in their LTM to be invoked and participate in the processing of conceptual knowledge, reducing the load of WM, thus minimizing the internal cognitive load, increasing the related cognitive load and completing the cognitive task smoothly, so as to realise the construction of the meaning of the concept.
In the teaching of the concept of ‘mitosis of eukaryotic cells’, teachers can create problem situations based on students’ prior knowledge and their life experiences, so as to drive students’ cognitive motivation using problems. Injuries are familiar things that every student has experienced and the wound will heal after the injury; then we can combine this life experience of students and put forward the following questions about mitosis:
- After we are injured, the wound will heal soon. How does the wound heal?
- Is there any difference between the newly generated cells and the original cells?
- How do the genetic characteristics of cells remain stable during division?
- How are the cells divided evenly during division into two daughter cells after genetic material replication?
In this way, these questions can be used to stimulate students’ interest in learning, so that they actively participate in learning about mitosis.
3.3.2.3.2 Constructing the overall context and framework of concepts and dividing learning tasks to reduce internal cognitive load
The internal cognitive load is determined by the nature and characteristics of knowledge itself. For the teaching of complex concepts, the author needs to sort out the key points of knowledge, and construct the necessary overall context and framework of core concepts, so as to control the internal cognitive load and promote students’ in-depth understanding of the knowledge they have learned.
The concept of ‘plant cell mitosis’ is abstract and complex, and it contains many lower-level concepts. It therefore brings a high level of cognitive load to the students’ learning. In order to reduce the internal cognitive load, the teacher should establish the overall context and framework of this concept, clarify the learning objectives of each lesson, highlight the difficulties in teaching, eliminate ‘redundancy’, avoid excessive learning content and reduce the internal cognitive load. In addition, for the study of the process of mitosis, this part of knowledge is divided into several learning tasks in the form of questions, that is, the material is divided into several segments, and appropriate time is set aside between two consecutive segments for students to think, so that they can choose the information content from each segment for further study.
3.3.2.3.3 Integrating teaching resources and optimizing conceptual presentation to reduce external cognitive load
The content of ‘plant cell mitosis’ is complex. If only presented to students in the form of plain text, it will cause a higher external cognitive load to students’ learning and interfere with students’ processing of knowledge and information. Therefore, this part of the content can use multimedia or wall charts to present the learning content to students. When using this method, teachers should integrate pictures or animations, words and sounds on the basis of the channel effect of cognitive load theory and the separation effect of attention, so as to make students’ visual channel and listening easier. The awareness channel is fully utilized, while avoiding the distraction of students’ attention and the aggravation of WM load. For example, when using video or animation to teach ‘plant cell mitosis’, teachers should be good at using students’ visual and auditory dual sensory channels to explain video animation dubbing while removing text presentation in video or animation, so as to simplify teaching, eliminate redundant information and avoid students being distracted. When teachers use wall charts to teach, it is best to integrate the related text information into the picture, so that the pictorial information is consistent in time and space, to ensure that students receive information continuously and smoothly.
3.3.2.3.3.1 Content analysis
Plant mitosis is an important and difficult topic in the compulsory science course, even at high school level. According to the arrangement of the textbook, we can see that the content of this section is a link between the preceding and the following sections. Before learning the content of this section, students have learned the material, structure and function of the life cycle. This section in the textbook presents important content in the process of the birth, development and death of the life system. In the following sections, students will learn about cell division in the context of division, giving rise to the sexual cells. Meiosis, the hereditary law of organisms, cloning, cell totipotency, and tissue culture are closely related to the characteristics and significance of mitosis, especially the study of meiosis and hereditary law, because the study of meiosis should be based on prior knowledge of mitosis. It can be seen that plant cell mitosis occupies an important position in high school science. It is not only a continuation of the preceding study, but also the foundation for the succeeding study.
3.3.2.3.3.2 Three-dimensional objective
The main objectives of the teaching are:
- Knowledge objective: to summarise the process and characteristics of plant cell mitosis.
- Ability objectives:
2a. To train students to analyse and interpret images and engage in abstract thinking through learning the process of mitosis.
2b. To cultivate students’ in their ability to construct knowledge independently.
- Emotional attitudes and values: by constructing the concept of plant cell mitosis, we can identify that mitosis is a dynamic and continuous process, and form a biological thought that integrates part with whole and structure with function.
3.3.2.3.3.3 Important and difficult points in teaching
- Teaching emphasis
The process and characteristics of plant cell mitosis.
- Difficulties in teaching
The changes of chromosome behaviour and number at different stages of plant cell mitosis, as well as the changes in the amount of DNA.
- Analysis of learning situation
High school students have initially formed the ability to analyse and solve problems independently, and have the inherent foundation of learning abstract and complex knowledge. However, because of the thinking characteristics of high school students, they are still in the transition period from concrete thinking to abstract thinking. Therefore, teachers should use appropriate teaching aids to present a visualisation of the teaching content so that students can understand it. At the same time, teachers should try to cultivate and improve students’ abstract thinking ability.
- Teaching and learning methods
The following are teaching methods that teachers use:
- Visual teaching method: Using multimedia courseware to demonstrate the characteristics of the different stages of mitosis in textbooks.
- Comparative teaching method: The number of chromosomes, chromatids and changes in the amount of DNA during mitosis are analysed and summarized by tables or graphs.
- Explanation: Combining the characteristics of mitosis in different stages with the intuitive method, we can solve these kinds of knowledge problems by eliciting and introducing the key points.
In these lessons, multimedia technology plays an important role. It can show the continuous dynamic process of mitosis (that textbooks cannot show) to students through video or animation, so that abstract content can be visualized. It does not only improve students’ abstract thinking ability, but also allows students to construct their knowledge independently. The ability to cultivate knowledge can be achieved through the following methods: 1. Inquiry learning method: Students are guided by the problems created by teachers, exploring and solving problems one by one, and gradually constructing the concept of mitosis. 2. Self-regulated learning: Observe and search related knowledge and information under the guidance of teachers. 3. Cooperative learning method: Under the guidance of the teacher, cooperative learning is carried out in groups and questions to be explored are asked. The questions are discussed, analysed and summarised.
The next chapter, Chapter 4, will discuss the results and outcomes obtained from the methods described in Chapter 3.
Cognitive load theory focuses on information processing in learning (Alasraj, 2013). It can be summarized as follows: WM is the main place of information processing; its capacity is limited. LTM is the place of information storage; its capacity can be regarded as infinite. If the information processed in WM exceeds its capacity, the processing of information will become invalid, which is called cognitive overload. The construction and automation of schemata can reduce the amount of information processed in WM and release more space in WM for processing information (Osamu, 2012). It can be seen that cognitive load theory pays attention to cognitive processing in the learning of students, and its application and concept teaching can optimize the cognitive load in learning from the perspective of students’ cognitive structure, which is conducive to the concept assimilation and adaptation of students and can help students to establish scientific concepts, and should improve learning efficiency (Kilimnik, 2012). Therefore, this study applies cognitive load theory to the teaching and learning of concepts. On the basis of previous studies, it explores the teaching path of biological concepts based on cognitive load theory, in order to improve the quality of biological teaching, and provide some valuable guides for biological teaching instructional design (Jimmie, 2015).
Part of the uniqueness of biology lies in that it is necessary to fully consider the understanding of life from four levels: macroscopic (biological structure visible to the naked eye), microscopic (cell or subcellular level structure visible only under light microscope or electron microscope), sub-microscopic (DNA molecular level) and symbolic (such as the mechanism of explaining phenomena provided by symbols, formulas, metabolic pathways, genotypes, etc.). Based on the highly abstract and hierarchical nature of biological concepts, to a certain extent, it is clear that the external representation forms of biological concepts are rich and diverse. Various representations such as speech, text, schema, symbol, object, model, experiment, demonstration and so on can be used to characterize the concept information from multiple angles. From the perspective of the sensory channels represented by biological concepts, these are diverse, including vision, hearing, and touch. According to the abstract level of the learning object, there are two extremes of narrative representation: concrete verbal representation and abstract symbolic representation. There are many related hierarchical narrative representations in the continuum between these two representations. For descriptive representation, the number of biological variants, such as simulation, modelling, schemata and images, is also considerable.
It is the abstract, hierarchical, pluralistic and other characteristics of high school biology concepts that mean that its external representation should be rich and diverse. However, for most of the abstract concepts (such as gene transcription, DNA replication, enzyme action, etc.) at the sub-microscopic level, the information contained within a single representation can only reflect part of the information of the represented object. If we want more fully to reflect the learning object of biological concept and enable students to really master a new concept, it is very difficult to be satisfied with a single representation.
Biological concepts are formed on the basis of a large number of observations of life phenomena. The study of biological concepts needs to be based on the observation of the phenomena of life, so that students can understand that biological concepts originate from life and serve life. When students learn new concepts, their minds are not a blank sheet of paper. They have encoded and stored corresponding knowledge in LTM. The construction of new concepts is actually a process of selecting and organizing information under the stimulation of new situations, searching and extracting relevant information in LTM under the guidance of teaching activities and constantly transforming, translating and integrating the representation of new construction. Therefore, students should be left to start from their own knowledge and experience, and should be guided on how to construct the general concept of biology by connecting life experience and practical problems, so as to fit the students’ “zone of proximal development” (Bruce, 2012).
As mentioned above, the multi-representation of biological concepts refers to the representation of the same concept learning object by two different forms of representation: verbal representation (narrative representation) and visualization (descriptive representation). Verbal representation not only refers to oral language (pronunciation, intonation, hint, guidance, etc.), but also includes written language (text material, written content) and symbolic language (such as when a dominant allele is expressed in capital letters, and the corresponding subordinate allele in lowercase letter). Visual representation is more diversified, and there is no agreed international classification of visual representations. The common and best way is to divide visual representation into schemata representation.
Specifically, based on the characteristics of biology, multimedia representation generally refers to the use of experiments, physical objects, models, multimedia (images, animation, video, etc.) and other intuitive means to make the teaching content more vivid and specifically integrated within the WM, so as to reduce the internal and external cognitive load of students and increase the effective load. Schemata representation entails extracting the essence of information and presenting it in the form of graphs, which can show the structure of concepts concisely and intuitively, and help students process and summarize concepts more effectively and conveniently. In biology, commonly used schemata are concept maps, schematic diagrams, tables, various other sorts of diagrams, and so on.
Since verbal representation and visual representation have the functions of complementing, limiting interpretation and constructing deep understanding, the multiple external representations of teachers’ optimized combination can promote learners to internalize the multiple representation information of knowledge and integrate this into a meaningful cognitive structure, so as to realize the understanding of the essence of biological concepts. Through multiple representation learning, students can learn the strategies and methods of self-construction of multiple representations, so as to apply them to the learning of new concepts in the future.
All in all, the formation of biological concepts is a process of constantly abandoning non-essential attributes and exploring the essential attributes. Based on its own abstraction, we need to proceed from the actual production, living situation, the knowledge, and experience of learners, and combine the information organized by the above multiple representation methods for cognitive processing, so as to realize the real grasp of biological concepts and guide life and production practice.
In addition, this thesis attempts to apply PBL teaching to the teaching of natural science concepts, and to do so effectively. In the process of natural science teaching class, experimental and control groups are studied in natural science teaching settings. In the process of the experiment, students in the experimental group were evaluated throughout the whole process. After the experiment, a comparison of the test results between the experimental group and the control group was made. A questionnaire on PBL teaching assessed the attitudes of the experimental group, and interviews with some students in the experimental group were conducted to study the effects of the PBL teaching in more depth from the students’ perspectives. In order to promote the reform of science teaching and improve its efficiency, the comprehensive learning ability evaluation of students in this thesis provides a reference for the teaching practice of science teachers.
4.2 Survey results and analysis of biological concept teaching based on cognitive load theory
Concepts are the reflections of the essential attributes of things within the human brain. Concepts are forms of thinking. Connotation and extension are two elements of the concept. The reflection of the special attributes of things is the connotation of the concept, and the sum of the objects with these special attributes is the extension of the concept (Douglas, 2004). If students want to understand and master the concept deeply in order to understand the laws of life and explain the phenomenon of life, then they must have a deep understanding of the connotation and extension of the concept, which is the essence of concept teaching. In the learning process, many students cannot distinguish the true meaning of concepts, definitions and noun terms, and they think that these words express the same meaning. In fact, concepts, definitions and noun terms are different. The expression of definition is often very positive. In expression of the concept, the noun term is the symbol to mark the concept. To understand a noun term does not mean to really understand the concept (Udo, 1989). For example, understanding what is meant by ‘peptide bond’ does not imply an understanding of the process of protein formation.
Concepts are the thoughts and basic forms of the external environment perceived by the students. After learning the concept, students should be able to differentiate the essential characteristics of things, and be able to classify different things according to certain standards. Therefore, high school biological concept teaching refers to teachers taking certain teaching methods and strategies or teaching modes to carry out their teaching according to the related education and teaching theories and certain teaching laws, so as to help students acquire concepts, understand concepts, and be able to apply the concepts. Biological concept teaching is the main content of biology teaching in high school (John, 2015). It mainly includes the following:
- Perception concept: on the basis of existing knowledge and experience of students, perceptual knowledge is obtained from intuitive materials.
- Construct concept: provide representative biological facts, and build concept through analysis, induction and reasoning, to raise perceptual knowledge to rational knowledge.
- Consolidate concept: direct students to review the concept building process and deepen their understanding by asking them to solve related problems.
- Generalisation concept: refine and summarize, form a concept system, and generalize knowledge from special to general.
- Application concept: students can apply related biological knowledge in real life, letting biological knowledge direct their life and learning.
Cognitive theory holds that the cognitive process is universal, each different cognitive stage is unique, and cognitive development is continuous. An important aspect of this theory is the schema, which is the functional unit of cognition. The relationship between subject and object is established through cognition (Locke, 1987). Schemata develop and change with age and experience, which is accompanied by the assimilation, adaptation and balancing of cognitive structures. When someone encounters new things or solves new problems, he/she will introduce new items into the original schema; new knowledge is assimilated into the old knowledge system, so that the cognitive structure will be temporarily balanced (Dwyer, 2010). However, if someone only assimilates the new things into the original schema, but cannot use the existing knowledge to explain the change, then the balance is likely to be destabilized. Then, if the subject can change the original schema to adapt to new things, that is to say, to solve the problem through adaptation, a new balance can also be achieved. The process of individual learning is the development and change of cognitive structure from balance to imbalance to new balance through assimilation and adaptation (Lakonpol, 2015).
Based on the theory of cognitive development, in the teaching of concepts (Derrick, 1993), teachers should take students as the main body, understand the pre-concept knowledge in the minds of students, design reasonable teaching situations, arouse their cognitive conflicts, and adopt appropriate teaching methods to promote the homogenization and adaptation of concept knowledge, so as to establish scientific concepts.
In this thesis, SPSS22.0 software was used to make descriptive statistical analysis of the results of the questionnaire, mainly from the centralized trend and discrete trend of data to confirm the cognitive load of both students and teachers.
4.2.1 Questionnaire results analysis of students
4.2.1.1 Descriptive statistical analysis
The data were collected from 290 valid student questionnaires from both the experimental group and the control group. The results are shown in Table 4.1.
