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Keywords:

  • dynamic visualizations;
  • cognitive load theory;
  • labeling strategies;
  • anatomy;
  • education;
  • medical

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. COGNITIVE LOAD THEORY AND INSTRUCTIONAL DESIGN
  5. EFFECTIVE DESIGN STRATEGIES
  6. AWARENESS OF POSSIBLE UNDESIRABLE EFFECTS
  7. REASONING OVER ROTE MEMORIZATION
  8. EVALUATION OF INSTRUCTIONAL MATERIALS
  9. FUTURE RESEARCH DIRECTIONS
  10. LITERATURE CITED

In improving the teaching and learning of anatomical sciences, empirical research is needed to develop a set of guiding principles that facilitate the design and development of effective dynamic visualizations. Based on cognitive load theory (CLT), effective learning from dynamic visualizations requires the alignment of instructional conditions with the cognitive architecture of learners and their levels of expertise. By improving the effectiveness and efficiency of dynamic visualizations, students will be able to be more successful in retaining visual information that mediates their understanding of complex and difficult aspects of anatomy. This theoretical paper presents instructional strategies generated by CLT and provides examples of some instructional implications of CLT on the design of dynamic visualizations for teaching and learning of anatomy. Anat Rec (Part B: New Anat) 286B:15–20, 2005. © 2005 Wiley-Liss, Inc.


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. COGNITIVE LOAD THEORY AND INSTRUCTIONAL DESIGN
  5. EFFECTIVE DESIGN STRATEGIES
  6. AWARENESS OF POSSIBLE UNDESIRABLE EFFECTS
  7. REASONING OVER ROTE MEMORIZATION
  8. EVALUATION OF INSTRUCTIONAL MATERIALS
  9. FUTURE RESEARCH DIRECTIONS
  10. LITERATURE CITED

Utilizations of computer-based anatomical visuals in anatomy instructional programs are expanding in undergraduate and medical education. Their effectiveness in instructional modules and programs has been recognized. Many anatomists have used computer-based technologies, such as QuickTime Virtual Reality (VR), to develop 3D dynamic visualizations (Nieder et al., 2000, 2004; Trelease et al., 2000). Although computer-based interactive imagery is well accepted by students in delivering anatomical information (Khalil et al., 2005b), there is a need for well-designed comprehensive resources that integrate image-based anatomical information and structured textual information (Kim et al., 2003). In addition, the explosion in the use of technology-based instruction without adequate research has led to inconclusive results with regard to the effectiveness of dynamic visualizations vis-à-vis static graphics with regard to learning outcomes (Tversky et al., 2002). Specifically, there is limited empirical research on the principles for designing effective student-controlled interactive labeling strategies. Different types of labeling techniques have been adopted in dynamic visualizations without empirical research that substantiates their effectiveness.

From a cognitive load perspective, dynamic visualizations (e.g., animations) have two critical characteristics that are frequently overlooked when utilizing them for instructional use, namely, effects of duration and displacement. Animated information in most cases is transient and consists of a series of successive elements. Failures in learning from dynamic visualizations can generally be attributed to two factors. The first factor, limited duration of working memory, may preclude retention of only transient information when it is not subsequently used. The second factor, the retroactive inhibition effect, may cause learning of new material to have a negative effect on the retention of previously learned materials. Although researchers have begun to develop an understanding of the perceptual and cognitive processes involved in learning from dynamic visualizations, there is little principled guidance about how to design and use dynamic visualizations to foster effective learning. In addition, there is a need to assess rigorously the effectiveness and efficiency of the developed instructional materials.

In Khalil et al. (2005c), we described in details the theoretical foundation of cognitive load theory (CLT). In this follow-up article, we use the theoretical foundation to establish guiding principles for the creation and the utilization of interactive dynamic visualizations in the teaching and learning of anatomy. This theoretical article presents the fundamental principles of applying CLT to the design of instructional materials, example of effective design strategies for anatomical dynamic visualization, evaluation of instructional materials and future research directions.

