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Using Cognitive Load Theory to Improve Teaching and Learning of Surgery

Jan L. Plass
Associate Professor, Educational Communication and Technology, and Director
CREATE–Center for Research and Evaluation of Advanced Technologies in Education
New York University, New York, NY

One of the defining characteristics of the human cognitive system is the capacity limitation of our working memory. We know since Miller’s seminal 1956 paper1 that we can only hold a few chunks of information in memory at any given time. Translating this fact into the educational practice of teaching and learning, however, has proved to be more complicated than initially thought. What exactly constitutes a chunk of information? And what kind of information do students process during learning that causes high-cognitive load? Over the past two decades, researchers seeking answers to these questions have developed a capacity theory of learning, known as Cognitive Load Theory, that allows practitioners to resolve these issues for their specific circumstances.

The goal of this article is to first provide brief summaries of Cognitive Load Theory and the types of load it proposes, and then to discuss how some of the most robust principles identified by cognitive load researchers may be applied to surgical education.

Cognitive Load Theory

Cognitive Load Theory is based on the assumption that working memory is limited in its capacity, and that long-term memory can store a virtually unlimited amount of knowledge. In other words, we can encode and store large amounts of information for later retrieval as long as we are able to design learning experiences that take into account the capacity limitations of working memory. Another assumption is that working memory consists of separate sub-components, including one for the processing of visuo-spatial information, such as images, and one for auditory information, such as speech, as well as a central executive.2 The components of working memory are thought to process information in relative independence of one another. The important contribution of Cognitive Load Theory to the field of instructional design is its description of the kind of cognitive load demands placed on these components during learning.

Cognitive Load Theory distinguishes three types of cognitive load. The first type, intrinsic cognitive load, refers to the complexity of the information to be learned. This load is described through the construct of element interactivity--how many related elements does the learner have to hold in working memory in order to understand the learning content?3 Consider, for example, the statement: “It is postulated that the progression of appendicitis is initially caused by an obstruction of the lumen of the appendix.”4 This statement has a relatively high intrinsic cognitive load as it consists of at least five different elements that relate to one another. If one element were removed, the meaning of the statement would be lost. In contrast, the statement “the arterial blood supply will become compromised” only consists of two or three elements and has therefore a low intrinsic load. Intrinsic cognitive load is considered a result of the processing of essential information that directly contributes to learning.5 Because it is linked to the inherent complexity of the subject matter, cognitive load researchers think of intrinsic cognitive load as a property of the instructional materials that cannot be changed.

The second type of cognitive load, extraneous cognitive load, describes the demands on the working memory caused by the way educational materials are designed, both in terms of the presentation of the information and the instructional strategies used. In both presentation and strategy, extraneous load is generated by information that learners have to process even though the information does not contribute to learning, and thus educators aim to decrease this type of cognitive load. Concerning the presentation of the information, extraneous cognitive load is generated, by including into the learning materials, information that is not relevant for the educational goal. Components, such as decorative pictures, advertisements, and even navigational tools or other interface elements, that are not needed while studying this particular material fall into the extraneous load category.6

On the other hand, research has shown that visual elements, such as video footage or an animated depiction of a surgical procedure, can lower extraneous cognitive load (and increase germane load, see following section) compared to a description of procedure that uses verbal information only, see Figure 1 (Carlson, Chandler, & Sweller, 2003).7

Figure 1. Visualization reducing extraneous cognitive load (From WISE-MD Module on Appendicitis, NYU SOM). Published with permission by New York University, School of Medicine.

Figure 1. Visualization reducing extraneous cognitive load (From WISE-MD Module on Appendicitis, NYU SOM). Published with permission by New York University, School of Medicine.

The instructional strategy of a learning activity can induce extraneous cognitive load when the activity requires the learner to hold, in his/her working memory, information required to complete the activity, but that does not directly relate to the content to be learned. For example, asking learners to complete a matching activity to name the different parts of the brain would induce extraneous cognitive load if it used numbers as labels for brain regions and asked learners to remember these arbitrary numbers to provide the matching names.

The third type of cognitive load experienced during the learning process is germane cognitive load. Unlike the other two types of cognitive load, which are imposed upon the learner by the learning materials, germane load describes the mental effort that a learner invests into processing the information. In other words, educators design materials and activities with the aim being the increase of germane load. Research has identified several factors that contribute to a desirable increase of mental effort and chief among them is learners’ motivation. In cases where learners’ intrinsic motivation to study specific materials is low, educators can use approaches to increase extrinsic motivation, such as through study incen-tives or the use of grades. For adult learners, the perceived relevance of the materials will affect their motivation to learn, and the inclusion of real-life examples of how the materials can be applied can increase motivation and, in turn, germane cognitive load.

In summary, specific learning material has an inherent level of intrinsic cognitive load that is a function of the material’s level of complexity. Educators and educational material designers aim to reduce extraneous load, i.e., the processing of task-irrelevant information, and increase germane load, i.e., the amount of mental effort learners invest in processing the educational content. This balance is particularly important when intrinsic load is high. Based on the different types of load, which together comprise the total amount of cognitive load a learner experiences, several principles were formulated and empirically validated that are of relevance to surgical educators. I will focus on the three most robust principles with the strongest effects: the expertise reversal principle, the contiguity principles, and the split-attention principle.