Table 4.1 Descriptive statistics of students’ cognitive load
| N | Mean | Std. Deviation | |
| Internal cognitive load | 290 | 2.65 | .45 |
| External cognitive load | 290 | 2.88 | .39 |
| Related cognitive load | 290 | 2.95 | .45 |
From Table 4.1, it can be seen that the internal cognitive load score of students is 2.65, the external cognitive load is 2.88, and the related cognitive load is 2.95, all of which are higher than the medium critical value of 2.5 (Ezeamama, 2012). It can be seen that the internal cognitive load of students in concept learning is at a relatively low level than the external and the related cognitive load, which also shows that the teaching strategies and methods adopted by teachers in the class basically conform to the cognitive characteristics of students, so that students are learning. There is no excessive cognitive load in concept learning. However, the levels of the three types of cognitive load are different. On the whole, the external cognitive load and the related cognitive load are relatively high, while the internal cognitive load is relatively low. The specific reasons for the cognitive load being high than the medium critical level are as follows:
- The content of biology learning in senior grade one is increasing, the depth and breadth of content are increasing, and the complexity is increasing (Brown, 2008). However, the growth rate of the existing experience level of students is lower than that of learning content in terms of capacity and difficulty.
- Most teachers have a certain level of teaching ability, teaching methods are used properly, course design is more reasonable, and the thinking ability and cognitive ability of senior high school students have developed, and their logic of thinking has increased. Therefore, students do not have excessively high internal cognitive load in concept learning as compared to external cognitive load.
- With the increase in the capacity and difficulty of biology knowledge in senior high school, students are required to apply more effort in learning, which leads to a decrease in the level of interest of some students in learning biology. In addition, due to the intense class hours allocated for biology, many teaching methods in biology teaching are relatively simple, and do not necessarily meet the requirements in terms of stimulating the desire for knowledge among students. This means that the students do not invest more cognitive effort in concept learning (Gwo, 2013).
Therefore, these three factor causes the cognitive load of students tested in this thesis to be relatively high.
4.2.1.2 Cognitive load analysis with different dimensions
4.2.1.2.1 Internal cognitive load
The internal cognitive load mainly depends on the nature of learning materials and the level of experience of students (Song, 2013). The more complex the learning materials, the more difficult it is to learn, the greater the psychological pressure experienced by students in learning, and the higher the cognitive load. However, if the students already have related schemata in their minds, that is, they have a high level of knowledge and experience, the cognitive load experienced is low. If the learners do not have related knowledge and experience, they will have high cognitive load. Table 4.2 lists the results of statistical analysis of internal cognitive load measurements of the experimental group.
Table 4.2 Statistical analysis of students’ internal cognitive load
As can be seen from the table above, for students themselves, in terms of cognitive ability, the score is 2.24 which means a low cognitive load since it is below the minimum critical value (2.5) (Feng et al., 1986). In terms of existing knowledge and experience, the score is 2.76, which means a high cognitive load. In terms of the nature of learning materials: the score of content difficulty is 2.32, and the cognitive load is low, which indicates that students feel more difficult about the learning materials presented by teachers; the score of content quantity is 2.42, which brings less load to students, which indicates that the learning capacity of students in the class is large; the score of content complexity is 3.19, which shows that the learning content complexity increases the cognition load of students.
The reasons for the observed results are as follows:
- For the students themselves, because they have learned the basic knowledge of biology in the junior middle school, and with the increase of the grade and the amount of knowledge, the level of knowledge and experience of the students has increased correspondingly, so the cognitive load on the level of knowledge and experience is not high.
- For a general middle school, most of the students are active in learning. Learning autonomy is not as strong as they will be in high school, members of the class are not attentive enough, attention is not concentrated enough, thinking ability, observational ability and creativity are not strong enough, so there is a high load in terms of cognitive ability.
- When teachers organize learning materials, they do not analyze the knowledge experience and cognitive ability level of the minds of students, and they often overestimate the ability of students, so that most of the students feel that the learning materials presented by the teachers in the class are difficult.
- Most teachers liked to add too much knowledge in an attempt to get students to learn more knowledge, resulting in too much teaching content in the class, which undoubtedly increased the internal cognitive load of the students.
- In the high school biology compulsory 1 ‘molecules and cells’the content of knowledge is not difficult and the interaction between knowledge units is not high, so that when students learn these knowledge units, the amount of information that needs to be processed in WM will not be excessive.
- When teachers explain new concepts, they can properly review related knowledge that students have learned before, activate related schemata in students’ LTM, and recall these schemata to promote the processing of new concept knowledge by WM which lightens the burden of processing information by WM, conferring a lower load on students in the learning process.
Teaching suggestions:
- Pay attention to improving the learning autonomy of students, promoting enthusiasm and initiative, so that they can put more effort into learning.
- Organize teaching content, firmly grasp the key and difficult points in teaching, avoid content redundancy, effectively control the internal cognitive load, and avoid bringing additional invalid cognitive load to the learning of students.
4.2.1.2.2 External cognitive load
The presentation of learning materials and the corresponding learning activities affect the external cognitive load (Paul, 2002). Teaching progress and rhythm, teaching media, teaching methods, the language of teachers and other factors all influence the external cognitive load. When the way of presenting materials is irrational, students will have a higher external cognitive load, which hinders the progress of learning. Table 4.3 shows the results from statistical analysis of external cognitive load which represent the views of students who were interviewed.
Table 4.3 Statistical analysis of students’ external cognitive load
It can be seen from the table above that in terms of learning time: the views of students about the speaking speed of teachers is 2.92 points, and the load is at lower level, which shows that students feel that the speaking speed of teachers in the class basically meets their requirements, and does not bring too much cognitive load to the students (Feng et al., 1986); the ‘teaching progress and rhythm’ measure had a mean value of 2.74 points, and the load, though still above 2.5 points, is the highest in the dimension of external cognitive load. In the aspect of teaching content presentation: the language score of teachers is the highest, 3.26, and the load is the lowest; the blackboard writing score is 2.80, and the load is the highest in the aspect of content presentation; the scores of teaching media and teaching methods are 2.95 and 2.93, respectively. The load is at the middle and lower level; in addition, many students said that the teaching design, such as the relationship between pictures and words, animation and sound effects, which will also affect their learning.
The reasons for the observed results are as follows:
- Due to the intense biology classes, many teachers speed up the teaching progress in order to catch up with the schedule for the curriculum and there is seldom enough time for students to think and study in the class, which leads to students having no time to watch the learning content and take notes. As a result, they cannot understand the knowledge content well, so the load on the teaching progress is high.
- The language of teachers in the class. It is clear that there is no additional cognitive load brought to students by unclear language expression of teachers, so the load associated with the language of teachers is relatively low.
- Teachers often did not pay attention to the design of blackboard writing after using multimedia resources, and the blackboard writing is not sufficiently neat or clear, which will make students spend limited cognitive resources to see blackboard writing clearly. Undoubtedly, it increases the burden imposed on WM, so ‘blackboard writing’ brings higher cognitive load to students.
- Teachers use teaching methods well, which is more practical in courseware design, and therefore there is no excessive external cognitive load to students’ learning due to improper courseware design (such as messy courseware pages, too many fonts, improper integration of graphics and text).
- The position relationship between pictures and words will affect the attention distribution of students. If pictures and related words are properly integrated and presented together, what students should pay attention to is only the picture and words as a whole, and their attention will be more focused, which is conducive to learning. However, if pictures and words are presented separately and not on the same presentation, students have to try to pay attention to multiple items at the same time, which can lead to distraction of attention and aggravation of WM load, which is also called attention separation effect in cognitive load theory. In addition, too much animation and sound effects will also distract the attention of students, leading to the occupation of cognitive resources in WM by unrelated information, reducing the cognitive resources used to process useful information, thus preventing WM from effectively processing useful knowledge information.
Teaching suggestions:
- Further improve their teaching design. They should organize teaching content according to the key and difficult points of teaching, reduce unnecessary teaching content, and leave enough time for students to study and think, so as to reduce the external cognitive load they experience.
- Pay attention to the design of blackboard writing, to avoid a scenario whereby the processing of knowledge is hindered by untidy, disordered or unclear blackboard writing.
- Improve the level of teaching design, and design courseware, blackboard writing and teaching activities, such as the relationship between pictures and words in courseware, so as to avoid a situation where improper teaching design brings invalid cognitive load to the learning of students (Roxana, 2005).
4.2.1.2.3 Related cognitive load
Properly increasing thecognitive load of students can lead students to invest more effort in learning, promote the construction of concept schemata and improve the quality of learning (Xuebing, 2010).
Table 4.4 Statistical analysis of students’ related cognitive load
| Specific factors | Mean | Std. Deviation | |
| Related cognitive load | Learning interest | 2.89 | 0.91 |
| Emotional arousal level | 2.81 | 0.78 | |
| Metacognitive ability | 3.04 | 0.54 |
From the above table, we can see that in the related cognitive load dimension, metacognitive ability has a mean score of 3.04, with low load; for learning interest, mean score is 2.89, with low load; for emotional arousal level, the mean score is 2.81, with low load. It can be seen that the related cognitive load of students’ learning is at the middle and lower level as a whole.
The reasons for the observed results are as follows:
- The difficulty of high school biology knowledge has increased, and the learning interests of students in biology has declined since middle school according to the answers given in the questionnaires.
- Teachers are not succeeding in stimulating a thirst for knowledge of among students. Students’ initiative and enthusiasm for learning are low, they are not fully engaged in learning, and their efforts in cognitive processing are not enough, so the related cognitive load is relatively low.
According to cognitive load theory, related cognitive load can make learners invest more cognitive efforts in the processing of new knowledge and promote the construction of schemata. Generally, students have high level of learning interests, emotional arousal and a strong metacognitive ability, which can make them invest more cognitive efforts in the processing of conceptual knowledge and use the remaining cognitive resources to construct schemata in depth. Therefore, it is suggested that when teaching, teachers should combine students’ cognitive structures and daily life, arouse students’ interests in learning with real problem situations, enhance students’ emotional arousal level, and make students focus on the learning of conceptual knowledge, so that they can use the remaining cognitive resources to construct the relevant schemata in depth. The following sections in this chapter will discuss the results after the implementation of the suggestions given on how to reduce cognitive load on the experimental group as compared to the control group.
4.2.2 Questionnaire results analysis of teachers
The data collected from 10 questionnaires of the biology teachers were analysed using the SPSS software. The results are shown in table 4.4:
Table 4.4 Descriptive statistical analysis of the teachers’ cognitive load questionnaire
| N | Mean | Std. Deviation | |
| Internal cognitive load | 10 | 2.95 | 0.30 |
| External cognitive load | 10 | 2.99 | 0.41 |
| Related cognitive load | 10 | 2.85 | 0.42 |
From the data presented in Table 4.4, it can be seen that the scores of internal cognitive load, external cognitive load and related cognitive load from the questionnaires of teachers are 2.95, 2.99 and 2.85 respectively, and the cognitive load level of teachers is therefore at the middle and lower level based on the critical minimum value of the cognitive load. It can be seen that most of the teachers can carry out teaching with a positive attitude (Margaret, 2002).
- Analysis of the current situation of internal cognitive load
According to the questionnaires collected from the 10 biology teachers, the following three dimensions of cognitive load are analysed in detail: psychological capital, learning efficiency and learning materials. However, there are differences in each dimension of cognitive load.
Table 4.5 Statistical analysis of internal cognitive load
| Specific factors | Mean | Std. Deviation | |
| Internal cognitive load | Psychological capital | 3.10 | 0.52 |
| Learning efficiency | 3.10 | 0.35 | |
| Learning materials | 3.05 | 0.64 |
It can be seen from Table 4.5 that the internal cognitive load of students based on the teachers responses is high; the load on psychological capital and learning materials, and load on learning efficiency are relatively high and above the minimum critical value of 2.5 (Bruce, 2012).
The reasons for the conclusion of the above analysis are as follows:
- All of the teachers who responded to the questionnaires have a strong sense of competence identity.
- The difficulty coefficient of the biology teaching materials used at present is moderate, the teachers have deep competence knowledge, and have an excellent command of learning materials.
- Combined with students from the experimental group, it can be seen from the internal cognitive load of teachers that they do not fully consider the cognitive ability level of students when organizing teaching content, and therefore only organize teaching content according to their existing teaching experience, so that they may organize learning materials that result in an excessive volume of teaching content and too high a degree of difficulty, which brings greater load to the learning of students, leading to a poor learning effect.
4.2.2.2 Analysis of external cognitive load
Table 4.6 below shows the statistical analysis of the external cognitive load based on the questionnaires answers.
Table 4.6 Statistical analysis of external cognitive load
| Specific factors | Mean | Std. Deviation | |
| External cognitive load | Teaching methods | 2.89 | 0.54 |
| Interaction between teachers and students | 3.16 | 0.36 | |
| Presentation mode | 3.75 | 0.48 |
The data presented in Table 4.6 show that the external cognitive load of teachers is at the middle and lower level compared with the literature (Lee, 2011). In terms of teacher-student interaction, the load is relatively low. Most teachers think that they have interacted well with students in the class, and left enough time for students to study and think. However, this is not consistent with the information fed back by students. Many students think that the teaching progress of teachers is too fast, and the teachers do not give everyone in the class sufficient time for thinking and processing. In the aspect of presentation of learning materials, the load is also at the middle and lower levels. Most of the teachers think that they perform better in the explanation of teaching difficulties, the expression of teaching language and the design of courseware, which is consistent with the views of students. However, in terms of teaching methods, the load is relatively high, few teachers can skilfully use different teaching methods for teaching to ensure that they reduce the cognitive load of students, and most generally have a single teaching method.
The reasons for the above conclusions are as follows.
- The teacher did not really take the students as the main teaching subject when organizing the teaching, did not fully analyse the learners before class, and therefore only organized the teaching from the perspective of teaching, and ignored the priority position of the students, so there was a problem that the teacher thought that there was enough learning and thinking time for the students in the class, but the students thought that the learning and thinking time in the class was not enough.
- The teachers had certain knowledge and skills in education and teaching, but they basically did not adapt to the cognitive characteristics of students when organizing the teaching materials.
- Teachers do not have enough in-depth knowledge of related education and teaching theories or skills, or lack related theoretical knowledge and often cannot flexibly use various teaching methods or strategies and so generally tend to use single teaching methods. The cognitive load imposed on students by this learning method is high.
4.2.2.3 Analysis of related cognitive load
The table below analyses the related cognitive load based on the questionnaires completed by teachers.
Table 4.7 Statistical analysis of related cognitive load status
| Specific factors | Mean | Std. Deviation | |
| Related cognitive load | Learning motivation | 3.00 | 0.33 |
| Study hard | 2.50 | 0.94 | |
| Strategy and method | 2.95 | 0.42 |
The data presented in Table 4.7 illustrate that the related cognitive load of teachers is not high, rather being measured at the middle and low level on average. In terms of learning motivation and strategy, the cognitive load is low. It shows that most of the teachers feel they can adopt certain teaching methods and strategies in class to stimulate and maintain students’ learning interest and motivation, and thus promote effective learning among students. However, from the feedback provided by students, it is evident that their interest in learning is not high, which reflects to some extent that the teaching methods and strategies adopted by teachers do not arouse students’ interest in learning. In terms of learning effort, the load is relatively high, which shows that teachers need to strengthen their theoretical knowledge of education and teaching.