COGNITIVE LOAD THEORY AND INSTRUCTIONAL DESIGN

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. COGNITIVE LOAD THEORY AND INSTRUCTIONAL DESIGN
  5. EFFECTIVE DESIGN STRATEGIES
  6. AWARENESS OF POSSIBLE UNDESIRABLE EFFECTS
  7. REASONING OVER ROTE MEMORIZATION
  8. EVALUATION OF INSTRUCTIONAL MATERIALS
  9. FUTURE RESEARCH DIRECTIONS
  10. LITERATURE CITED

According to CLT (Sweller, 1988, 1999; Sweller and Chandler, 1991, 1994; Paas et al., 2003a), effective learning requires alignment of instructional conditions with the cognitive architecture of learners. The latter consists of a working memory (WM) that is limited in capacity and comprises other subcomponents that are partially independent in dealing with verbal and 2D or 3D visual information. In addition, CLT posits that a WM of limited capacity becomes more effective when dealing with familiar material stored in long-term memory (LTM), which consists of schemas that represent automated sequences of actions. This process of activating schema effectively reduces the cognitive load associated with developing an appropriate response sequence based on items held in WM.

CLT recognizes three types of cognitive load: intrinsic, extraneous, and germane (Paas et al., 2003b). Intrinsic load results from elements in the content information or problem situation. Extraneous and germane result from the way information is presented and the circumstances in which it is presented. Extraneous load generally detracts from learning and inhibits the formation of effective schema; germane load is effective and generally contributes to the process of schema construction and automation. Intrinsic, extraneous, and germane loads are additive and the sum should not exceed the memory resources available (Fig. 1), otherwise learning will not be effective (Paas et al., 2003b). Consequently, activities and representations that maximize germane load while minimizing extraneous load should be designed and implemented.

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Figure 1. Total cognitive load. Modified from Cooper (1998).

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The principle of maximizing germane load and minimizing intrinsic and extraneous load should be considered within the limits of available cognitive capacity (mental resources). The following example will illustrate this relationship between total cognitive load and mental resources. If instructional materials are difficult (high intrinsic cognitive load) and if the strategy to present information has created a high extraneous cognitive load, the total cognitive load may exceed the available mental resources (Fig. 2). In that case, learning will be hampered and may fail to occur.

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Figure 2. Relationship between total cognitive load and mental resources. Modified from Cooper (1998).

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Previous studies suggest a variety of instructional strategies that promote the construction and automation of schema, ranging from increasing learner control to visual groupings. Strategies that give learners control while interacting with dynamic visualization sometimes appear to help in decreasing extraneous cognitive load and increasing germane load (Bodemer et al., 2004; Schwan and Riemp, 2004). Principles such as visual grouping (Rieber, 1993), segmentation (Zacks and Tversky, 2001), using multiple modalities (Penny, 1989; Mousavi et al., 1995), placing text and graphics according to contiguity principles (Moreno and Mayer, 1999), and signaling or cuing emphasis (Jeung et al., 1997) also appear sometimes to help decrease extraneous cognitive load. Moreover, to increase germane cognitive load, imagining (Cooper et al., 2001), variability (Paas and van Merriënboer, 1994), subgoaling (Catrambone, 1998), and expectancy-driven instructional methods (Renkl, 1997; Hegarty et al., 2003) have been demonstrated to have a positive effect on learning outcomes. To manage intrinsic cognitive load, scaffolding and whole-task practice (Van Merriënboer et al., 2003) and a two-phase isolated-interactivity strategy (Pollock et al., 2002) have been shown to be effective. Notwithstanding the outcomes of these studies, much empirical work with regard to instructional design and cognitive load remains to be done. More specifically, the effectiveness of dynamic visualizations as they pertain to teaching and learning anatomy is not well established. This is a domain that is especially well suited for investigating the three types of cognitive load and how they impact learning because of the role that visualization plays in anatomical reasoning, the fact that relevant static and dynamic visualizations can and have been created, and teaching and learning anatomy occur in conditions that can be controlled with regard to many of the intrinsic and extraneous cognitive load factors.