Expertise Reversal Principle

The expertise reversal principle states that educational materials designed for learners with low prior knowledge often are not effective, or may even have deleterious effects, when they are used by learners with high prior knowledge, and vice versa. Imagine, for example, the description of a surgical procedure designed for first-year students. The author of such a description would likely include definitions for specific terms that these students would not yet be familiar with. This design would be effective for first-year students, but for fourth-year students, who have mastered these terms as result of their studies, clerkship rotations, etc., these definitions would be redundant, would not add to their learning, and in some cases even hinder it. Similarly, a text designed for fourth-year students would leave out such definitions and the terms would not be comprehensible to learners who do not know their meaning. Multimedia learning environments offer a way to, at least partially, address this issue by providing such definitions on demand, rather than by default.

Contiguity Principle

The contiguity principle states that learning is improved when related information is presented in close spatial proximity (spatial contiguity principle) and temporal proximity (temporal contiguity). According to the prinicple, when related information is presented in separated form or at different times, learning is reduced. An example for the spatial contiguity principle is the use of labels in visuals. Often, specific areas within a visual are labeled with a number or letter, which is then used in the legend to provide the actual label or explanation. The contiguity principle suggests that extraneous cognitive load can be reduced by integrating these labels with the visual rather than presenting it separately. Figure 2 shows a visual from the WISE-MD modules developed at New York University in which labels are integrated with the visual. This format reduces the visual search required to connect the labels and the visual, which reduces cognitive load.

Figure 2. Visualization with integrated labels (From WISE-MD module on appendicitis, NYU SOM). Published with permission by New York University, School of Medicine.

Figure 2. Visualization with integrated labels (From WISE-MD module on appendicitis, NYU SOM). Published with permission by New York University, School of Medicine.

Split-Attention Principle

The split-attention principle states that learning is harmed when dynamic information from two (or more) different sources is presented simultaneously.

For example, explanations accompanying an animated depiction of a surgical procedure could be represented as printed (onscreen) text or as narration. Because both the onscreen text and the visual information of the animation will initially be processed through visuo-spatial working memory, such a design generates a higher cognitive load than a design in which the text is represented as narration, which is processed through the auditory working memory. Another example is the simultaneous presentation of two sources of dynamically changing visual sources, such as a video and an animation, (see Figure 3). For materials with low intrinsic load, i.e., low complexity of the content, this design might be effective as it allows learners to compare the two representations, especially if learners are able to control the pace of the presentation and, if needed, pause or rewind it.

Figure 3. Presentation of two dynamic sources of visual information (video footage and animation; WISE-MD module on appendicitis, NYU SOM). Published with permission by New York University, School of Medicine.

Figure 3. Presentation of two dynamic sources of visual information (video footage and animation; WISE-MD module on appendicitis, NYU SOM). Published with permission by New York University, School of Medicine.

For more complex material, a better design would allow the learners to superimpose the animation on top of the video footage to avoid them having to split their attention between the two information sources.

Summary and Conclusion

Cognitive Load Theory provides a convenient and effective way to evaluate educational materials with regard to the cognitive load they impose. Surgical educators can use the principles that research has identified based on Mayer’s theory5 as well as on other empirical research, (such as Plass, Homer, and Hayward) to optimize their educational materials.8 The main goal of these principles is to reduce the processing of task-irrelevant information, which can be generated either by the design of the learning materials and their presentation, or by the design of the instructional activities and their task demands. The goal for applying the priniciples to teaching and educational material design is to increase the amount of mental effort involved in the processing of task-relevant materials and construction of related mental models.

References

  1. Miller, G.A. (1956). "The magic number seven plus or minus two: some limits on our capacity to process information". Psychological Review, 63, 81-97.
  2. Baddeley, A.D. (1992). Working Memory. Science, 255, 556-559.
  3. Sweller, J. (1994). Cognitive Load Theory, learning difficulty, and instructional design. Learning and Instruction, 4, 295-312.
  4. Wise-MD Module on Appendicitis, NYU SOM.
  5. Mayer, R.E. (Ed.) (2005). Cambridge Handbook of Multimedia Learning. New York: Cambridge.
  6. Sweller, J. (1988). Cognitive load during problem solving: Effects on learning. Cognitive Science, 12(2), 257-285.
  7. Carlson, R., Chandler, P., & Sweller, J. (2003). Learning and understanding science instructional material. Journal of educational psychology, 95(3), 629-640.
  8. Plass, J.L., Homer, B.D., & Hayward, E. (2009). Design Factors for Educationally Effective Animations and Simulations. Journal of Computing in Higher Education, 21(1), 31-61.
  9. Plass, J.L., Homer, B.D., Milne, C., Jordan, T., Kalyuga, S., Kim, M., & Lee, H.J. (2009). Design Factors for Effective Science Simulations: Representation of Information. International Journal of Gaming and Computer-Mediated Simulations, 1(1), 16-35.

 

Online July 10, 2009