The reasons for the observed results are as follows:
- Although teachers have certain knowledge and teaching skills, they are basically competent for teaching work, so they can adopt certain teaching methods and strategies to stimulate and maintain students’ learning interest and learning motivation, which makes them have low load in learning motivation and strategy methods.
- Most teachers’ awareness of independent learning education and teaching theory is not strong enough, and is something to which they do not pay enough attention. It focuses on the training of improving teaching skills, so the load of learning effort is relatively high.
4.3 A biological concept teaching strategy based on cognitive load theory
A biological concept represents the generalization and summary of complex life activity phenomena. Students will feel the content associated with concepts more abstract and difficult to understand when they study it as compared to basic factual knowledge items. Therefore, in concept teaching, teachers should not only provide students with various, specific and representative examples to help them construct concepts, but also pay attention to students’ prior knowledge and pre-scientific concepts. Then, how should one help students build up scientific concepts on the basis of their ability and cognition? Cognitive load theory pays attention to students’ cognitive structure, using their cognitive structure as a starting point from which to understand and optimize the cognitive load for learning. It is conducive to students’ assimilation and adaptation of concepts, encourages students to build up scientific concepts smoothly, and improves learning efficiency (Mohammed, 2005).
Concept teaching is based on the theories of constructivism and concept transformation. Educational researchers use it in students’ pre-scientific concept transformation or experimental teaching, which greatly develops the theory. This thesis combines concept teaching with cognitive load theory, discusses the corresponding concept teaching path and teaching effect based on the results got from the questionnaires from the teachers on cognitive load theory, enriches and develops applied research on constructivist theory and concept transformation theory in concept teaching, promotes the development of constructivism theory and concept transformation theory, and provides impetus for the teaching reform in high school biology.
4.3.1 Optimizing internal cognitive load
The amount of internal cognitive load is determined by the nature of the learning materials and the knowledge and experience of learners (Bruce, 2012). To optimize the internal cognitive load of the students, teachers must understand the characteristics of learning materials, such as their complexity and the relevance of prior knowledge. In addition, teachers must understand the characteristics of learners, such as their level of knowledge, experience, cognitive ability and emotional characteristics, so that it is possible to reduce the internal cognitive load of their students.
4.3.1.1 Analyse the learning materials and choose the appropriate presentation methods
There are many biological concepts; different types of concepts have different characteristics. In order to reduce the internal cognitive load, teachers should analyse the content of the concept and choose the appropriate presentation according to the characteristics of the concept. The following are some appropriate presentations that teachers can apply.
- Present teaching materials in sections
George Miller, an early researcher of cognitive load theory, found that the largest number of discrete information units that the brain can simultaneously focus on and process is 7 ± 2 (Miller, 1956). When the learning materials are more complex, the learning content can be divided into several segments and presented in sections by dividing the learning content from large units into smaller ones, so as to avoid an excessive amount of learning content at any given time, and consequently reduce the internal cognitive load experienced by beginners. For example, because of the large volume and difficulty of the material related to ‘gene-directed protein synthesis’, when teaching it, teachers can use the method of segmented presentation of materials to deliver the related learning content of ‘transcription’ and ‘translation’ to students in the form of sequential presentation. Using this method, teachers should also provide students with learning examples, and encourage students to understand and use this concept knowledge. Translation will be further studied at a later date; this learning material is therefore foundational and has importance in building more advanced biological knowledge and competence. Considering the difficulty of learning materials, from simple to complex, from easy to difficult, one can consider that block teaching helps learners to effectively process learning materials, so as to understand learning materials (Elvis, 2006). For example, the concept of ‘photosynthesis’ includes lower level concepts such as chloroplasts, the light reaction and the dark reaction. In turn, the concept ‘light reaction’ includes sub-concepts such as photosynthetic pigment, light absorption and light hydrolysis, while the ‘dark reaction’ includes sub-concepts such as CO2 fixation and C3 reduction. When learning this concept, you need to understand its underlying concepts and their sub-concepts. When learning, one needs to first learn simple concepts such as photosynthetic pigment, and the structure and function of chloroplasts, so as to pave the way for learning the process of photosynthesis, and then apply one’s knowledge in the process of photosynthesis and other complex concepts. Thus, photosynthesis should be divided into sub-concepts prior to detailed study being be carried out, so as to make it easier to understand.
- Presentation materials of progressive problem method
According to the theory of cognitive load, it is believed that separating the related information elements and presenting them one after another in teaching can promote learning, rather than presenting all the information elements at once (Hahn, 2011). Research shows that in the absence of related background knowledge of learners, in order to achieve a better teaching effect, the related information elements should be presented separately. The teaching method of progressive problem-solving is a teaching method based on the effect of separating related elements to reduce the internal cognitive load (Lin, 2004). That is, taking problem-solving as the main line of teaching and combining it with the life experience of students to create relatable situations allows problems of interest to students to be created. This provides the foundation for putting forward basic problems, presenting and solving related problems based on the basic problem and finally generating concepts. In this way, the information elements to be learned are separated and presented in the form of problems one by one, so that students can build knowledge in solving the problem step-by-step. This teaching method can help students to construct the concept without as much difficulty and deepen their understanding of the concept (Strasser, 1999).
For example, in the study of ‘mitosis’, in relation to the question: ‘How does a cell ensure that copies of its chromosomes are accurately replicated and evenly distributed between daughter cells?’, around the basic problems, the following related problems can be put forward:
- Why do chromosomes replicate in interphase and shorten and thicken in metaphase?
- Why should the nucleolus disappear and nuclear membrane disintegrate in prophase?
- What is the significance of the star (astral) rays and the formation of spindle fibres?
- What is the role of spindle fibres in pulling chromosomes so that they are arranged regularly on the equatorial plate with their centromeres?
- What is the point of centromeres dividing first, spinning and then drawing chromosomes to the poles of cells?
- What is the significance of cell plate or cell depression, cell constriction, and cell reappearance on nucleolus and nuclear membrane?
In this way, through solving these problems one by one, students can gradually build up the concept of ‘mitosis’, and form a deep understanding of this concept.
- Organize materials according to teaching objectives
The time allocated for high school biology is relatively brief, there are many teaching materials, and the brain can receive and process limited information at the same time. Therefore, when preparing for the class, teachers should make clear the teaching objectives, organize materials and design teaching around the teaching objectives, focus on the key and difficult points of teaching, briefly introduce non-key knowledge, and remove unrelated knowledge and information to avoid excessive demands of learning materials and learning. Students may bring too much cognitive load and need to avoid cognitive overload. At the same time, it can also make the limited cognitive resources get reasonable application. For example, in the discipline guidance, as long as the concept of ‘cell cycle’ reaches the level of understanding, in teaching, teachers should not spend too much time and energy on explaining the concept, but spend more time on helping students to understand the process of cell division. In addition, for learners, they may not know what they need to learn or master in this class; that is, they lack a clear contextual knowledge, which will also increase the internal cognitive load (Kennedy, 2016). Therefore, at the beginning of each class, teachers should let students know what they need to master in that class, so that students can have a clear understanding of the knowledge required for the learning material; teachers can divide knowledge and skills into specific learning steps, and direct students to master each step one at a time. This method can reduce the internal cognitive load.
4.3.1.2 Analyse the characteristics of learners and choose appropriate teaching methods
The antecedent knowledge of learners and their mental state are both important influencing factors of the internal cognitive load, so in order to reduce the internal cognitive load in the learning process, the antecedent knowledge and mental state of learners must first be considered.
The foundational knowledge of learners can promote the construction of new knowledge. If the learner has mastered part of the related knowledge when learning the new concept, then this part of the antecedent knowledge provides support for the learner to learn the new concept. Then, the teachers can activate the related schemata of learners, enable the students to actively recall the related schemata from LTM and connect it with the current learning new schema. The integration of new concepts can reduce the internal cognitive load. In biology class, before explaining a new concept, teachers can start by revising what students are familiar with or understand, before creating progressive problem situations, which gradually direct students to extract knowledge related to learning the new concept, so as to provide support for the construction of new concepts and related schemata. If there is no knowledge related to the new knowledge in the mind of learners, then the teacher can provide related background knowledge, such as providing students with a direct learning plan and helping students to familiarize and sort out the related knowledge, so that they can obtain certain prior knowledge, and can then more easily accept and assimilate the new concept (Diana, 2007).
In addition, the psychological state of learners in the learning process affects the construction of new knowledge. When teaching, it is necessary to analyse the characteristics of learners, so as to understand their psychological state in the learning process. For example, high school students generally have the ability to analyse and to solve problems independently, and their autonomy in learning has been improved as compared with elementary or middle school students.
4.3.2 Reduce external cognitive load
- Choosing appropriate teaching methods
There are many commonly used teaching methods in biology class, including the heuristic teaching method, the inquiry teaching method, the reading guidance method, the practice method, the case teaching method and the task driven method. Although there are many kinds of teaching methods, they should be targeted, comprehensively considered, and appropriate teaching methods that will help students understand concepts without difficulty should be selected. If the concept knowledge is required to reach the level of understanding, the inquiry teaching method or the heuristic teaching method can be selected. This is because both the inquiry and the heuristic methods provide a short-term goal. The teacher is only required to initiate the learning process while the students on the other hand remain active throughout the entire process. They are expected to employ their imaginative and creative skills to solve problems. If it is required to reach the cognitive level of application, the practice method and the transfer method are most suitable. The transfer teaching method is a deep learning method. Representations or examples are made to more similar situations to leverage the new concept with the existing data. According to the characteristics of biological concepts (Reibel, 2003), teachers must choose the appropriate presentation. For example, for specific concepts such as ‘mitochondria’ and ‘chloroplasts’, the students can understand and master them by using the intuitive teaching method. In the study of ‘mitosis’, because mitosis is a microscopic and abstract process, if the process is only displayed and explained orally or by way of pure text, the students will experience high external cognitive load in the process of studying and starting to learn. It is difficult for students to understand biological concepts when they initially begin learning. In addition, teachers should also consider the cognitive abilities, interests, and knowledge level of students, to avoid the selection of teaching methods beyond the cognitive level of students which in turn leads to an increase in the cognitive load on students (Margaret, 2002).
- Optimize the production of multimedia courseware
With the rapid development of modern science and technology, the use of modern education media in the classroom has become the norm, which has brought a lot of convenience to teachers and students. However, if the multimedia resources are not properly used, the method can also backfire. Therefore, in the use of multimedia, especially in the production of multimedia courseware, teachers should abide by the following principles (Haihong, 2013):
- The principle of skilful use of graphics. That is, in teaching, the appropriate use of graphics in the form of presentation of teaching content can help students better understand what they are learning. Mayer pointed out that compared with presenting learning materials only in words, the presentation mode of integrating words with pictures made it easier for students to master the content (Mayer, 2012).
- Based on the channel effect of cognitive load theory, the principle of representation multiplicity considers that visual channel and auditory channel should be fully used when presenting learning materials. Therefore, both visual and auditory materials should be employed to make full use of students’ available cognitive resources (Peter, 1992).
- The principle of proximity holds that attention should be paid to the separation effect when presenting learning materials. When pictures and corresponding words are presented, they should be placed close to each other and presented at the same time. They should not be presented separately from each other in succession. Their presentation at the same time is more conducive to the integration of information.
- The principle of aggregation points out that the multimedia materials used in teaching should play a supporting role, not only to make the materials more engaging, but also to avoid extraneous information taking up the cognitive resources of students and interfering with the processing of useful information.
- The principle of reducing redundancy considers that for the processing of graph, text and voice narration in multimedia courseware, the combination of graph and voice narration is enough for students to understand (Rose, 2008). There is no need to integrate all three together, as this will occupy the cognitive resources of students, and is not conducive to students’ learning (Meg, 2010). For example, when there is voice narration on a video, subtitles are unnecessary (unless some students are deaf) because students can understand the video content by watching the animation and listening to the voice narration. Then, the appearance of subtitles will occupy a portion of the cognitive resources in the students’ visual channel, making the visual channel appear cognitively overloaded.
- Optimize the teaching language and control the teaching rhythm
Language is one of the carriers of information. In teaching, the language of teachers is not only a carrier of information, but also a kind of information. Vague, inaccurate, wordy and other inappropriate teacher language will bring unnecessary external cognitive load to students, and adversely affect the learning efficiency of students. Therefore, teachers should pay attention to the following points in the language they use in class:
- The language of teachers should be accurate in pronunciation and vocabulary, and moderate in volume and speed. Vague pronunciation, random or wrong words, and excessively low volume will affect the teaching effect. Speaking too fast will increase the load on WM during a specific time, and adversely affect the understanding and knowledge mastery of students.
- Teaching language should not be too long-winded. It should be concise and clear to avoid bringing invalid cognitive load to students. At the same time, excessively long-winded language not only reduces the interests of students in learning, but also makes students feel tired of learning and hinders their knowledge processing.
- Teaching language should be vivid, not too abstract or too rigid. In teaching, teachers cannot explain the subject according to the book, as it makes the content feel obscure and difficult for the students to understand. Instead, teachers should use appropriate teaching methods (such as metaphors) to visualize the abstract content and to mobilize the related schemata in the original cognitive structure of students to help them process the knowledge and understand it more easily.
- Teaching language should be hierarchical and orderly, that is to say, logical. It should avoid conferring an increase of cognitive load in students’ learning due to disordered language.
In addition, the rhythm of teaching will also affect the cognitive processing of students. If the teaching pace is too slow, this will prevent students from making full use of their cognitive resources in a specific time. However, if the rhythm is too fast, this forces students to process too much information in a specific time, which eventually leads to cognitive overload and difficulty in processing information effectively. Therefore, in the teaching process, teachers should grasp the teaching rhythm in ways, such as giving students proper thinking time after asking questions, ensuring that students have enough time to process knowledge and information, and helping students build new knowledge smoothly.
4.3.3 Appropriate increase of related cognitive negativity
According to the theory of cognitive load, when cognitive resources are sufficient, the related cognitive load can be appropriately increased to promote the learning of concepts. Related cognitive load is closely related to learning motivation and interest of learners. Therefore, in concept teaching, the introduction of concepts in the way of background introduction or situation introduction can stimulate desire for knowledge of students, enable students to actively participate in learning, and make related schemata in LTM be drawn on, thus increasing related cognitive load to promote the learning of concepts (Paas, 2018). For example, DNA fingerprinting will be used in case investigation. Students generally know about the application of DNA in life, but they do not know how DNA plays a role in case investigation. Therefore, when learning the chapter ‘Nucleic acids as carriers of genetic information’, teachers can use this to create teaching situations and ask questions, for example:
- What kind of substance is DNA?
- Why does DNA provide information about suspects?
Thus, this approach can help students to think and naturally enters into class learning. According to the life experience of students, this thesis puts forward some questions to stimulate their desire for new knowledge, arouse their enthusiasm and initiative, increase the cognitive load of relevance, and promote the construction of new concepts.
In the teaching process, different teaching methods can also be used to increase the related cognitive load; for instance, the incentive teaching method, heuristic teaching method, and inquiry teaching method can be employed. The incentive teaching method is designed to give positive evaluation to students who perform well in the teaching process in a timely fashion, so that their learning enthusiasm can be maintained. When their performance is poor, appropriate measures should be taken to stimulate their learning purposes. The heuristic teaching method refers to an approach whereby students can be asked enlightening problems during teaching, which makes students actively participate in learning, enlivening the class atmosphere. The inquiry teaching method is delivered under the guidance of teachers, but with students actively finding problems, solving them and arriving at answers. These teaching methods can stimulate the initiative and enthusiasm of students in learning, causing them to invest more cognitive effort in learning. It also helps students to improve their interest in learning and maintain their learning purpose. In addition, appropriate examples, key words and notes can increase cognitive load and help students to understand and master knowledge.