EFFECTIVE DESIGN STRATEGIES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. COGNITIVE LOAD THEORY AND INSTRUCTIONAL DESIGN
  5. EFFECTIVE DESIGN STRATEGIES
  6. AWARENESS OF POSSIBLE UNDESIRABLE EFFECTS
  7. REASONING OVER ROTE MEMORIZATION
  8. EVALUATION OF INSTRUCTIONAL MATERIALS
  9. FUTURE RESEARCH DIRECTIONS
  10. LITERATURE CITED

In designing instructional materials, anatomy educators should consider that content information and strategies to present this information posit intrinsic, extraneous, or germane loads on WM of limited capacity and duration. Effective instructional strategies should promote schema construction and automation that free WM capacity. However, due to the fact that advanced learners/experts hold expansive schemas and exhibit high level of schema automation when compared to novices, careful attention should be paid not only in designing instructional strategies for the presentation of content information, but also for the level of learner's expertise. A germane load for novices may be extraneous for advanced learners. Therefore, learners' analysis and content analysis are essential in designing instruction that communicate the knowledge to the learners at the right grain size (Van Merriënboer, 1997).

This section presents examples of effective instructional design strategies based on CLT and learner level of expertise that can be implemented in the design and development of anatomical dynamic visualizations.

Learner Control

Learner control is the strategy to decreases extraneous load by providing the learners the opportunity to control over their interactivity with instructional materials in such a way that they can adapt the instructional material to their cognitive system. Learner control can also be used to engage the learners in active processing of instructional materials to increase germane load. With this instructional strategy, learners can be provided, for example, with the ability to control the pace of presentation of an animated model of a heart or skull, i.e., they can play, stop, and replay the animated frames. In addition, learners can also be provided with the ability to enlarge certain areas of interest in dynamic visual for close examination. Because novices usually cannot distinguish between important and unimportant information, learner control strategy is believed to work better for advanced learners.

Visual Grouping

To decrease intrinsic and extraneous load, break down information presented in dynamic visualizations into smaller segments. For example, an animation that shows the blood circulation can be divided into small sequential segments representing the pulmonary circulation, systemic circulation, and hepatic portal circulation instead of showing all information at once. Another example is to use multiple similar views of the same visual to reduce the number of labeled structure on visuals. The grouping of labeled information is based on labeling specifically associated with the different components that comprise the visuals, i.e., learners are provided with multiple views that only show labeling of the emphasized component. Since information is presented in small chunks, it provides learners the opportunity to develop mental representations that help them overcome the split-attention effect.

Modality Principle

The modality principle is based on using both verbal and visual channels to increase the effectiveness of WM. To decrease extraneous load, present verbal information that accompanies visual material in spoken verbal rather than written verbal. However, as learners receive additional instructions and become advance learners, the auditory information becomes redundant. A video vignette showing, for example, the formation of inguinal hernia should be accompanied by voice narration rather than written text on the screen. The presence of written text will force the learner to split his or her attention between reading the text and viewing the visuals. If control buttons are added to dynamic visuals, advanced learners can avoid the redundant auditory information. Moreover, if learners are given control over the pacing of the presentation, written explanatory text will become more effective than spoken explanatory text.

Contiguity Principle

To decrease extraneous load, present verbal explanation and visual material contiguously to overcome split-attention effect. In presenting verbal information that accompanied dynamic visualization, one should consider both temporal and spatial contiguities. Temporal contiguity improves learning with the simultaneous presentation of verbal and visual materials. To avoid spatial split-attention, verbal explanation of dynamic visualization, for example, of the brain should be placed near the visuals, i.e., text information describing the midbrain, pons, and medulla oblongata should be presented close to the area of the brainstem in the image.

Signaling or Cuing

To decrease intrinsic and extraneous load by providing cues that focus the learners' attention on the relevant parts of the dynamic visualizations. Anatomical details can be highlighted using transparent colors that attract learners' attention to focus on the specific details presented in these visuals. Using transparent colors as part of labeling was seen to be very helpful in separating individual anatomical structures and avoiding confusion (Khalil et al., 2005a). For example, different transparent colors can be overlaid on skull images to delineate the boundaries of the bones of the skull.

Based on instructional goals, the above-mentioned examples can be used as a separate strategy or a combination of more than one strategy. For example, if a simple dynamic visualization is developed to help novice learners differentiate between anatomical structures in a radiological image, signaling strategy might be appropriate. However, if the recognition of anatomical structures is coincided with written description of these structures, signaling and contiguity principle are appropriate. In addition, the type of cognitive load posited by instructional materials and the learner's level of expertise will provide clues for the selection of appropriate instructional strategy. Therefore, it should not be understood that all these strategies are applicable for the design of every dynamic visualization.

