Cognitive load theory (CLT) is both theory of cognition and learning and a instructional design model. It's main contributor is J. Sweller.
- “Cognitive load theory describes how the architecture of cognition has specific implications for the design of instruction. The theory has broad applications in the design of instructional materials, providing a general framework and conceptual toolkit for instructional designers to minimize and control the conditions that create unwanted cognitive load in learning materials.” (Wikipedia)
- “CLT is concerned with the design of instructional methods that efficiently use people's limited cognitive processing capacity to apply acquired knowledge and skills to new situations (i.e., transfer). CLT is based on a cognitive architecture that consists of a limited working memory with partly independent processing units for visual and auditory information, which interacts with an unlimited long-term memory.” Pass et al. 2003: Abstract.
- “Cognitive load theory can inform the design of web-based instruction. The basic premise of cognitive load theory is that the focus of an instructional module must be the instruction itself. Information that is adjunct to the instruction must be designed to minimize cognitive load and enhance working memory. Because the mental resources of working memory can be overloaded, any information that ignores cognitive load may interfere with the process of acquiring knowledge and skills. Instruction that effectively presents the learning to our working memory has an impact on our ability to store knowledge and skills in our long-term memory. Everything that we "know" is held in our long-term memory” (Feinberg & Murphy 2000:Abstract).
Graham Cooper, one of Swellers co-workers, present CLT as follows:
In recent years there has been an increased focus on the role of education and training, and on the effectiveness and efficiency of various instructional design strategies. Some of the most important breakthroughs in this regard have come from the discipline of Cognitive Science, which deals with the mental processes of learning, memory and problem solving. [Editor Note: Cognitive Psychology. Cognitive Science is usually defined a "the interdisciplinary study of mind and intelligence, embracing philosophy, psychology, artificial intelligence, neuroscience, linguistics, and anthropology" Stanford Encyclopedia of Philosophy ]
Cognitive load theory (e.g. Sweller, 1988; 1994) is an instructional theory generated by this field of research. It describes learning structures in terms of an information processing system involving long term memory, which effectively stores all of our knowledge and skills on a more-or-less permanent basis and working memory, which performs the intellectual tasks associated with consciousness. Information may only be stored in long term memory after first being attended to, and processed by, working memory. Working memory, however, is extremely limited in both capacity and duration. These limitations will, under some conditions, impede learningThe fundamental tenet of cognitive load theory is that the quality of instructional design will be raised if greater consideration is given to the role and limitations, of working memory.
(Cooper, 1998; Source)
John Sweller's work is based on an information processing model of cognition, and in particular the limitations of working memory. In addition,“key learning activities are schema acquisition and automation of their usage. After enough training, acquired schemata are stored in long-term memory. They allow high cognitive performance with a very limited working memory” (Heeb 2001: 3). Now when learning concerns multiple interacting elements of information, they have to be learned at the same time and that is a challenge for educators !
Sweller differentiates between intrinsic, germane, and extraneous cognitive load.
- Intrinsic load is related to the difficulty of concepts, i.e. integral complexity of an idea or set of concepts (learning contents). For example, in programming, learning to program "Hello" with PhP is much easier than doing it with Java.
- Extraneous load (irrelevant) is due to the design of the instructional materials. In inefficient instructional designs it adds unnecessary load. For example, an audio-visual presentation format usually has lower extraneous load than a visual plus text format, because in the former case, working memory has less information to process.
- Germane load (relevant) relates to the degree of effort involved in the processing, construction and automation of schemas. Germane load is sometimes associated with motivation and interest. Intrinsic load is unchangeable, whereas the instructional designer can manipulate extraneous and germane load.
2 Sweller's principles and guidelines for instructional designers
Cognitive load theory suggests preventing students from using a means-ends strategy and encouraging them to attend to problem states and their associated moves should reduce extraneous cognitive load and so facilitate schema acquisition. In general, instructional techniques should attempt to reduce extraneous cognitive load associated with constructing a representation because this facilitates learning.
According to Rebetez (2006:12-13) Sweller, based on his cognitive load theory, describes a series of effects and guidelines to create learning materials:
- Goal free effect: novice learners with a specific learning goal (like a precise question to answer) focus on the goal and pay no attention to other information. This is detrimental to learning.
- Worked examples effect: using known and resolved examples diminish cognitive load and improves comprehension.
- Problem completion effect: the worked out example should be followed by a similar but unresolved problem to maximize motivation.
- Modality effect: two messages on similar elements should be provided through different sensory modalities. Research suggest that more memory capacity is available when dual modalities were used, however it may lead to a split-attention effect and excessive animated multimedia may lead to a general overload.
- Split-attention effect: occurs when learners have to process and integrate multiple and separated sources of information. For instance, a geometrical sketch is better understood when textual information is spatially integrated rather than separated . This effect is very similar to Mayer spatial and temporal contiguity principles (see multimedia presentation
- Redundancy effect: when the same information is presented more than once the multiple processing is negative for comprehension since it increases external cognitive load. If novices can benefit from partially redundant information (integrated text and picture for example), expert's performances can be impaired . These six first effects try to minimize extraneous cognitive load (to reduce the number of cognitive processes involved that are unnecessary for learning).
- Element interactivity effect: interactivity with the material increases negative effects such as split-attention and redundancy effects.
- Isolated interacting elements effect: with complex models containing multiple interacting elements it is advisable to begin with presenting every element separately.
- Imagination effect: mentally simulating the functioning and interaction of elements allow experts to obtain better results.
- Expertise reversal effect: with experts, several effects are inversed. In this case, classical design rules are advisable instead of those based on cognitive load.
- Guidance fading effect: as expertise is obtained, learners should be less guided in their exercises.