4.3.4 Results and analysis of self-evaluation scale of experimental class and control class
(1) An analysis of psychological stress level in self-assessment of students
At the end of each class, the psychological stress of students was measured and participants were asked to submit the self-evaluation psychological stress scale in class (see Appendix 3.4 for details). Table 4.8 shows the results of self-assessment scale submitted by students from the experiment class (class 4) and the control class (class 6) after teaching.
Table 4.8 T-test analysis of independent samples of self-assessment psychological stress level of experimental class (class 4) and control class (class 6)
| N | Mean value | Standard deviation
|
p-value | |
| Class 4 | 55 | 5.13 | 1.34 | 0.04 |
| Class 6 | 54 | 5.19 | 1.41 |
From the data in Table 4.8, it can be seen that that there is difference in the mean value at the level of psychological pressure between the experimental class and the control class, and the level of psychological pressure in the experimental class is lower than that in the control class.
The reasons are as follows. Under the guidance of cognitive load theory, the teaching of the experimental class pays more attention to the cognitive load of students. By properly organizing the number of learning content units according to the teaching objectives, and using the learning task segmentation method to present the complex process of mitosis in sections, the internal cognitive load is reduced to a certain extent. The design of multimedia courseware and the design of teaching links are optimized by using the channel effect, attention separation effect and other teaching effects of cognitive load. The experimental approach also applies the presentation of materials such as video explanation and combination of pictures and texts, so as to reduce the interference of unrelated information in learning, reduce the external cognitive load in learning, and direct students to actively construct biological concepts, so as to lighten the load of WM, so that students do not feel too much psychological pressure.
(2) The results and analysis of the difficulty of self-assessment materials of students
The difficulty scale of self-assessment materials of students (see Appendix 3.5 for details) were handed in at the end of each class. A total of 55 copies of the self-assessment scale in class 4 and 54 copies in class 6 are collected. A t-test analysis was conducted to compare the mean values from the two classes, and the results are shown in Table 4.9.
Table 4.9 T-test analysis of independent samples of self-assessment material difficulty of experimental class (class 4) and control class (class 6)
| N | Mean value | Standard deviation
|
p-value | |
| Class 4 | 55 | 5.36 | 1.08 | 0.26 |
| Class 6 | 54 | 5.61 | 1.22 |
It can be seen from table 4.9 that there is no significant difference in the material difficulty as reported through self-assessment between the experimental class and the control class (administered immediately after class). The reason is that students have a certain independent thinking ability to analyse and solve problems, in line with the cognitive load; so the students in the two classes have little difference in the perception of the difficulty of either analysing or solving problems.
4.3.4.1 Performance analysis
After learning the process of plant cell mitosis, students completed the corresponding after-school test questions. The design of the test questions was as follows:
6 single choice questions (3 points per question) + 9 spaces for one filling question (1 point per question) = 27 points in total.
The specific questionnaire is listed as Appendix 3.6. 55 after-school test questions of class 4 and 54 after-school test questions of class 6 were collected. Independent sample t-test analysis was undertaken on the collected data, and the results are shown in Table 4.10.
Table 4.10 T-test analysis of after class test results of experimental class (class 4) and control class (class 6)
| N | Mean value | Standard deviation
|
p value | |
| Class 4 | 55 | 15.7 | 3.97 | 0.001 |
| Class 6 | 54 | 13.1 | 3.97 |
There is a highly significant difference between the performance of students in the experimental class and those in the control class, as measured by the after-school questionnaire. This significant difference between the samples indicates that that the teaching designed under the guidance of cognitive load theory does indeed promote the construction of new concepts among students.
This difference is explicable in that under the guidance of cognitive load theory, by combining cognitive characteristics and existing knowledge and experience of students, for the teaching of the content of ‘mitosis’, the presentation method of segmented learning materials was adopted which involves learning materials being presented by means of video explanation and a combination of pictures and texts, so as to reduce the interference of unrelated information, reduce the complexity of content and improve learning to a certain extent The load on the WM leaves students with sufficient cognitive resources to process knowledge and information effectively, so as to improve learning efficiency and performance.
4.3.4.2 An analysis of the results of the section examination and the term examination in the experimental class and the control class
The results of the section examination and the term test of the experimental class and the control class were collected as the post-test data, and the collected data were analysed using an independent sample t-test, and the results are shown in Table 4.11.
Table 4.11 Grade analysis of section examination and final examination in experimental class and control class
| Class | N | Mean value | Standard deviation
|
p-value | |
| Section examination
|
Class 4 | 55 | 62.2 | 14.9 | 0.047 |
| Class 6 | 54 | 53.1 | 14.6 | ||
| End-of-term examination
|
Class 4 | 55 | 59.8 | 15.9 | 0.030 |
| Class 6 | 54 | 53.1 | 16.1 |
It can be seen that there is a significant difference between the test results from the experimental class and the control class for the section examination (p = 0.047 < 0.05), and between the test results from experimental class as compared to the control class for the end-of-term examination (p = 0.030 < 0.05). It can therefore be concluded that the application of cognitive load theory in senior high school biological concept teaching has achieved certain results, as the results of the experimental class have been improved to a greater extent in comparison to those students who were taught by conventional methods which do not consider cognitive load theory.
The reasons for the above results are likely to be as follows:
- Under the guidance of cognitive load theory, teachers reduce the difficulty of learning content and internal cognitive load to a certain extent by carefully studying teaching materials, analysing learning situations, arranging the number of teaching content items, not including excessive amounts of teaching content, and separating related elements and learning content for complex learning materials (Mladen, 2018). In this way, the learning load of students can be reduced, there is enough time for thinking in learning, and the effectiveness of information processing can be improved.
- By selecting appropriate teaching methods according to teaching objectives, such as the task-driven method, the concept map method, creating multimedia courseware and the optimization of teaching language, the teaching is considered and adjusted according to the principles of skilful use of graphics, which is linked to the principle of reduction of redundancy. Speech together with graphic methods improves the presentation of learning materials, reduces the external cognitive load, prevents the cognitive resources of students from being occupied by unrelated information, provides sufficient cognitive resources for students to process useful information, and enables students to process information effectively, so as to improve the quality of learning.
- When cognitive resources are sufficient, appropriate examples and suggestions are used in concept learning. These are some ways of stimulating students to take notes and increase the relevant cognitive load, thus promoting understanding and application of conceptual knowledge by students. In general, the application of cognitive load theory in concept teaching reduces the load on the WM in the learning of students, avoids the occupation of students’ cognitive resources by unrelated information, and provides sufficient cognitive resources for the information processing of students. It also enables students to process information effectively, promotes their understanding and transfer of concept knowledge, and improves their learning efficiency. Therefore, in the continuous application of the theory, students’ academic performance has improved to a certain extent, making the experimental class better than the control class. However, such experiments need a lot of time to determine how great the differences between the two classes can be.
4.4 The application of PBL teaching mode in natural science teaching
The teaching mode takes problems as the starting point of learning, emphasizes that under the guidance of teachers, learning is set in complex and intentional problem situations, where students can solve authentic problems through group cooperation and learning the scientific knowledge behind the problems. Through consulting and analysing scientific informational materials and undertaking a division of work to solve problems, students deepen their understanding and application of the pertinent knowledge, stimulate their interests and enthusiasm in learning, cultivate their skills in analysing and solving problems, and develop their ability of autonomous learning. In PBL, the motivation of learning comes from the need to solve problems. As a research modality, PBL is a teaching design model, which has the characteristics of problem, process, openness, initiative, independence, and participation.
In terms of its principles, the PBL teaching mode can be used in any course. At present, this teaching mode has been popularized and applied in many schools, and has achieved excellent results. In China, more and more schools are beginning to adopt this teaching mode. Cognitive load is common in any learning process, just like learning motivation, which is one of the important factors affecting the effect of learning. In the development of cognitive load theory over more than ten years, the research on cognitive load in multimedia learning has achieved fruitful results internationally, and related research is also beginning to reach consistent conclusions (Schnotz, & Kürschner, 2007). With the development of education, various new teaching methods continue to emerge. They affect the learning process of students, and also affect the cognitive load level in the learning process. According to cognitive load theory, too much cognitive load can hinder learning (Paul, 2002). Under what circumstances will the new teaching methods increase the cognitive load of students, and how can measures be taken to reduce the unrelated cognitive load and improve the academic achievements of students (Bowen, 2005)? These problems are attracting the attention of the academic community and become a new topic of teaching design research.
In recent years, with the advancement of teaching reform, network teaching has become a topic for discussion in the field of teaching theory and practice. Everything has two sides, network teaching is no exception (Santoso, 2015). This kind of situation often brings misunderstanding to the majority of practitioners, who think that as long as the application of the network learning environment is compliant, it will lead to excellent results. In order to promote the network learning environment smoothly, it is vital to study how to maximize its advantages and avoid its negative effects. Cognitive load, as one of the main factors affecting the learning effect, is an important field of study to inform the scientific understanding of how the network learning environment might have a negative impact on learning.
The teaching evaluation of the PBL teaching mode mainly includes three aspects: the self-evaluation of students, the mutual evaluation of students, and the evaluation of students by teachers. After the end of a module, students need to be evaluated once, and evaluation materials need to be prepared in advance. In the intensive class time, students need to have a certain time reserved for evaluation. Finally, teachers need to evaluate students. This kind of diversified and multi-agent method needs time and energy. It is much more complex than the traditional assessment of a biology lesson. Therefore, it is difficult to carry out comprehensive and objective learning evaluation in the process of a PBL teaching experiment.
4.4.1 Level differences between classes
Each student is an individual with their own thoughts and a distinct personality. Due to the imbalance of development between students, each student shows a different learning level and learning effect in natural science PBL class learning (Ferreira, 2012). Through the comparison between the experimental class and the control class in this study, it was found that the students in the experimental class who experienced PBL have a better response to the teaching than the students in the parallel class where the PBL mode is not used. This is because the current secondary school examination system in Shanghai enters the corresponding grade according to the high and low scores of the secondary school examination. In the same school, according to the principle of teaching students according to their aptitude, the students in the experimental class will be students with a similar learning level and who will be enrolled in the same class for learning. The students in the experimental class are generally equal than those in the control class in terms of learning achievements, knowledge basis, cognitive level and learning habits.
4.4.2 Learning habits of students
The study habit of students is an important influencing factor in the determination of their academic achievement, and an excellent study habit is the cornerstone of excellent study achievement. The students in the experimental class and in the control already have an excellent habit of learning. Most of them have the habit of previewing before class and reviewing after class. They both show strong initiative in learning. In the lessons, the students in both the experimental class and the control class were active in thinking and participated in the inquiry process.
4.4.3 Basic knowledge of students
Before the students of Grade One in senior high school study natural science, their scientific study in junior high school has facilitated the accumulation of certain basic scientific knowledge, which lays a foundational basis for scientific study. However, there are some differences in the basic knowledge levels of each student. In addition, the learning of science in junior high school is only concentrated in grade 6 and grade 7. Students in grades 8 and 9 do not learn science during these final two years of junior high school. As a result, the scientific knowledge of students has been largely forgotten when they start senior high school, and the basic scientific knowledge of students is not very reliable (Roth, 2012). Although this part of the content is involved in the scientific learning in junior high school, the learning requirements in junior high school are relatively low, relatively simple and easy to understand, only requiring students to retain basic information about these scientific phenomena, have a general impression and demonstrate perceptual knowledge. However, the teaching of natural science at the early stage of senior high school makes a great leap in difficulty. Students are required to have a scientific and accurate understanding of scientific objective facts, understand their underlying causes, master their essential characteristics, and analyse their evolutionary laws (Stephanie, Allison & Ismael, 2011). Students in the first grade of senior high school may not be able easily to adapt to the difficulty and new way of scientific learning all at once.
4.4.4 The logical reasoning ability of students
The PBL teaching mode takes the problem as the starting point, requiring students to study actively and solve scientific problems through independent exploration and group cooperation, so as to acquire the core knowledge of the subject hidden behind the problem, build the knowledge framework of the subject, and then form the ability to learn independently and refine their problem-solving skills. In addition, in the process of inquiry learning and problem-solving, there is a high demand for the logical reasoning ability of students, and it is difficult to complete the process of inquiry learning without a certain level of logical reasoning ability. Logical reasoning ability not only exists in scientific learning, but is also related to multi-disciplinary learning. For example, it is closely related to mathematical reasoning (Song et al., 2013).
Just as there are no two identical leaves in the world, students are so different and full of unique personality, and the characteristics of each student will be different. For the students who are more lively, cheerful and active, the natural science class under the PBL teaching mode is an excellent stage for exerting their personality and talent. The approach fosters autonomous learning and cooperative exploration, in which they enjoy participating and gain a lot. However, for students who are introverted and shy of self-expression, the science class under the PBL teaching mode is more challenging and difficult. They need to overcome their introversion and timidity (None, 1990), be helped to have deep interaction with fellow students and teachers, and also need courage to express and communicate in the achievement display of groups (Gilbert, 2014).
4.4.5 Difficulties in the application of PBL teaching in natural science teaching
- Teachers’ understanding of PBL teaching varies
With the backdrop of a new teaching reform in the high schools of China in recent years, science subjects now receive more attention and so does the exploration of scientific problems by students themselves. However, in the actual teaching process, some teachers tend to be biased in the implementation of science teaching. The transition from the former ‘mugging’ class to a class that pursues ‘full questions’ is not yet complete. Too many, low-level questions make students tired, making them more difficult for teachers to deal with, given low levels of interest. The result may be that students are afraid to answer questions due to feeling confused, and finally lose interest in learning science altogether. This way deviates from the principle of PBL teaching. The main reason is that some science teachers misunderstood the essential characteristics and functions of PBL teaching. They often think that PBL teaching is question teaching, which is just to ask questions and ignore the independent questions generated by the students. Teaching can become just a form of ‘overfilling’, which undoubtedly adds a greater load to students and is less favourable to the cultivation of learning interest. Therefore, in order to implement PBL teaching correctly, science teachers must have an accurate grasp and clear understanding of it, which requires higher competence quality and ability of science teachers.
- Teachers faces great challenges in creating problems
The main processes of PBL teaching are the selection of teaching materials, the design of problems, the process of teaching, and the evaluation of teaching (Koffi, 2012). Scientific problem situations come from life and they are taken from textbooks and are not constrained by textbooks. Designing an appropriate problem is the key to the success or failure of PBL. How to ensure that the problems designed by teachers meet the requirements of these new teaching standards and teaching objectives and how to make the students interested and have the initiative to explore are among the major challenges of implementing the process of PBL teaching. Science teachers need to have a higher ability to create situations and guide problem design.
- The time-consuming nature of PBL teaching is inconsistent with the intense scientific class hours
There are still some gaps between the indications and recommendations of academic research and the actual situation of high school science education, so it is difficult to implement without difficulties. The successful implementation of PBL teaching still needs more activities inside and out of class. Students need to consolidate their knowledge in the process of continuous learning activities and group discussion, which is more time-consuming than traditional teaching, which conflicts with the current arrangement of science courses. The implementation cycle of the PBL teaching mode is long, and it often takes several weeks to complete the implementation of a problem. However, there are many scientific knowledge points and problems, and while the teaching standard gives less teaching time, there remains a large and obvious contradiction between the PBL teaching mode and the actual teaching practice (Karin, 2006).