AWARENESS OF POSSIBLE UNDESIRABLE EFFECTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. COGNITIVE LOAD THEORY AND INSTRUCTIONAL DESIGN
  5. EFFECTIVE DESIGN STRATEGIES
  6. AWARENESS OF POSSIBLE UNDESIRABLE EFFECTS
  7. REASONING OVER ROTE MEMORIZATION
  8. EVALUATION OF INSTRUCTIONAL MATERIALS
  9. FUTURE RESEARCH DIRECTIONS
  10. LITERATURE CITED

While utilizing instructional strategies, CLT can provide possible solutions to some adverse effects. We would like to draw the reader's attention to recognizing and solving these effects.

Split-Attention Effect

In many instances, especially if a lot of information needs to be labeled in anatomical visuals (e.g., high element interactivity), labeling has been provided by numbers on anatomical images with verbal information corresponding to these numbers below the image. In this kind of labeling strategy, learners must keep the numbers in WM and then search for the corresponding verbal information or vice versa. This process of going back and forth between numbers and verbal corresponding information can be cognitively demanding and impose extraneous cognitive load. WM resources are used to integrate the two resources of information mentally instead of using it for learning.

Redundancy Effect

In integrating verbal information with anatomical diagrams or images, the redundancy effect occurs if the two sources of information are self contained and one of the two sources can provide the information required by the learner. Chandler and Sweller (1991) indicated a redundancy effect when they used a diagram that explains the pulmonary and systemic circulation with arrows indicating the direction of flow together with statements indicating, for example, “blood from the lungs flows into the left atrium.” Because the diagram contained arrows indicating the direction of flow from the lungs to the left atrium, the integrated statements were considered redundant, since information can be understood in isolation, i.e., without reference to the two sources. The integrated redundant information can cause increase in cognitive load. However, it is very important to differentiate between redundant sources of information and multiple sources of information that cannot be understood in isolation. In the latter case, cognitive load can be reduced by physically integrating these multiple sources to reduce split attention.

The redundancy effect should be considered with caution in regard to learner level of expertise. Redundant instructional materials for more advanced learners may be essential to be integrated for novice learners. Kalyuga et al. (1998) found that verbal description that accompanied electric wiring diagrams was essential for novices. However, with increasing knowledge of the circuit diagrams, the verbal material became redundant for advanced learners. In conclusion, it is very important to conduct a learner analysis before designing instructions.

Expertise Reversal Effect

As discussed above, essential information for novices may be redundant for advanced learners. Due to the fact that advanced learners cannot ignore the redundant information, they try to integrate and cross-reference the redundant information with its overlapped schemas that is already stored in LTM. This unnecessary process will exert irrelevant cognitive load that negatively affect learning. This effect has been described by Kalyuga et al. (2003) as expertise reversal effect. Therefore, it is very important to consider the interaction between the instructional technique and the levels of learner experience.

Retroactive Inhibition Effect

Earlier, we outlined two critical characteristics that are frequently overlooked when utilizing animations for instructional use: the limited duration of WM and the retroactive inhibition effect. In some animations, information is presented in a set of different frames without learner control. This type of animated models will necessitate an initial understanding of previous frames (e.g., to construct initial schema in LTM) before learning following frames. In addition, the transient nature of animations imposes a limitation on processing information to be stored in LTM. Learners have a very limited time to study each frame of an animation. Before an earlier frame is transferred to LTM, a following frame has to be processed simultaneously. The latter processing of information interferes in remembering information in the earlier frame. This retroactive inhibition effect (Baddeley, 1997) posits ineffective cognitive load by splitting learner attention.

REASONING OVER ROTE MEMORIZATION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. COGNITIVE LOAD THEORY AND INSTRUCTIONAL DESIGN
  5. EFFECTIVE DESIGN STRATEGIES
  6. AWARENESS OF POSSIBLE UNDESIRABLE EFFECTS
  7. REASONING OVER ROTE MEMORIZATION
  8. EVALUATION OF INSTRUCTIONAL MATERIALS
  9. FUTURE RESEARCH DIRECTIONS
  10. LITERATURE CITED

