Cognitive overload is a major obstacle that impedes learning. Overload occurs when the cognitive demands of a task or situation exceed students’ cognitive capacities. Overload is a common occurrence because there are limits on how much information we can think about (process) at one time in our working memory. Moreover, if we don’t process information adequately, we forget it quickly (Chandler & Sweller, 1991).
Consider the cognitive effort needed in a typical class period. Students must select and focus on relevant information, ignore distractions and irrelevant information, organize and integrate new material with relevant prior knowledge, make inferences about how new ideas are related to one another, decide which ideas are important and which are less so, interpret the meaning of graphics, such as pictures, charts and diagrams and reconcile those with the instructor’s oral explanations. As students are doing all this, they also make decisions about what information to record in their notes, and what to do about information they don’t understand or completely missed.
Cognitive load refers to the mental effort involved in processing information, i.e., learning, thinking and accomplishing tasks. Researchers distinguish three types of cognitive load.
- Intrinsic load is the mental effort (processing) needed to perform the basic procedures to accomplish a specific task. For example, reading involves decoding text which is the process of translating written words into spoken words and/or mental representations. Decoding is intrinsic load, a necessary part of reading.
- Generative or germane load is the processing needed to make sense of new information and work through a task. As you read, you need to think about the information and construct an understanding of the ideas. This involves connecting the new information with your prior knowledge, inferring missing information, speculating about the meaning of the information, and so forth. Generative processing is necessary to acquire and retain new knowledge from reading.
- Extraneous load is mental effort involved in processing information that is irrelevant to a learning task. For example, as you read an article, you may be interrupted or distracted. The interruptions and distractions are sources of extraneous cognitive load that require mental effort but do not contribute to learning from the article.
Cognitive overload. Working memory (WM) is our capacity to manipulate information consciously, keeping things in mind while we think about them. Working memory, however, is a limited capacity. We can hold only a few pieces of information in mind at one time. Cognitive overload is a breakdown in learning and thinking that occurs when the cognitive demands of a task exceed our mental resources. In other words, when intrinsic, extraneous, and generative processing exceed WM capacity, we are unable to learn effectively or at all. For example, a person who lacks decoding skills will use much working memory capacity simply to decode text (intrinsic load), leaving less capacity for generative processing to understand the material. Or if we are chronically distracted while reading (extraneous load), we have less working memory capacity available to decode and extract meaning from the text (generative load) because irrelevant information occupies working memory.
By trying to manage cognitive load, teachers can help students use more of their mental horsepower to acquire new knowledge and skills. Optimal conditions are when extraneous load is minimized and when students are skilled in the intrinsic processes associated with the task at hand. This maximizes WM capacity available for generative processing – meaningful learning and thinking.
Tools to identify and assess cognitive load. To support students’ learning we need to identify conditions that cause cognitive load and interfere with student learning. Teachers can use that information to reduce or manage load.
Cognitive task analysis. Experienced teachers may be able to predict what kinds of difficulties students will experience as they learn a new topic. Their predictions may be based on past experience with the topic, knowledge of their students, and knowledge about the difficulty of the subject matter. A tool that can help teachers better understand the cognitive demands of course activities is cognitive task analysis (CTA) (Crandall, Klein, & Hoffman, 2006). CTA involves breaking down an academic task into component parts and identifying the mental processes associated with them.
To illustrate, suppose I give an assignment on the topic of “motivation” in my introductory psychology class. Students read two articles, each of which explains a different theory of motivation, and write a 1-2 page paper in which they apply the theories to several scenarios of typical social behavior. A CTA can help identify the cognitive demands of the assignment, and give me some insight into potential difficulties students might experience. A CTA involves listing the component parts of the assignment and the mental activities associated with each.
Note that the CTA is more than a list of the steps involved in a task. It also identifies the thinking processes involved in doing the task. CTAs, even if they are not perfect, can help teachers identify cognitive processes associated with academic tasks in the course, lectures, reading assignments, exams, projects, and class activities. You can use a CTA to assess students’ estimates of their expertise related to the task and/or use a pretest to assess students’ knowledge and skill related to the task.
- Students’ self-assessment of intrinsic processes. Based on a CTA, make a list of component parts and processes for a course assignment. Ask students to evaluate their familiarity, experience, and knowledge of these. A limitation of this approach is that students may not be able to evaluate themselves accurately.