- Students are accustomed to traditional teaching and lack problem-solving skills and innovation awareness
Under the influence of the traditional culture within the education system, students may show a state of awe and dependence on teachers, a lack of self-confidence, poor initiative and consciousness in learning, and are likely to also lack awareness of problems and innovation. Traditional education pays attention to the standard, emphasizes orderly, uniform and standardized answers, which to a certain extent leads to the lack of innovation consciousness and critical thinking among students, as well as the lack of creativity and novelty formation in the process of thinking and solving problems. Some students are unwilling to present their working or have different ideas but dare not put them forward actively. In this situation of passive learning, it is difficult to carry out PBL teaching based on the independent inquiry of students.
Create problem, create situations to stimulate students’ interests in scientific learning
Problem situations lie at the core of the science of PBL teaching, and also represent the starting point for scientific inquiry and learning. An excellent question situation can arouse the inner feelings of students, stimulate their interest in learning, ignite a desire to acquire knowledge, and mobilize their thinking. In science teaching using a PBL teaching approach, it is necessary for science teachers to first create a problem situation which is based on the purpose of teaching and coincides with the content of the science to be taught, and the problem situation should be both real and complex. Teachers can adopt a variety of ways to create problem situations, one of which is to identify and choose stories or news articles. There are many memorable plots in such publications that reflect scientific knowledge in the real world (Larochelle, 1998).
A second way is to select life examples to inspire students to think about, which can stimulate the learning desire of students, refine common phenomena in life, and cultivate concern among students and thinking about the phenomena around them (Ibrahim, 2015). For example; geostrophic force can also affect weather. When we wash our faces and let go of the water in the basin, how does the water flow down? What is the direction of the flow (clockwise or counter clockwise)? What is the reason?
A third way is to use idioms, proverbs and riddles to create situations; selecting idioms and poems that contain scientific principles can better cultivate an attitude of curiosity and inquiry in science of students, promote their aesthetic interest, and promote their multi-disciplinary knowledge. The poem Why do Qiang flutes complain about willows, and the spring wind does not pass through Yumen pass describes Yumen pass, which is located in the non-monsoon area of China. There are physical features of a location that influence its weather for the warm and humid summer monsoon system, which ultimately does not ultimately reach certain areas. Furthermore, the phrase in the poem ‘One mountain has four seasons’ reflects the vertical zonality of mountains, for which there are well understood physical and biogeographical reasons.
- Create a harmonious atmosphere and encourage students to dare to ask questions
The traditional class is centred on teaching materials, with teachers as the driving force, and with teaching and inculcating knowledge as the primary purpose, and students passively accepting this knowledge inculcation. Such a rigid class atmosphere is not conducive to the development of independent learning skills, the expansion of capacity for original thought or the cultivation of a desire to learn among students. There is a presumption that students should listen to the teacher in the school class. They think that what the teacher says is authoritative. They are afraid to vocalize their inner doubts and lack the foundational abilities for confident questioning. In the science class under PBL teaching, teachers should strive to establish a new type of equal and harmonious relationship between themselves and their students, to provide a relaxed and fruitful atmosphere for learning, so that students no longer feel that teachers represent a superior authority, but rather they are excellent partners in learning. They can then freely express their inner thoughts without psychological constraints. In science class, teachers encourage students to put forward their own questions, so that every student can voice their own doubts, ask their own questions and uphold the attitude of encouragement and appreciation, inspire more guidance, praise more affirmation and learn to appreciate education; this should therefore let students feel that it is a happy and constructive thing to put forward questions.
- Use various means to teach students how to ask questions
Currently in science classes, it is very common that students do not put forward valuable problems in time according to teachers’ ideas around teaching progress goals (Karin, 2006). One of the reasons is that the long-term rote learning leads to rigid thinking among students, which makes it difficult for them to put forward valuable questions. The cultivation and improvement of students’ questioning ability is not achieved overnight. Most students are still in the stage of not questioning. How to cultivate their questioning ability will be an extended and incremental process. In normal teaching and education, teachers should imperceptibly teach students the ways and means of questioning, and direct students to find and put forward questions from multiple levels and viewpoints, so as to reach the state of questioning without fear.
First, teachers should find some questions in the teaching materials. In view of the material analysis in the teaching materials, this enlightens and directs the students to solve problems from different viewpoints and enter into a deeper level of questioning. Second, it is important to look for questions in life practice. Science is inextricably linked with all aspects of life. There are many natural phenomena in daily life that can be explained by scientific knowledge. Teachers should prompt and direct students towards life phenomena, to inspire them to observe life phenomena meaningfully, question these phenomena, and carefully observe, analyse and explore surrounding scientific phenomena (Karin, 2006). For example: why do we see our shadow in the north and the sun in the south? Are all the shadows seen by northern hemisphere residents in the north? Why do we experience shorter days in winter than in summer? Why is the sea warm on a summer evening? Why is the air conditioner hanging on the wall and the heating positioned near the floor? The questions linked to these life phenomena will make students feel that there is science in all of life. Found hidden in the knowledge of life are many scientific phenomena and explanations. Thus, teachers can form the habit of questioning life phenomena as they arise and how they relate to science; this habit can be transferred to students, inspiring them to develop a capacity for independent questioning and problem-solving in the construction of scientific knowledge. Third, there are also questions asked when seeking the cause and the result. When the teacher directs the students to carry out the group cooperation exploration, he should urge the students to study the reason deeply for a certain problem, direct the students to question the formation of the result, so as to improve the questioning level of students. Fourth, reverse thinking cultivates the ability of questioning. In teaching, teachers should explain the problems from the opposite angle, stimulate the thinking and questioning ability of students, direct students to think and explore from the opposite side of things, and use the back-to-back understanding method to learn scientific knowledge to cultivate the questioning ability of students.
- Considering differences of students and designing scientific teaching problems
The problem situation in PBL teaching is close to the life reality of students and should make full consideration of the students’ previous knowledge and experience, as well as the scientific phenomena and scientific environment around the students. Teachers should also try to promote knowledge acquisition and thinking improvement in students using a vivid and specific scientific situation. But the situations close to the lives of students do not mean that there is no difficulty at all in understanding them. The problem in PBL teaching comes from life; however, they are more specific than everyday life problems that people need to solve. It is the expansion and deepening of students’ understanding of life phenomena and must be neither too difficult nor too simple. Under the condition of fully understanding the cognitive level and scientific knowledge foundation of students, the problems set in PBL teaching should be appropriately higher than the current ability of students, with a certain difficulty and complexity, so that students experience certain challenges. With regard to the recent knowledge levels of students, the problem should be properly ‘raised’ so that students can solve it through in-depth thinking and group cooperative learning (under the inspiration of teachers), which is conducive to the improvement of the students’ learning ability.
At the same time, students in different classes have different interests in scientific learning, thinking habits, knowledge and ability basis, and understanding ability. Based on an investigation of the learning situation of students, teachers can balance the setting of problems. The class with better performance can appropriately increase the depth and quantity of problems, but it is better not to cause learning cognitive overload to students, so as to make PBL science teaching more targeted and effective. Effective cognitive theory is achieved when PBL principles are effectively designed and delivered.
- Set up advance organizers to direct students to solve problems step-by-step
The knowledge of the natural sciences is logical and sometimes difficult. Most students lack the imagination space and creative ability to comprehend concepts automatically, so it is difficult for them to understand the knowledge of the natural sciences. For scientific knowledge requiring strong perceptive abilities, teachers can use multimedia equipment or models and other intuitive teaching aids to dynamically display the scientific principles, so that students can understand what they have learned more easily. When students explore and solve problems, teachers can present guiding materials for the more difficult or poorly-constructed problems. This kind of guiding material should encompass the essence rather than the surface connection with problem-solving. That is to say, it should have the internal logical relationship, which provides the preparation for the learning to solve the problem. Content provides a clear direction. The advanced organization of materials can direct students to solve problems, slow down the steep gradient of scientific knowledge acquisition and understanding, reduce the difficulty of knowledge understanding, and improve their thinking depth.
- Reserve enough time for students to fully think about problems
The teacher should control the progress of the class, in order that the rhythm of the whole class is not too fast or too slow, and the pace is relaxed while still maintaining interest. When the group cooperates to explore a scientific problem, the teacher should give the students some space and time to think and discuss, and communicate with their peers in the discussion process. Teachers are responsible for directing the students to use their existing knowledge and life experience to build the methods and strategies to solve the problems. At the same time, a certain amount of time should be reserved for the display and discussion of group achievements. Teachers should encourage each student to actively participate in the communication and display in the class with appropriate ways and means. No matter whether the final results at which the group arrives is excellent or poor, teachers should treat students with appreciation and respect. During the presentation and communication of each group, students should listen to the results of other groups and find out the particularity of the thinking of those other groups, thus arousing the collision of thinking sparks among students, and constantly promoting the optimization of their thinking and the improvement of their results. Further, the time reserved can also allow students to self-digest the knowledge points of this lesson.
- Using mind mapping to direct students to build a knowledge framework
Without appropriate overarching and specific goals in teaching, a lesson can become disordered and confusing. If the teacher does not give the students proper guidance and inspiration in adequate time during the teaching process, then students may deviate from the rhythm of class learning, miss the important content of the class, and finally fail to grasp the scientific learning content and skills. In the process of science teaching through PBL, students may not be particularly systematic and structured when they first start to learn, so this thesis emphasizes that teachers need to pay attention to the reorganization of knowledge as well as the cognitive levels and abilities of their students (Dwyer, Hogan & Stewart, 2010).
The establishment of mind mapping is a conducive all-round and systematic way for students to describe and analyse the problems they are thinking about, which is very helpful to students’ deep and creative thinking of the problems they are studying, so as to find the key factors or key links to solve these problems. Science teachers can use mind mapping to help students build a knowledge framework, which is the re-creation of students’ self-knowledge after their understanding and absorption of new knowledge. In the process of knowledge system construction, students are the masters of learning. Students are not robots, but individuals with ideas and their own unique lives. Their thinking is different and teachers should therefore try to soften the control of students by trying to encourage and promote students’ active participation, asking them to think seriously, direct them to build a meaningful knowledge framework, and complete the internalisation of knowledge (Akinsola, Okebukola & Olugbemiro, 1992).
4.4.7 Advantages and problems of PBL teaching
PBL focuses on building learners’ independence so that they can continue to learn in their future lives and careers. In PBL, teachers are companions of students in the process of problem-solving and participate in the process of problem-solving. They are cognitive coaches of students, who mainly direct students to obtain the strategies for problem-solving, and monitor and direct students’ thinking. Students need to take the lead in problem-solving, playing a role in complex problem situations and actively participating in the whole process. They construct the meaning of knowledge in problem-solving, and form various abilities (such as thinking skills) and personal qualities (such as positivity, self-confidence and cooperation). It has been proved that learners can learn how to acquire knowledge, learn independently, participate in group activities actively and effectively, and become proficient in problem-solving after participating in PBL (Lilik, 2017).
The feedback information provided by the students who participated in the study reported in this thesis shows that the PBL teaching mode embodies several advantages when compared to traditional teaching , mainly in the following aspects: PBL teaching breaks through the traditional teaching idea, and its goal is clearer. The creation of problems directly points out the direction for students and urges them to think continuously which is more conducive to full mobilization of the initiative and enthusiasm of students in their own learning. This environment is conducive to students exercising new skills, which include the ability to learn independently, and analyse and solving problems. The environment also gives them the ability to communicate and express themselves, the spirit of unity and cooperation among themselves and the ability to make bold innovations. At present, the demand for talents in China and many other countries is gradually changing from knowledge-based to ability-based, which is mainly reflected in the requirements for comprehensive ability and comprehensive literacy of students, which is also required by the training objectives of higher education (Lilik, 2017). Teachers should try to relax their control of students and rather encourage them to participate actively.
Nevertheless, PBL teaching is not perfect. In its implementation, there are also some problems worthy of attention (Ferreira, Maria, Trudel & Anthony, 2012):
- PBL emphasizes self-learning with students taking the lead, which requires students to have a certain theoretical basis and abilities such as self-organisation and persistence. However, the long-term implementation of traditional education has created an environment in which some students with poor self-discipline in learning cannot adapt easily, sometimes producing anxiety and psychological conflict, something which adversely influences the teaching effect.
- During the implementation of PBL, teachers’ workload in preparing lessons increases, and students need to spend more time to collect and organize information and create their self-study summaries. In addition, the limited class hours limit the overall potential for the development of PBL in senior high school in China.
- PBL teaching has higher requirements for teachers, and teachers need to have a considerable level of knowledge and skills. This requires that they constantly improve their knowledge structure and overall teaching quality.
- The implementation of PBL teaching requires better teaching resources in larger quantities; the lack of learning resources, computer network resources and teaching software resources in schools will have a direct impact on the learning attitude and learning effect of students.
4.4.8 The quality requirements of PBL teaching for teachers
Teachers are no longer simple knowledge lecturers, but planners, organizers, directors and participants in the whole teaching process. PBL is a kind of teaching method with high requirements for quality among the teachers responsible for delivering it. This modality requires teachers to change their traditional teaching approach, fully understand the essence of PBL and be familiar with its teaching process. It is necessary to give full play to teachers’ organizational, participative and instructive functions, and realize the transformation from ‘teaching’ as the centre to ‘learning’ as the centre. Thus, PBL puts forward new challenges to teachers. Teachers must not only have high-level competence knowledge, competence skills and rich interdisciplinary knowledge, but also strong comprehensive knowledge ability and organizational leadership ability in order to effectively implement the PBL teaching approach.
The following are necessary quality requirements for teachers:
- Correct teaching approach
A teacher’s teaching approach is their directing of action, rational understanding, ideal pursuit and the formed idea system in teaching or educating their students. The rational knowledge, ideal pursuit and educational ideology and philosophy formed by their approach are the educational value orientation and pursuit formed by the educator/teacher in educational practice, thinking activity and cultural accumulation and exchange. This process is a relatively stable, continuous, directional educational and an ideal concept system.
- Design ability of teaching activities based on PBL
For PBL teaching to be carried out effectively, the planning of the whole teaching activity is very important. According to the requirements of the teaching objectives, teachers should carefully select the teaching situation and design the problems around the situation. At the same time, teachers should also plan the whole teaching process. The design of the problems is very important. Baker and Bernhardt (2004) think that problems have two basic characteristics: first, problems are unknown entities in a certain situation; second, these unknown entities have certain social, cultural or technological value. In regards to problems in education, Matthew Lippmann (1986) believed that the problem itself was ill-structured, illogical and complex, and could not have a unique answer. Only in the face of one-sided, fragmentary and imperfect teaching materials can students come to believe that there is a single ‘right’ answer to the problem.
- Organization ability of teaching activities
PBL teaching emphasizes team learning. In the process of teaching, students should be divided into several groups, and each task should be completed by the students in the group. The teacher plays the role of organizer, coordinator and guide. Teachers should let all students participate in the teaching process, encourage every student to participate with confidence, fully mobilize the enthusiasm of every student, and stimulate thinking in every student. However, this is easier said than done, especially where classes have many students. In such a case, it hard to give detailed attention to every single student.