Learning of anatomy sometimes was wrongly viewed as a rote memorization process. There is the contention that learning of anatomy requires excessive rote memory (Aziz et al., 2002). The main reason for this assumption is due to the fact that while learning anatomy, students are introduced to new medical language that necessitates memorization to build a new vocabulary. However, the learning of anatomy itself is far from being simple vocabulary recitation. In many instances, especially when there is high element interactivity in instructional materials that needs understanding, students try to make short cuts by rote-memorizing anatomical information. This process allows them to retain information in isolation. That is, students tend to decrease the cognitive load by avoiding understanding, which occurs when many elements can be held simultaneously in WM. The process of understanding imposes a germane load essential for appropriate schema construction that will be stored in long-term memory. The reliance on rote memorization is less effective in promoting the construction of schemas that can be automated for further learning. This can be the key reason that explains why students who used rote memorization as their learning strategy retain anatomical information for a shorter period of time. Generally, what we can gain from CLT is to teach for understanding and to promote reasoning over rote memorization (Miller et al., 2002). Instructional strategies should help novice students to build lower-level schema (partial schema) that can later be used to decrease load on WM. While learning progresses, elements in low-level schemas will be combined into high-level schemas. This process will lead to the construction of increasing the number of more complex schemas necessary for skill development.

EVALUATION OF INSTRUCTIONAL MATERIALS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. COGNITIVE LOAD THEORY AND INSTRUCTIONAL DESIGN
  5. EFFECTIVE DESIGN STRATEGIES
  6. AWARENESS OF POSSIBLE UNDESIRABLE EFFECTS
  7. REASONING OVER ROTE MEMORIZATION
  8. EVALUATION OF INSTRUCTIONAL MATERIALS
  9. FUTURE RESEARCH DIRECTIONS
  10. LITERATURE CITED

Thorough evaluation and assessment of instructional materials should not only be limited to students' performances and perceptions. The dimension of the overall cognitive loads measured by a mental effort rating scale (Paas and van Merriënboer, 1993; Paas et al., 2003b) will provide additional information for measuring the instructional efficiency. Mental effort rating scale is a subjective technique in which learners can indicate the experienced level of cognitive load. A nine-point scale developed by Paas (1992) was shown to be valid, reliable, and unintrusive (Paas et al., 1994). The scale is sensitive to relatively small differences in cognitive load. A computational formula developed by Tuovinen and Paas (2004) that includes students' performance on a test, learning effort, and test effort has been used to calculate the efficiency of the instructional condition: E = (P − EL − ET)/√3, where E is the efficiency, P the test performance, EL the learning effort, and ET the test effort.

Learning effort and test effort measures are obtained by the mental effort rating scale. Conventional methods can be used to obtain a measure of student test performance. All these measures should be converted to standardized (Z-scores) before using the above formula.

FUTURE RESEARCH DIRECTIONS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. COGNITIVE LOAD THEORY AND INSTRUCTIONAL DESIGN
  5. EFFECTIVE DESIGN STRATEGIES
  6. AWARENESS OF POSSIBLE UNDESIRABLE EFFECTS
  7. REASONING OVER ROTE MEMORIZATION
  8. EVALUATION OF INSTRUCTIONAL MATERIALS
  9. FUTURE RESEARCH DIRECTIONS
  10. LITERATURE CITED

The overall goal of this future research is to create more advanced types of computer-based and learner-controlled dynamic visualizations that can be adapted to the individual learner's level of performance and their invested mental effort. This kind of research will help in developing comprehensive instructional design principles for dynamic visualizations based on CLT and developing strategies for the use of dynamic visualizations that are adaptive to learner progress and level of expertise. The research should assess the effectiveness of dynamic visualization following the employment of different design and labeling strategies to decrease intrinsic and extraneous cognitive loads that are irrelevant for learning and to increase germane load that is directly relevant for learning. The ultimate outcome of the future research should be improvements in the teaching and learning of anatomy utilizing dynamic visualizations, and practical and principled instructional design guidelines for those interested in developing dynamic visualizations to support learning and instruction in the anatomical sciences.

LITERATURE CITED

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. COGNITIVE LOAD THEORY AND INSTRUCTIONAL DESIGN
  5. EFFECTIVE DESIGN STRATEGIES
  6. AWARENESS OF POSSIBLE UNDESIRABLE EFFECTS
  7. REASONING OVER ROTE MEMORIZATION
  8. EVALUATION OF INSTRUCTIONAL MATERIALS
  9. FUTURE RESEARCH DIRECTIONS
  10. LITERATURE CITED