3 Limitations of the Cognitive Load Theory
- Many of these ideas are mostly inspired by theories of cognitive processes published in the 70s or 80s. Miller's finding of a limit to the amount of information that can be maintained in short-term memory in 1956 (Short Term Memory @ Wikipedia), Baddeley and Hitch early model of working memory in 1974 (Baddeley's model of working memory @ wikipedia) and Paivio's ideas of a dual-coding storage hypothesis in the early 1970s (Dual-coding theory @ wikipedia), models of attention by Deutsc, & Deutsch (1963) or Kahneman (1974) (Attention @ wikipedia).
- More modern views or more recent findings on working memory and attention are not always taken into account in the most recent versions of the Cognitive Load Theory.
- The recommendations are given in the form of guideline and strong empirical evidence is not always provided.
- This theory has constraints about how memory works at his chore. But the defenders of this theory sometime make very naive or ill-informed statements about what has been learned about memory in the field of Cognitive Psychology. For instance, Dr Cooper states that "Working memory is the part of our mind that provides our consciousness" well, this is a quite original proposal.
4 Other Strategies to diminish cognitive load
- Computer-supported authoring tool could scaffold and facilitate cognitive processes by alleviating the cognitive load.
- In collaboration the persons can share cognitive load by dividing it up into smaller portions. Each of them will be mainly treated by one of the persons.
- Appropriate selection of processing strategies can diminish cognitive load.
On the other hand, the difficulty with metacognitive processes is that they enter into competition with lower cognitive process for resources (especially working memory). Metacognition involves an increased cognitive load. Supporting cognitive and metacognitive processes with tools may benefit the metacognitive layer (which often comes after other attention mechanisms).
These strategies go somewhat beyound the debate on cognitive load in the sense that some instructional design models do not try to minimize intrinsic and germane cognitive load. E.g. some project-oriented learning designs even require that learners are exposed to authentic cognitive load situations and that they learn how to handle this by acquiring appropriate learning strategies. This being said, a designer always should take into account cognitive load and make sure that it is not unnecessarily high.
- The NASA-TLX measures task load (Hart & Staveland, 1988)
- Improving Traditional Instruction. (This is a short, very good introduction).
- Research into Cognitive Load Theory and Instructional at UNSW by G. Cooper (Good Introduction)
- Back, Jonathan and Charles Oppenheim (2001), A model of cognitive load for IR: implications for user relevance feedback interaction, Information Research, Vol. 6 No. 2, January 2001. HTML
- Chandler, P., & Sweller, J. (1991). Cognitive load theory and the format of instruction. Cognition and Instruction, 8, 293-332.
- Cooper, G., 1998, Research into Cognitive Load Theory and Instructional Design at UNSW, University of New South Wales, Australia, 
- Cooper, G. "Cognitive Load Theory as an Aid for Instructional Design." Australian Journal of Educational Technology. 6:108-113, 1990.
- Chiperfield, Brian, Cognitive Load Theory and Instructional Design, HTML (Nice example)
- Feinberg, S. and Murphy, M. 2000. Applying cognitive load theory to the design of web-based instruction. In Proceedings of IEEE Professional Communication Society international Professional Communication Conference and Proceedings of the 18th Annual ACM international Conference on Computer Documentation: Technology & Teamwork (Cambridge, Massachusetts, September 24 - 27, 2000). ACM Special Interest Group for Design of Communications. IEEE Educational Activities Department, Piscataway, NJ, 353-36 Abstract / PDF (Access restricted).
- Hart, S. G. & Staveland, L. E. (1988). Development of NASA-TLX (Task Load Index): Results of empirical and theoretical research. In P. A. Hancock and N. Meshkati (Eds.), Human Mental Workload (pp. 139-183). Elsevier Science Publishers B. V. (North Holland).
- Raufaste, E., Terrier, P., Grabisch M., Lang, J. & Prade, H. (2001). Etude expérimentale de l'applicabilité de modèles d'agrégation flous à l'étude de la charge mentale. In Journées d'études en Psychologie Ergonomique (pp. 171-176), EPIQUE 2001, Nantes, 29-30 octobre 2001. PDF
- Mayer Richard E. & Roxana Moreno (2003). Nine Ways to Reduce Cognitive Load in Multimedia Learning, Educational Psychologist 2003 38:1, 43-52
- Pass, Fred; Juhani E. Tuovinen, Huib Tabbers, Pascal W. M. Van Gerven, Cognitive Load Measurement as a Means to Advance Cognitive Load Theory, Educational Psychologist 2003 38:1, 63-71 Abstract/PDF (Access restricted)
- Heeb, Hanspeter (2001), Roboworld Overcoming the Problem of Cognitive Load in Object-Oriented Programming by Microworlds, Mémoire DESS en Sciences et Technologies de l'Apprentisssage et de la Formation, TECFa, Université de Genève. Zip file
- Pass, Fred; Alexander Renkl and John Sweller (2003). Cognitive Load Theory and Instructional Design: Recent Developments, Educational Psychologist, 38(1), 1-4.
- Sweller, J. (1988). Cognitive load during problem solving : Effects on learning. Cognitive Science, 12, 257-285.
- Sweller, J. (1994). Cognitive load theory, learning difficulty and instructional design. Learning and Instruction, 4 , 295-312.
- Sweller, J. (2003). Evolution of human cognitive architecture. In B. H. Ross (Ed.), The psychology of learning and motivation (Vol. 43, pp. 215-266). New-York: Academic Press.
- Sweller, J., Chandler, P., Tierney, J., & Cooper, M. (1990). Cognitive load as a factor in the structuring of technical material. Journal of Experimental Psychology: General, 119, 176-192.
- Sweller, J., van Merrienboer, J. J. G., & Paas, F. G. W. C. (1998). Cognitive architecture and instructional design. Educational Psychology Review, 10(3), 251-296.