- Teaching evaluation ability
PBL teaching evaluation should be an open system, and should adopt dynamic, diverse and diversified evaluation standards. Because the teaching approach and methods of PBL are quite different from traditional teaching methods, it is not suitable to adopt the traditional ‘closed book’ evaluation method in relation to PBL teaching. Therefore, the existing evaluation method should be changed according to the characteristics of PBL teaching itself. Students should participate in discussion and speech, composition of course learning reports, competence skills assessments, written assessments, and communication ability. These aspects can be regarded collectively as a comprehensive assessment of students’ results. This challenges the evaluation ability of teachers and requires teachers to evaluate students’ performance both comprehensively and objectively.
4.4.9 The necessity and feasibility of PBL in primary school science teaching
The science course is a core course of compulsory education at the senior high school stage which aims at cultivating the overall scientific qualities of students. This course is a comprehensive course, integrating all fields of natural science and technology. This requires that it is essentially different from other courses in terms of teaching content and implementation. However, throughout the current scientific teaching practice, there are many problems, and the current situation of science teaching in China is not optimistic. Historically, more attention has been paid to the teaching of textbook knowledge, while less attention has been attributed to scientific methods, attitudes and values (Lee, 2011). PBL emphasizes that learners should be placed in complex and real problem situations, with ‘problem-solving’ as the core, and should be attempting to solve real problems in groups, so as to acquire knowledge, develop problem-solving skills, and develop the ability of autonomous learning, lifelong learning and group learning. The teaching idea advocated by PBL is consistent with the goal of education reform, and it is more consistent with the learning methods of independent inquiry, practical experience, cooperation and exchange advocated by science teaching.
- The subjectivity status of students
Constructivist learning theory focuses on the main position of students in the learning process, emphasizes that students do not walk into the class with their heads empty, and maintains that teaching cannot ignore the rich experience students have formed in daily life and learning. PBL is a type of teaching based on constructivist learning theory. PBL takes problem-solving as its core and the whole process of problem-solving involves the active participation of students in the learning process, as students become the main driver behind the learning process (in contrast to traditional methods). Teachers are principally the directors and assistants of learning. It follows that in this learning mode, teachers often no longer directly teach knowledge, and students are no longer passively accepting knowledge; rather they are facing the problems put forward by teachers, analyzing and solving problems through their own inquiry, group cooperation or a combination of the two. With the help of teachers, students gradually realize that they are the masters of their own learning. They should acquire knowledge through their own initiative and take responsibility for their learning. When students need help, teachers should give appropriate guidance and provide corresponding learning resources, so as to gradually mobilize the enthusiasm of students. PBL shapes independent learners and increases students’ autonomy in learning. When the students finish the problem-solving activity, they gradually form the ability to think and learn independently (Tasir & Pin, 2012).
- Inquiry in learning process
China’s Compulsory education science teaching standard (2011 edition) clearly points out that science teaching puts inquiry at its core. Scientific inquiry is the essential feature of the scientific research process and has important inherent educational value. The teacher is the supporter and director of students learning science and helps to protect the curiosity of students. The process of learning is not a mechanical acceptance process. Students are faced with real and complex problems, and there is no ready-made knowledge for their reference. In the whole process, students explore problems, acquire knowledge, make assumptions and try to solve problems.
- Comprehensiveness of knowledge
The science course at senior high school is a comprehensive course integrating basic knowledge and skills in the fields of material science, life science, earth and environment science and technology. The purpose of this course is not simply to acquire scientific knowledge, but to improve scientific literacy among students (John & Jr, 2015). The ultimate goal of science teaching is for students to understand scientific knowledge, acquire competency in core scientific methods and acquire the correct scientific attitude. The problems that need to be solved in PBL are complex and come from real life, which requires the integration of knowledge and skills from many disciplines. This is highly consistent with the knowledge content of science teaching. In the PBL environment, students are no longer learning by the unit of class hours and knowledge points, but through the solution of complex problems; they are able to comprehensively think and understand each knowledge point. In addition to the acquisition of scientific knowledge, students gain more from the promotion of scientific methods, scientific attitudes, and the associated scientific values that drive meaningful inquiry.
- Openness of evaluation
Science teaching advocates that students use a wide range of resources in school, within the family and wider society as well as drawing on nature, networks and various media for scientific learning, thus strengthening the penetration and integration of science into the spheres of other disciplines. This requires the evaluation of scientific learning to be open. Scientific evaluation should be a process of combining qualitative with quantitative information and complementing formative with summative evaluation.
- Problem design
The following two points should be paid attention to in the creation of problems design: first, the authenticity and purpose of the problems. The PBL teaching mode attaches great importance to the authenticity of problems. While paying attention to authenticity, one must also be mindful of the purpose of the problems; that is, there is an internal relationship between problems and teaching content and objectives, which also places fundamental demands on teachers in terms of the quality of their teaching. Second, it is vital to pay attention to the cognitive level of students. The problems put forward are first understood by the learners, which is the premise for the analysis of the problems. At the same time, the problems put forward should be solved by the learners through certain efforts. If the problems are too distant from the learners, the process of problem-solving is also laborious.
- Analysis of problems and cooperative exploration
Through the analysis of the problem to putting forward the hypothesis, and thereafter arriving at the problem-solving solution is the premise of all follow-up activities. The problem-solving solution is essentially the activities blueprint for each group, which directs the whole problem-solving process. Therefore, when analysing problems, teachers should fully mobilize the enthusiasm of every student in every group. The grouping of students makes the cognitive load on teachers’ lighter, because the natural subdivision of the class is not as daunting as trying to address each individual if there are over 40 people in the classroom. In the process of cooperative exploration, each member of the group is encouraged to play to their own advantages and cooperate with others in the group. Of course, the guiding role of teachers is essential. Teachers should always pay attention to the inquiry process of each group, provide necessary support and guidance in time, and make the whole inquiry process move towards the established goal.
- Summary and comprehensive evaluation
Each group shows the results of their cooperative inquiry, which not only summarizes the inquiry process, but also provides an excellent platform for mutual learning among groups, between students and teachers, and between individual students. For the learning of students, teachers’ feedback is essential to provide structure and direction. In the face of a dynamic learning process with openness, comprehensiveness and exploration, evaluation should be multi-angled and multi-level. Comprehensive evaluation focuses on the process of problem-solving, and pays more attention to formative evaluation. In addition, the feedback given by teachers should also pay attention to openness and guidance. The criteria of evaluation should not be rigid, but be able to direct students to think and pay attention to the cultivation of innovative thinking.
4.4.11 The integration of cognitive load theory and science teaching based on PBL
Teaching reform is one of the foci of scientific education reform, but not all teaching reform can achieve the expected results; the success or failure of reform measures is often related to the capacity limit of WM. The theory of cognitive load provides ideas and methods for teaching integration, and effectively promotes the assimilation of knowledge. The effect of simulation teaching and case teaching further confirms the value of cognitive load theory in teaching integration, and provides a new theoretical explanation for PBL.
In the reform of science education in China’s teaching system, cognitive load theory plays an important role. The development of cognitive load theory provides more new ideas for the development and reform of science teaching. Worldwide, science education has always been around the three core notions of knowledge, skills, and competence values. The initial impetus for the formation of the modern science education teaching system was the will to create a scientific education system for knowledge, and the focus of its reform was how to lay the foundation for clinical thinking of doctors by increasing the teaching of scientific basic knowledge, especially as described in the Flexner Report of 1910 (Prislin, 2010), which was an important publication in the formation of the modern science education teaching system as it exists today. However, the relationship between knowledge transfer and clinical thinking is not unchangeable; especially when the transfer of knowledge exceeds the bearing limit of memory, knowledge transfer cannot achieve the desired effect. This is also an important reason for the large-scale reform of the science education teaching system in the second half of the 20th century in China.
- Memory and science education
Memory is the basis of learning. For students in science college, the memory of scientific knowledge will accompany the whole learning process. Memory is usually divided into LTM and STM. The latter has a short acting time and relatively small capacity. There is a limit on the number of chunks which it can process, and its primary role is in temporary memory. LTM on the other hand has the characteristics of a long memory time, an almost infinitely large capacity, and is the carrier of knowledge. As a static entity, it can play a role in learning and thinking. Dynamic memory, also known as the WM, plays an important role in learning and thinking.
WM directly participates in the behavioural process. In the past, it has been argued that WM belongs to STM and has little to do with LTM. With the development of recognition memory, there is more and more evidence that WM plays a role through STM, but that LTM also plays a key role in WM. Now some scholars think that WM includes STM and the related mechanism of STM processing. Part of STM is activated from the information stored within LTM, whereas the other part is obtained from the outside world and the part of STM that receives attention from WM (Ball, 2013), while the higher the frequency of information staying in STM, the longer the time it will reside here, and the more easily LTM will be formed.
From the relationship between WM and STM, the latter is also limited by a maximum number of blocks, which is known as the WM capacity (WMC) limit (Thomas, 2006), so in scientific knowledge memory, increasing the efficiency of the use of these blocks in STM is highly beneficial to improving the effect of learning and memory. As with memorizing a random number, it is much easier to memorize it if it is close to a phone number you are familiar with. In this case, the chunks in memory are not increased, but the performance of individual chunks is improved. The same is true of the memory of scientific knowledge, so it also challenges the knowledge in science education. It involves two main problems: one is how to improve the teaching methods used to transfer scientific knowledge to improve the memory efficiency of knowledge; the other is how to improve the efficiency of WM to improve thinking activities of students in ‘real-time’. In reality, these two problems exist at the same time and form a mutually influential relationship.
Traditional science education teaching is based on the subject, the syllabus focuses on the requirements of knowledge points, and the teaching focuses on knowledge transfer in a unilateral sense. This kind of teaching method incorporates a large amount of knowledge, but the WMC of students is limited, and it is impossible to process and store a large number of new blocks of external information in a short time, which also has a negative impact on the teaching effect, so the integrated teaching of scientific knowledge has become a direction for exploration in innovative research and practical settings, such as the one described and analysed in this thesis.
- Cognitive load and knowledge integration
In the first half of the 20th century, the subject-based mode was the main mode of science education. One of the key points of this mode was to improve the clinical thinking ability of doctors by increasing their education of science-based subjects and concepts. Although the exploration of cognition and memory was still in its infancy at that time (Ljunggren, 1987), the negative effect of the lack of connection between the course content and students’ thinking has gradually attracted attention. Some ideas about teaching integration came into being towards the end of the 20th century (Yeung et al., 1997) and were put into practice shortly afterwards.
The integration of teaching according to an organ system is an earlier and more influential integration method. However, after careful analysis, it is not difficult to find that this kind of integration mode does not reduce the capacity of knowledge, and the knowledge content is still relatively independent. While in the later stage of learning, the teaching content is often overlapping, for beginners, the effect of early integration is usually not obvious. Therefore, some people call this integration method ‘teacher integration’. For students, this integration method has not achieved the desired effect (Chen, 2013).
With the development of cognitive theory, Sweller (2005) provided some new theoretical bases for the integration of knowledge in science teaching through cognitive load theory. Sweller’s (2005) theory divides cognitive load into internal load, external load and related cognitive load. The so-called internal load refers to the internal difficulty of the given problem, which is determined by the attributes of the problem itself, having nothing to do with the guidance methods of teachers. External load refers to the difficulty in the guidance process of the given problem, which is directly related to information transmission and guidance methods. For example, the four simple arithmetic operations are obviously conceptually far removed from the inherently difficult content and concepts of calculus, and have nothing to do with the guidance method, and therefore impose a different internal load on cognition. For another example, geometry can be taught by two methods: language description and illustration. The method of illustration is easier for learners to understand. This is the external load of the problem, and the external load can be changed by the teaching method. Later, Sweller (2006) put forward the idea of related cognitive load, which is related to cognitive processes, structure-construction and internalization. The improvement of related cognitive load helps to promote the construction of cognitive structure. Since the sum of the three loads cannot exceed WMC, and the internal load is fixed, it is feasible to increase the related cognitive load by reducing the external load.
In the teaching reform of science education, there are many courses designed by reducing the external load and improving the related cognitive load, but there are some limitations in their use, which mainly come from the knowledge structure itself. For example, anatomical knowledge is mainly declarative knowledge, which has a low internal load, and its so-called difficulty arises more from the huge amount of information. For this kind of teaching, even though teaching reform has been introduced to reduce the external load, it cannot greatly reduce the amount of information to be transferred, and has little impact on the cognitive difficulty of the teaching as experienced by learners. Another kind of situation mainly exists in clinical courses. In clinical teaching, simulation-based learning (SBL) and case-based learning (CBL) have more advantages than traditional teaching. Under the same amount of information transfer, they can effectively reduce the external load of the teaching process and increase the related cognitive load, providing a new mode for knowledge integration in this setting which is worthy of further attention for its potential broader applicability (Wang, 2008).
- SBL, CBL and PBL
Historically, SBL cannot be regarded as being a new or recent thing. As early as the 17th century, the prototype of SBL had appeared; however, the real development of SBL began in the 1960s, and its emergence is almost synchronous with the exploration of teaching integration (Wang & Liu, 2008). The original intention of SBL is to reduce the use of real patients in teaching. With development over time, SBL has been endowed with many new connotations. McGaghie and colleagues (1976) summarized 12 characteristics for SBL, among which high fidelity is the basis of the development of SBL and the important reason why it is superior to the traditional teaching method. High fidelity enables learners to learn in a near-real environment, effectively reducing the external load caused by language description. Teaching with guidance is another important feature of SBL. Environmental simulation is only a change in guidance method, and does not represent the lack of guidance. SBL is not exploratory teaching as guidance is still an important link in the teaching process. The lack of guidance will lead to the increase of external load and the repetitiveness of SBL teaching gives it more application space, especially in the teaching of process knowledge and clinical skills. SBL has advantages that other teaching methods cannot match. In the process of repeated training, the teaching can achieve better results by increasing the related cognitive load in the teaching process. The repeatability of the method makes it more convenient for teachers to provide feedback and evaluate students.
In theory, CBL also plays a role similar to SBL. The terms CBL and PBL are easily confused, because there are problems and problem-solving processes in the course of both processes, and the difference is that PBL adopts the open inquiry mode, while CBL adopts the directed inquiry mode. In recent years, there have been many disputes about PBL, and the understanding of PBL is not uniform. Here are two representative views. Opponents of PBL, such as Kirschner (2002), believe that PBL belongs to minimized instruction teaching. In the process of PBL, students often need to spend more time exploring, and it is not always immediately easy to grasp the key points. This phenomenon exists not only in science higher education, but also in other disciplines and even in secondary and primary education. The supporters of PBL believe in the weight of numerous peer-reviewed research publications which support the application of PBL in education, but they disagree that PBL entails minimum instruction teaching (Song et al., 2013). Proponents of PBL would argue that there are still a lot of materials available to teachers with which to direct students in the PBL process (Davis, 2017).
