How can we plan learning and pitch it appropriately? We must strike a balance between sufficient and excessive challenge; we need some way to decide which objectives and activities to use.
Cognitive load theory offers a powerful way to view learning, select activities and plan objectives. This post describes the theory and suggests how it could be applied to planning lessons. The terms used are subject to heated debate, so if anything is unclear, or you have suggestions as to how this could be improved, please don’t hesitate to let me know.
What is cognitive load theory?
Cognitive load theory theory focuses on learning as the creation of schemas: organised structures of knowledge in long-term memory. Ideas reach long-term memory having been held in working memory: what we are conscious of at a given moment. Working memory can only cope with a limited cognitive load: we can retain a handful of isolated facts (a few numbers, for example), or process two or three ideas (Sweller, van Merriënboer and Paas, 1998; Cowan, 1999). Therefore, the load placed upon working memory – what students are thinking about – is crucial for learning.
An early study divided students into two groups; they approached the same trigonometry problems with different goals:
- Group A were given a specific goal (find the length of a particular line)
- Group B were not given a specific goal (find the length of any lines you can)
They were solving identical problems, but students in Group A endured greater cognitive load, because they had to keep in mind what they were trying to find, what they had already found and what they needed to find next. Students in Group B remembered more about the problems – they learned more; whereas for students in Group A:
The cognitive-processing capacity needed to handle this information may be of such a magnitude as to leave little for schema acquisition, even if the problem is solved (Sweller, 1988: p.261).”
Students can concentrate on solving problems, they can concentrate on tasks which contribute to their long-term memory, but if the task is challenging for them, they are unlikely to manage both. Working memory limitations restrict how much of an experience reaches long-term memory: designing teaching “which flouts or merely ignores working memory limitations inevitably is deficient (Sweller, van Merriënboer and Paas, 1998, p.253).”
Three forms of cognitive load were proposed by Sweller, van Merriënboer and Paas (1998); they offer a helpful frame for planning:
Intrinsic cognitive load
Intrinsic cognitive load is the challenge of learning complicated ideas. Individual facts can be learned in isolation, so have low intrinsic cognitive load:
- Students can learn the meaning of ‘Je’ without knowing the word ‘aime’ in French.
- They can learn that Fe is iron without having to remember that Cu is Copper.
Some learning has high intrinsic cognitive load however:
- Students must consider the relationship between each word in a sentence to ensure it is grammatically correct.
- Explaining a chemical reaction requires understanding the interaction between different elements.
Whether learning has high intrinsic cognitive load reflects a student’s existing knowledge, not an absolute standard: a competent French speaker may face low intrinsic cognitive load when considering the words in a simple sentence, but need to think more carefully when using the subjunctive tense.
It is possible to break down content with high intrinsic cognitive load (van Merriënboer and Sweller, 2005), but our priority is selecting the intrinsic cognitive load on which the lesson will focus carefully.
Extraneous cognitive load
Extraneous cognitive load is the distraction caused by tasks which occupy working memory but do not contribute to the formation of long-term memories. This includes:
- Splitting attention: asking students to refer to two sources of information simultaneously: we can avoid this by ensuring information, such as labels, is where it will be needed.
- Redundancy: information which adds nothing detracts from learning: we can avoid this by removing irrelevant and distracting labels and text.
- Expertise reversal: support which helps novices, like model answers, can hinder experts; we can monitor students’ success closely and reduce support as students become more skilled.
We can also also use the modality effect: describing an image verbally, for example, talking through a diagram, effectively increases students’ working memory.
Germane cognitive load
Germane cognitive load is additional cognitive load which contributes to the formation of long-term memories. It can be created by tasks which depress student performance initially but help retention, including spacing learning over time (Pashler et al., 2007) and varying practice (for example, varying the types of mathematical questions students are answering in a lesson (Soderstrom and Bjork, 2015)). (For a fuller discussion, see this post).
The limits of cognitive load theory
There are limits to what cognitive load theory offers. The research findings have been tested in a handful of topics, subjects and lessons. While they seem robust, and work to extend them is ongoing, there are limited examples which have been tested in classrooms, so we need to apply the ideas carefully. Varying practice will work in a grammar lesson, but in a lesson on literature it may prove unhelpfully confusing: instead, we may simply add a retrieval question to our exit tickets to space learning (Pashler et al., 2007). Approaches which support learning, like varying practice, can prove disorienting and hence unpopular with students (Brown, Roediger and McDaniel, 2014, p.54): we may wish to explain the rationale for our choices to students and perhaps even occasionally choose less efficient ways of teaching to maintain student enthusiasm. Cognitive load theory offers useful ideas, not perfect answers: using it requires tailoring the principles to our students and lessons: cognitive load theory.
We can plan for cognitive load by:
- Choosing intrinsic cognitive load carefully
- Cutting extraneous cognitive load: remove unproductive distractions
- Increasing germane cognitive load judiciously: adding variation
And recognising the limits of the existing research, as well as its promise.
What should I read next?
The importance of knowledge: some initial thoughts on constructing schemas
More on distinguishing between learning and performance (and what this means for formative assessment).
A checklist for lesson planning: bit dated but maybe still useful.
Cowan, N. (1999). An embedded-processes model of working memory. In Miyake, A. and Shah, P. eds. Models of working memory: Mechanisms of active maintenance and executive control New York, NY, US: Cambridge University Press, pp. 62-101.
Pashler, H., Bain, P., Bottge, B., Graesser, A., Koedinger, K., McDaniel, M., and Metcalfe, J. (2007) Organizing Instruction and Study to Improve Student Learning (NCER 2007-2004). Washington, DC: National Center for Education Research, Institute of Education Sciences, U.S. Department of Education.