- Pretest of key cognitive processes. Administer a pretest to assess students’ facility with key cognitive processes in the course. Suppose a course requires students to read original research in the discipline throughout the term. Lack of skill will add complexity (cognitive load) to the course tasks and interfere with students’ learning. Pretesting can identify students’ skill levels and whether they will need supplementary instruction on how to read research.
Techniques to assess extraneous load.
Extraneous load is processing that is unnecessary or irrelevant to learning the task at hand. In other words, extraneous load takes up WM capacity but does not contribute to learning. Teachers inadvertently increase extraneous load in their teaching when:
- course materials, instructions, and presentations are poorly structured and disorganized
- they present too much information too quickly
- they introduce irrelevant information into the learning situation
There is no single instrument that assesses all forms of extraneous load. Below are several techniques that provide information about specific aspects of teaching and the course, e.g., organization and clarity, multimedia presentations, pace, amount of new information, student multitasking, etc.
- The Teaching Clarity and Organization Scale is a 10-item questionnaire in which students assess the frequency of clarity and organization in a course, e.g., “. . . how often does the instructor present material in a well-organized way” (Blaich, Wise, Pascarella, & Roksa, 2016). The questionnaire measures students’ perceptions of global aspects of the course related to clarity and organization. The scale does not pinpoint specific problems but can signal whether some aspects of teaching need to be better organized and clearer. Link to the Teaching Clarity and Organization Scale
- Improving Learning by Reducing Unnecessary Mental Load. Compiled by a group of graduate students, this checklist identifies common sources of unnecessary cognitive load in college classes. It focuses on lecture organization, slides and visuals, and classroom atmosphere and pace. Instructors can self-assess to determine specific aspects of their teaching to modify. Link to Improving Learning by Reducing Unnecessary Mental Load
- Multimedia presentations. Use multimedia principles to self-assess lecture presentations that include extensive slides and multimedia materials (Overson, 2014). Link to Multimedia Principles List
- Student feedback about unnecessary cognitive load. A common source of extraneous load is the pace and amount of new information presented in class. Instructors can assess the class periodically to identify information overload problems. A group of graduate students recommend that instructors ask the following questions (Wieman, 2014).
- Do you feel you have enough time, too much time, or too little time to process new information that is presented and take necessary notes?
- What changes in the way I am teaching would help you learn more effectively from the lectures? Try to be specific and explain the reason for each recommendation.
Survey of Students’ Multitasking Activity. Students contribute to extraneous load when they split their attention between the academic task and another source of information. Non-academic use of electronic devices is a common student-generated distraction in the classroom. Teachers can use surveys to assess the prevalence of media multitasking among their students. Link to Student Multitasking Survey
Summary. All learning requires mental effort. Teachers can’t eliminate cognitive load, but can improve learning conditions by taking steps to:
- reduce extraneous load by eliminating distractions and improving the organization and coherence of their instruction.
- manage intrinsic load by helping students become more fluent in basic processes.
- maximize generative processing by helping students use appropriate strategies to develop understanding and skill.
For recommendations about how to reduce and manage cognitive load see Constraints on Mental Effort and Working Memory.
References
Blaich, C., Wise, K., Pascarella, E.T., & Roksa, J. (2016). Instructional Clarity and Organization: It’s Not New or Fancy, But It Matters, Change: The Magazine of Higher Learning, 48(4), 6-13, DOI:10.1080/00091383.2016.1198142
Chandler, P. & Sweller, J. (1991). Cognitive load theory and the format of instruction, Cognition and Instruction, 8(4), 293-332, DOI: 10.1207/s1532690xci0804_2
Crandall, B., Klein, G., & Hoffman, R. R. (2006). Working minds: A practitioner’s guide to cognitive task analysis. MIT Press.
Overson, C.E. (2014). Applying multimedia principles to slide shows for academic presentation. In V. A. Benassi, C. E. Overson, & C. M. Hakala (Eds.), Applying science of learning in education: Infusing psychological science into the curriculum. Retrieved from http://teachpsych.org/ebooks/asle2014/index.php
Wieman, C.C. (2014). Improving learning by reducing unnecessary mental load. Retrieved from http://www.cwsei.ubc.ca/resources/files/Cognitive-Load_CWSEI.pdf