CBL, which seems to be close to PBL, is actually not the same as PBL. Although most PBL processes have some guidance, PBL explores through open-ended problems. Despite using real cases, the external load of using PBL alone is still very high, similar to giving students the parts of a table and letting students assemble the table by themselves, and then finally providing students with a schematic diagram for its assembly. The concept of CBL is totally different compared with PBL’s exploration; CBL is more like a worked example teaching approach. The information contained in CBL is not only the real case, but also the process of case solving as interpreted by teachers. This process is like giving students a table, which is disassembled by the teacher in front of the students and reassembled by the students according to steps they have witnessed. If necessary, the process can be repeated. For the same teaching goal, the efficiency of CBL is obviously higher than that of PBL, which is also confirmed by related research (Hay & Katsikitis, 2008). Some scholars think that PBL is more in line with the natural thinking process of human beings (Choi, 2004). However, as a kind of vocational education, there are a lot of standardized diagnoses and treatment processes and therefore a relatively fixed thinking mode in science education. It is questionable whether exploratory education is beneficial to this. The practical value of PBL in science education is to supplement, not to replace, guiding education. If CBL is compared to guiding students to make a table, PBL can be thought of as letting students make a table, while acknowledging that they might make a chair. In fact, the practical training value of PBL in science education is more than the exploration value. CBL can effectively reduce the external load of learning, while PBL can improve the related load of learning, and the combination of the two can complement each other.
In today’s (2020) science teaching reform, teaching integration based on cognitive load theory is undoubtedly attractive. Many different teaching systems have been adopted, with different effects and evaluations. Since the beginning of the 21st century, the teaching system which has been dominated by a certain teaching method is gradually starting to undergo real change, and the teaching system of comprehensive application of various teaching methods has been more and more accepted by science teaching scholars, and has become a new direction of teaching reform, and cognitive theory has played an increasingly important role in the reform of science teaching (Hodgson, 1998). The reform of science teaching is significant in this thesis which shows the benefits that were experienced by the experimental group.
4.4.12 Strategies to reduce cognitive load in PBL
With the rapid development of science and technology in modern society, new problems that will need to be solved by students emerge endlessly, and the requirements for cultivating the problem-solving ability of the educated are higher and higher. In July 2001, the Ministry of Education in China issued the Outline of Basic Education Teaching Reform (Trial), which proposed that students’ ability to collect and process scientific information, acquire new knowledge, and analyse and solve problems should be cultivated in the implementation of teaching. It can be asserted that problem-solving is one of the important goals of school education. PBL is a direct way to cultivate problem-solving ability and is worthy of attention for this reason alone. Taking various measures to improve the effect and efficiency of PBL is of great significance to cultivate problem-solving abilities in students. PBL is mainly intended for students to acquire new knowledge and skills by solving a real-world problem. More cognitive efforts are required in the learning process when using PBL as compared to more traditional methods. Too often, when undertaking PBL in science, students are often submerged in the scientific information, confused and overwhelmed with complex problems, or even overloaded to the extent that they wish to give up exploration activities. Most of the time, students are busy searching for scientific information and simply paste a combination of materials found on the Internet, suggesting that they are unable to think deeply and put forward their own independent opinions or even use their own words to describe phenomena, based on a deeper understanding of the conceptual knowledge. It can be seen that the heavier the cognitive load the more negatively the PBL effect may be influenced. One of the important reasons, therefore, for taking measures to reduce the cognitive load in PBL is for its smooth and effective implementation.
Although PBL has its own advantages, it inevitably has defects. In the literature review and the research reported in this thesis, it is found that there are some problems in the implementation of PBL, such as: students becoming distracted because of the temptation of scientific information unrelated to learning in the network; students lose interest in learning because of the frustration of exploration; students feel that learning pressure is great in the process of solving the problem, and yet they cannot bear to give up learning. These problems make the implementation of PBL difficult, and often make front-line teachers ‘stay away’ from the wide application of PBL. This thesis also analyses the negative effects of PBL on an individual’s cognitive system from the perspective of cognitive load. The following strategies should be applied to reduce cognitive load:
- Avoid processing unrelated scientific information
When making a journey, in order to reduce the load of carrying luggage, the easiest way to think of is to pack lightly and ‘simplify’ the items. Similarly, in order to reduce cognitive load, reducing unnecessary scientific information processing is also the most direct measure. In the process of learning, any factors that may increase cognitive load and have no connection with learning should be avoided. Therefore, this strategy can be regarded as reducing the total cognitive load by reducing external cognitive load. The specific measures that can be taken to mitigate excessive cognitive load are described below.
First, educators should ensure that learners have the operation skills of science and information technology. Before entering into the problem-solving learning experience, teachers should ensure that learners have mastered these basic functional skills, so that computer operation becomes an automatic action. In this way, in the process of learning, WM can unconsciously or less consciously extract scientific information in this area, and students can put more energy into solving problems. If the operation of science and information technology and new learning content are learned at the same time, the cognitive load will be increased (Eiriksdottir, 2011).
Second, teachers should provide a clear knowledge structure chart. In network learning, in order to give full play to the advantages of the network to support students’ learning, it is generally necessary to provide students with a variety of learning resources. If the organization of knowledge structure is illogical and too scattered, students need to expend energy to sort out the relationship between various kinds of knowledge before learning can begin, which aggravates the cognitive load. In addition, the scattered and unsystematic knowledge in LTM will bring difficulties when it comes to its extraction when recall is required. Therefore, in the network learning environment, a large number of learning resources should be organized according to the form of knowledge structure, so that the relationship to new knowledge is clear at a glance, and it is convenient for students to build structured knowledge.
Third, it is important to reduce the need for students to jump from page to page. Learning materials in the form of hypermedia require students to spend cognitive resources to memorize learning paths. The more complex the relationship between pages in learning websites, the more jumps, the more energy students need to spend on memorizing learning paths. Therefore, in the network learning environment, teachers should try to reduce need for jumps between pages in order to conserve students’ cognitive resources for related learning.
- Motivating learning
The openness and richness of scientific information may consume limited attention resources of students, lead to unnecessary working, and thus increase cognitive load. To stimulate the learning motivation of students, students, on the one hand, can focus their limited attention resources on learning problems to be solved and reduce unnecessary efforts. On the other hand, teachers can make students willing to devote more cognitive efforts to solve problems, enhance cognitive motivation, speed up the operation of WM, increase related cognitive load and reduce overall cognitive load level. The following measures can be taken to stimulate learning motivation and attract the attention of students:
First, one must strive to improve the challenge and significance of the problem. The problem should be consistent with the existing knowledge and experience of learners but only to a medium degree, so that the learners can understand some elements of the problem. In this way, self-confidence is stimulated and the desire to explore and a willingness to pay more attention to problem-solving results.
Second, the problems should be related to the real lives of students as much as possible. Integration of academic problems to be solved with students’ daily life experience can allow them to fully explore the inquiry topics suitable for their age characteristics and ability levels, which consequently stimulates students’ interest in learning, and triggers greater cognitive efforts (Lilik, 2017).
Third, presenting learning materials in various forms according to the cognitive law is a pivotal aspect of learning, as changing to irrelevant things that are more likely to unintentionally attract the attention of learners is detrimental to learning. Attention of students can be fully aroused by changing the layout, font, form and other factors of learning materials thoughtfully.
- Memory activity transfer
Memorizing scientific information is the basis of processing scientific information. WM must retain some necessary scientific information while processing scientific information. By transferring memory activities, on the one hand, WM can expand the limited capacity of STM; on the other hand, it can enhance the function of LTM and with the help of the powerful search function of a computer, it can reduce the load of WM to extract scientific information from LTM.
Scientific information disorientation is a common manifestation of cognitive overload. The main reason for its occurrence is that the scientific information about the learning path weakens or even disappears in WM, leading to a situation where students do not know ‘where they are lost’. The main forms of scientific information confusion are ‘where’, ‘when,’ and ‘how’? These orienting questions can give full play to the advantages of computer memory and interaction, and transfer the memory work related to the scientific information of a particular learning path to the computer, so as to reduce the corresponding cognitive load experienced during the learning process. Specifically, the strategy of ‘turning off’ can be realized by building a scientific information path map. In addition, it is widely accepted that page jumps are one of the most important factors which can cause an unwanted increase in cognitive load, and even cognitive overload. According to the form of expression of confusion, the scientific information path map has the following functions. First, it displays the whole picture of the scientific information structure in the website in the form of a directory tree, so that students have a clear understanding of the content of nodes, the relationship between nodes, and the overall outline of nodes. Second, it is possible to track the access path of students, and dynamically update and display the historical learning path in different colours in the panorama of scientific information structure. Third, in the panorama of scientific information structure, one can emphasize the current position of students. In the process of browsing scientific information, the scientific information path map is displayed in one corner of the screen in the form of a floating window, so that students can view it at any time when they need it, and can select the direction and destination of the jump accordingly.
Problem-solving is the process of narrowing the gap between the initial state and the target state of the problem through a series of intermediate operations. Therefore, in the process of problem-solving, students need to keep in mind the initial state and target state of the problem. In order to achieve accurate problem representation and reduce the burden on STM, students can list the goal of problem-solving, the known conditions of the problem and the relationship between them in the form of tables. The problem-solving process releases the space in the STM of students, and enables students to explore solutions to problems without having to keep in mind the known conditions and goals of the problem.
In the process of seeking solutions to problems, WM as a ‘workshop’ for scientific information processing needs to accommodate multiple blocks of scientific information temporarily. An e-notebook can be provided within the project learning website, so that learners can record their inspiration and ideas at any time, and save the intermediate results of the problem-solving process. This not only expands the space of WM, but also reduces the pressure on STM, and helps visualize the intangible knowledge stored in the memory system, which is convenient for the extraction of scientific information.
Although the capacity of LTM is theoretically infinite, this does not guarantee that it contains all the knowledge needed to solve the problem, nor that it can be readily accessed (Ericsson & Kintsch, 1995). Even if the LTM contains the required knowledge, if there is no effective ‘cataloguing’, knowledge extraction may also need to consume certain cognitive resources. Therefore, using computers to provide rich learning resources can make up for the defects of incomplete scientific information in LTM, and the powerful retrieval function of computers can save the cognitive resources necessary for extracting scientific information. Specifically, in addition to providing a lot of knowledge related to problem-solving, the learning environment can also provide tools such as maps and dictionaries according to specific learning needs, thereby enhancing the function of LTM, and reducing the load imposed by the necessity of extracting scientific information from WM (Nelson, 2008). However, use of computers can increase reliance on devices and reduce the complexity and functionality of functional memory in students over time.
- Cognitive activity transfer
The process of problem-solving is the process of transforming the initial scientific information into the final state of scientific information through a series of cognitive activities. The more and more complex the cognitive activities that are needed to solve problems, the more cognitive effort must be applied by individuals, and the greater cognitive load will be. Therefore, if the cognitive activities that individuals need to carry out are properly transferred, cognitive load can be reduced. Because the scientific information processing process of computers has some similarities to the cognitive process of the human brain, indeed is more reliable than the human brain for certain types of knowledge, a part of individual cognitive activities can be transferred to computer.
According to different cognitive objects, cognitive activities can be divided into general cognitive activities and metacognitive activities. General cognitive activity refers to the cognition of the object and the processing of scientific information; metacognition refers to the cognition of the individual in relation to his/her own cognitive activity. Different levels of general cognitive activities require different efforts. Some cognitive activities are basic and need relatively few psychological steps, which can be defined as simple cognitive activities. Some cognitive activities require a lot of ‘thinking’ and need to execute a lot of steps, which can be defined as complex cognitive activities (Lawrence, 2018). For example, for the two cognitive activities ‘distinguishing the fourth planet from the sun in our solar system’ and ‘generalizing the pattern or trend from the chart’, the latter requires more psychological steps and mental effort than the former. Therefore, we can define the former as a simpler cognitive activity and the latter as a more complex cognitive activity. The strategies of simple cognitive activity transfer, complex cognitive activity transfer and metacognitive activity transfer are as follows:
- Simple cognitive activity transfer: calculator, spreadsheet
Simple, cognitive activities, although not critical to problem-solving, are also indispensable, and therefore also need to consume cognitive resources. Computers are more efficient than students in completing certain specific tasks. For example, embedding tools such as calculators and spreadsheets into a website to load computing activities can save some cognitive resources necessary for computing activities and may reduce cognitive load (Santoso, 2015). This means that students can have more ‘energy’ to complete complex cognitive activities that machines cannot undertake. Computers cannot fully replace certain human functions, such as creativity and innovative thinking (though AI may be changing this now, we generally accept that the ideas come from humans still).
- Complex cognitive activities are directly related to problem-solving, which necessarily consumes a lot of cognitive resources (Pociask, 2004). For example, in the process of problem solving, the interaction between problem variables is calculated and the hypothesis of problem variable verification is operated. WM is required to reorganize and modify problem variables frequently, which increases cognitive load. WM can reduce the pressure of complex cognitive activities by providing a problem operation model. A problem operation model integrates all problem variables and their relationships. Its functions are as follows:
First, it functions to change abstract problems into concrete ones, and provide students with intuitive operation models. Students test the interaction between different problem elements by changing or reorganizing the problem variables and observing the results. The problem operation model can help students to construct in their minds the problem space and encourage them to develop a deep understanding of the problem;
Second, the results of problem variable manipulation are obtained immediately. Through the problem operation model, students can change the problem variables according to their own ideas, observe the manipulation results in real time, and test hypotheses. The tedious calculation process is omitted.
In short, the intuitive problem operation model may reduce the pressure on students to calculate the middle state of the problem, so that students can focus more on finding the best way to solve the problem, without spending a lot of energy on calculating the possible results of each strategy. At the same time, the space for manipulating problem variables can be expanded, so that the processing and operation of problem variables are less limited by the finite capacity of WM.
- Metacognitive activity transfer
Metacognition is the cognition of cognition (Flavell, 1985, 57). Specifically, it is about the knowledge of one’s own cognitive processes as an individual and the ability to regulate these processes. Metacognition, that is, the strategy of ‘how to do’, is very important for the process of solving ill-structured problems. It can realize the limitations of understanding, which is related to the success of problem solving. In order to solve the problem successfully and smoothly, in the process of learning, learners need to allocate cognitive resources to monitor their thinking methods and strategies. Therefore, if teachers take measures to reduce the mental effort involved in metacognitive activities under the premise of ensuring the learning effect, it will help to reduce the overall cognitive load level of learners. The strategy of reducing metacognitive load can also be transferred and shared. The contributors can be computers and peers, which is described as follows.
In the process of solving problems, learning direction can provide students with ideas to solve problems, allow students to think about their behaviour carefully, know what knowledge they have, (and what knowledge and ability they lack), or arouse the attention of students to some aspects of the problem, while helping students to monitor their thinking processes and share part of the metacognitive load with their peers. Learning direction is subcategorized into static learning direction and dynamic learning direction.
- Static learning direction
A static learning direction shows the suggestions for the whole learning process in the learning website, to provide ideas for the learning process of students, meaning that they should not be at a loss or unable to start.
- Dynamic learning direction
Dynamic learning direction refers to asking students to tackle their own problems through the use of computers in different learning stages, helping students to focus and monitor their learning. According to the different stages of problem-solving, the auxiliary functions of the ‘problem’ presented to students can be divided into three categories: planning, monitoring and evaluation. Specifically, teachers can judge the problem-solving stage of students according to the current page content within the project learning website, and then show the corresponding problems in the form of a dialog box to help students to self-monitor.
- Peer collaboration sharing in metacognition: Learning Community
Metacognitive peer collaboration transfer mainly refers to the construction of a learning community, so that students can derive inspiration and motivation from mutual communication, and modify their thinking from the feedback they receive in real time, so as to share the individual metacognitive load. The so-called learning community refers to the learning organization composed of their fellow students (as well as teachers and other experts), and they communicate with each other in the learning process, share various learning resources, and construct a dynamic structure through participation in activities, conversation, cooperation, reflection, and jointly completing certain learning tasks. When students work together to solve a challenging problem in the learning community, they will constantly communicate for these problems and share their ideas to solve them. From the perspective of individual students, first, they can get different perspectives from community communication, and expand their thinking in relation to the solving of specific problems. Second, they can confer with other members of the team, observe and test their own learning methods and ideas, and make timely reflection and adjustment. In brief, communication within the team can be used as a reflection and feedback tool for students’ learning, which can help learners carry out metacognition and reduce the load of metacognition.
For the communication of a learning community in PBL, face-to-face, computer-mediated communication or a mixture of the two can be used. The formation of a learning community does not depend only on one’s own view; it needs to take corresponding measures, such as cultivating the cohesion among members of the learning community, providing timely feedback, and undertaking evaluation of the cooperative behaviour of members.
- Reduce the interaction of problem elements
If the problem to be solved is unfamiliar to the students, and there are no ready-made schemata in the LTM to solve the problem, then the interaction degree of the elements within the problem to be solved can have a great impact on the level of cognitive load experienced in the process of solving the problem. If the interaction degree of problem elements is low, it means that each element is not closely related to other elements. When solving problems, it is not necessary to consider many elements at the same time, so the capacity requirement of WM is not very high. If the interaction degree of problem elements is high, and the competence knowledge of learners in this field is relatively lacking, then to understand the problem and solve the problem, teachers must pay attention to many different elements at the same time. These elements are processed in WM at the same time, which will increase its load. In PBL, problems with inferior structure often contain many elements and have a high degree of interaction. According to the classification of cognitive load types, the cognitive load brought by the complexity of learning tasks belongs to the internal cognitive load. Traditional CLT believes that a teaching intervention cannot change the internal cognitive load, because it is determined by the task itself. But teachers can reduce the interaction of problem elements and reduce the cognitive load of students in representing and solving problems by changing the presentation of problems. The specific measures are as follows:
- Analysing the interaction between problem elements: problem structure diagram
In the representation stage and the solution stage of problems with multiple interaction elements, it is necessary to hold multiple amounts of scientific information in WM at the same time, and to clarify the interaction between problem elements. More importantly, this needs a variety of cognitive activities, which aggravates the cognitive load. The problem structure chart contains all the problem elements, and expresses the interaction between the problem elements in an intuitive way to help students understand the problem. Specifically, in the application process, teachers can choose the presentation mode of the problem structure chart according to the difficulty of the learning problems and the characteristics of learners. In the process of problem representation, students can use concept maps, mind maps, and other tools to draw the problem structure map according to their own understanding, to help them clear up complex problems. If the problem to be solved is too difficult or unfamiliar to the students, the problem structure chart can also be presented directly to reduce the pressure of students’ scientific information processing.
- Separating problem elements: sub-problems
For a complex and interactive problem, in order to avoid cognitive overload in the process of solving the problem, teachers can artificially reduce the relevance of various elements in a poorly-structured problem, and thereby reduce the difficulty of the problem. The problem is cut laterally and decomposed into several sub problems. After decomposing the problem, different elements can be presented separately. In this way, students do not have to think about so many elements every time in PBL. By solving a sub problem, they can finally solve the comprehensive problem, thus reducing the cognitive resources that need to be paid in units of time, which may also reduce the cognitive load.
- Gradually presenting problem elements: gradient problem
The interaction degree of the problem elements can be reduced, and the problem can be decomposed vertically. At the beginning of learning, the most basic structure of the problem is presented first, which is called a sketch problem. After the students understand the basic framework of the problem, the problem elements are gradually added, and the problem becomes more and more complex. Finally, the complete problem to be solved is presented to the students. According to cognitive load theory, a schema can be treated as a single element in WM, which can reduce cognitive load. The simple problem in the gradient problem can be used as a schema for students to understand more complex problems, so the gradient problem strategy can reduce the number of elements in WM at any one time. To summarize, gradients make students gradually enter into complex problems, which can help students to represent problems and reduce the difficulty of problems, further improving the teaching effect and maintaining students’ interest and enthusiasm for learning.
Due to the influence of performance level of teachers, the school teaching environment, understanding of students and acceptance of the new teaching mode, and teaching practice time, there are a number of deficiencies in this thesis. For example, due to the limitations of the teaching organization form of the class teaching system, it was not possible to analyse the cognitive structure of each individual student, and only the class as a whole could be analysed which is the reason the thesis only used the mean value and the standard deviation. The cognitive structure of students is difficult to control and the cognitive load state of each student in the class will differ because of the analysis of points. In addition, the short time of this thesis and the limited ability of individual students and teachers was also a constraint. This thesis hopes to contribute to the continued improvement in research on cognitive load theory in biological concept teaching. This thesis holds that these issues should be explored further and in more depth in the future, with the hope that researchers and front-line teachers can use more teaching cases of different knowledge types and different course types to make more detailed research into the guiding role of cognitive load theory in biological concept teaching, which is a long-term process.
Broadening the scope and region of research objects, selecting different regions and different levels of schools for research would contribute a wider knowledge base and strengthen the evidence for the application of cognitive load theory in science teaching. Only by creating research objects and samples at multiple levels can the research results be more extensive and generalizable (Xiang et al., 2007).
It would be beneficial to increase the number of students in the samples that completed the survey, and undertake research on students of different grades and levels. If there is a sufficiently large sample size, the more detailed the experimental data is, the more reliable the results of data analysis and thus credibility of the research results will increase.
It is recommended that the time of applied teaching research should be extended. In the future, related research can expand the research time longitudinally with certain groups. From this thesis, it is clear that the tests conducted during the research were performed better than other previous exams. It would therefore be important for future researches to consider carrying out more t-tests. Future research should also carry out long-term follow-up research on students from more grades and more schools, comprehensively and objectively test the teaching effect of PBL in the teaching of natural science, the change and improvement of problem-solving ability of students, and the application of these abilities in practical problems in life, so as to continuously improve the research results.
By adding more science teaching cases and expanding the types of science class, we can strengthen the empirical research and make the teaching research more extensive and deeper and therefore more reliable and generalizable. The type of class need not be limited. The principles can be used in both general classroom teaching and extracurricular teaching. The teaching effect needs a large number of teaching cases and teaching practice to reflect the phenomena under investigation and how they operate at the population level, rather than for a limited sample only. Future research needs to deliver a large number of teaching cases and expanded diversity in the types of class, so as to extend the coverage of research and improve its applicability.
The conclusions of this thesis are helpful in finding some problems in the practice of cognitive load theory. Further analysis of class materials, including books, will help to enrich the empirical study of cognitive load theory, and may also modify the theory to some extent. Class observation can be used to analyse the cognitive load of students according to the relevant theories of behavioural psychology, which is helpful to enrich the empirical cases of cognitive load theory.
According to the results of practical research, this thesis draws the following conclusions:
First, based on cognitive load theory, high school biological concept teaching can put pressure on the limited cognitive resources of students but used correctly in teaching design to ensure the load is related to the concept knowledge, it can improve learning efficiency.
Under the guidance of cognitive load theory, concept teaching was carried out and in the class performance, students were able to closely follow the ideas of teachers, actively respond to the teacher, all in a class atmosphere which is considerably more active than with traditional methods. Students were able to focus more on the learning of the target content, reduce the attention paid to unrelated information, and make effective and reasonable use of their limited cognitive resources. Students were able to master the concept knowledge more quickly and more consistently, being able to make a correct description of the concept confidently.
Secondly, the teaching path of high school biological concepts based on cognitive load theory were able to improve the academic performance of students, and with the increase of application time, the effect was more significant.
After being taught one important biological concept in senior high school based on cognitive load theory, students put more efforts into learning. They knew the key points of learning and learnt more attentively. They thought seriously about the problems put forward by their teachers and mastered knowledge more quickly and more firmly, and practiced with higher accuracy in class. At the same time, the teaching enhanced the interest of students in biology learning, and lead to them putting more time and energy into biology learning than would have been the case under normal conditions. After using this strategy for one semester, the learning achievement of the experimental class was higher than that of the control class.
Thirdly, based on cognitive load theory, the teaching path for high school biological concepts can reduce the cognitive load on students, reduce the psychological pressure on students, and reduce the difficulty of learning materials (but the degree of difficulty reduction is not large). At the same time, teaching based on cognitive load theory needs to be combined with other teaching methods to get a better teaching effect.
Under the guidance of cognitive load theory, learning materials can be organized, and the difficulty of learning materials can be reduced to a certain extent through task segmentation, and separation of related elements. In the experimental class studied in this thesis, students were more active and enthusiastic about learning, more interested in the learning content, and more participative in the learning environment. They actively participated in learning, actively cooperated with teachers, and steadily completed their learning tasks. The analysis of cognitive load using the students’ self-assessment scale showed that the psychological pressure on students in the experimental class was reduced, but there was no significant difference between the experimental class and the control class in the evaluation of the difficulty of materials. This suggests that it may be difficult to achieve a reduction in the difficulty of materials by using the teaching design for senior high school biological concept-based learning, using cognitive load theory, and this approach will need to be combined with other teaching methods to get the optimal learning effect.
Generally speaking, cognitive load theory can help improve the effectiveness of high school biology teaching, help reduce the unrelated cognitive load in learning by students, help students to construct concepts smoothly, and promote the improvement of learning efficiency and performance of students. At the same time, this thesis also proposes that there are many reasons for the improvement in academic performance of students, such as supervision and encouragement from teachers and parents, the length of time students devote themselves to learning, and the impact of societal and social factor. Therefore, this thesis believes that more samples, larger samples, longer experimental time periods and a deeper level of analysis are needed to draw firm conclusions form the application of cognitive load theory to the teaching of biological concepts in senior high school. Only by studying can we draw a more comprehensive conclusion than can be derived from the extant research and the contribution of this thesis.
Based on the results of previous studies, this thesis summarizes the research background, development process, theoretical basis, connotation and characteristics of the PBL teaching approach, laying a theoretical foundation for the application of PBL teaching in natural science teaching. Combined with the current situation of science teaching in middle school, taking two teaching designs as examples, this thesis attempts to construct a PBL teaching approach suitable for the teaching of natural science. By setting up an experimental group and a control group teaching experiment, a natural science class with PBL teaching is compared with a natural science class employing a traditional teaching mode both taught by the same teacher. The experimental group and the control group were tested with paper and pen, the students were given questionnaires, and some students in the experimental group were interviewed, and the students were evaluated to test the teaching effect of PBL in reducing students’ cognitive load in the teaching of natural science. After analysis, the following conclusions are drawn:
First, the PBL teaching proved to be an effective way of teaching secondary school natural science (at least with respect to the biology topic that was studied). In this thesis, PBL teaching is applied to the teaching practice of natural science, and satisfactory teaching results are obtained, which verifies the operability of the model in natural science. After the implementation of the PBL teaching, the interest levels of students in learning science was enhanced and their enthusiasm for learning science improved. This applied study provides practical cases and experience for the popularization and application of the PBL teaching mode in natural science teaching, and also provides reference for future in-depth study.
Secondly, the PBL teaching was helpful in improving the problem-solving ability and scientific achievement of senior high school biology students. The design of the PBL teaching approach embodied enlightening and hierarchical problems, which enabled students of different foundational knowledge and different cognitive levels to participate in group cooperative learning as much as possible. Such a form of learning helps to enhance problem awareness among students, improve their initiative to solve scientific problems, and cultivate and improve their cooperative learning ability. In scientific teaching practice using PBL, most students can analyse problems from different viewpoints related to the situation of the problem, flexibly combine the knowledge they have learned, use different methods of solving problems, adjust their own ideas in time according to different learning problems, and select the best solution with a targeted view.
Thirdly, the PBL teaching mode was more suitable for students with better scientific foundations to carry out independent and inquiry learning. PBL teaching is applicable to a situation in which students already have a certain basis of scientific learning, have strong logical reasoning ability, and are familiar with each other. Students with a certain foundation of scientific learning can often ensure the smooth implementation of PBL teaching in science, and based on the level of scientific learning of students, they are able to cooperate with the members of their learning groups in order to create effective cooperative relationships. It is a cornerstone of group cooperation and exchange that students are familiar with each other and understand each other, so as to ease efficient communication both within and between groups. Only when the learning content contained in scientific problems has certain comprehensiveness, complexity and transferability can it embody the necessity and value of group cooperative learning and be translated into transferable knowledge and skills (Xiao, 2014).
In order to further improve the conclusion of this thesis, this thesis puts forward the following recommendations.
First, researchers should pay attention to the cognitive structure of students, and endeavour to understand the changes and development of cognitive structure of students in a timely way, understanding that both the learning materials and the cognitive structures of students affect the cognitive load state during the learning process. The learning of high school biological concepts is a long-term process. With the advancement of the learning process, the knowledge of students and their experience and confidence increase and their cognitive structures are strengthened. Therefore, teachers should pay attention to the cognitive structure of students, master the changes of cognitive structure among students and analyze and assess the state of cognitive load, so as to adjust teaching, and organize learning materials and activities, in order to reduce the unnecessary load in learning.
Secondly, the application of cognitive load theory to concept teaching needs to be combined with other teaching methods. The internal cognitive load is determined by the experience level of learners, which is difficult to change, and the nature of learning materials. Then, according to the principle of information ordering of learning materials and the level of knowledge and experience of learners, we can adopt the method of layered teaching, classify students according to their knowledge and experience level, and then adopt different ways of presenting learning materials and learning activities to teach according to students’ different characteristics, so as to reduce the cognitive load brought about by the difficulty of learning materials.
Thirdly, students should be the main starting point in teaching to improve the initiative of students in learning. In the actual teaching process, many teachers in China, under the pressure of the college entrance examinations, often add a lot of additional learning content according to the college entrance examination points, when organizing the teaching content, and this kind of ‘mugging’ teaching ignores the cognitive structure of students. This can in turn create an excessive load on students’ learning and weaken the interests of students in learning. In the teaching process, we should take students as the main starting point, and take into account the characteristics of students to organize teaching, so that cognitive resources of students can be used, so as to improve their enthusiasm and learning initiative and make the class engaged with learning.
In the traditional teaching context, the teacher is the centre and the teaching material is the content. Therefore, in the use of these more conventional teaching methods, most of the methods used have the focus on being taught by teachers, supplemented by practice, and review methods, ignoring the students’ autonomy and initiative. In addition, in the traditional teaching mode, there is often a focus on the study of teaching methods whilst ignoring the study of learning methods, resulting in the unclear purpose and function of learning methods, which seriously affects the science of teaching methods and the purposeful determination of students’ central role. With the development of society and the awakening of students’ subjective consciousness, these teaching methods which pay too much attention to teaching and ignore the study of learning methods are very backward. We must break through the shackles of traditional teaching methods and create teaching methods that can cultivate creative talents to meet the requirements of the times.
The core of PBL teaching is autonomous learning and autonomous development. In order to realize self-learning and self-development, we must start with the reform of teaching concepts. Fundamentally, teachers must establish students’ dominant position in PBL, stimulate their learning motivation, form a lively teaching environment, and attach importance to students’ initiative. This will make the students more likely to explore and become more creative, make them more willing to learn and enjoy the learning process, and this will gradually form a good habit of autonomous learning.
