Our research commentary prompted quite a bit of discussion on cognitive load theory (CLT) and how we’ve used it. We thought it would be useful to address some of the issues raised.
CLT as part of the learning sciences
CLT forms one part of the evidence we looked at from the learning sciences. Other learning science aspects we used included dual coding and spaced practice.
This evidence from the learning sciences in turn is only one part of the broader evidence base we looked at, which included research from school and teacher effectiveness, research on leadership and research on school effects on physical and mental health. We have not based either our evidence review or the inspection framework on CLT.
However, CLT does form a valuable part of the evidence base on effective practices in education. It is a well-established theory, with over 30 years of research behind it, making it one of the best supported theoretical frameworks in education. That research has been conducted with adult learners, but also with children beginning to learn to read, in upper primary school years and at secondary school.
As with all theories, it has come in for legitimate criticism. This has been around issues such as:
- measurement of cognitive load
- precision of definitions
- extent and motivation for changes to the theory over time
Criticism does not invalidate the theory, which as mentioned above is supported by a large body of research. It does, however, show that we would be misguided if we relied solely on CLT as the basis for our evidence. We have therefore steered clear of doing this.
What CLT says and implications for classroom practice
CLT is about the architecture of memory and the brain and, in particular, the capacity of the short-term memory to process information.
Long-term memory consists of a range of schemata. These are complex structures that link knowledge, create meaning and allow skills to be performed. They are built up over time.
Learning is about developing those schemata through acquiring knowledge and making connections with different schemata. However, before information enters long-term memory, it needs to be processed by the short-term or working memory. This has limited capacity. It is not able to retain knowledge or develop schemata if it is overloaded i.e. if we are given too many things to think about at once.
However, CLT is not about minimising cognitive load. It is about not exceeding the cognitive load that people can deal with. Deep learning requires cognitive load (learning is hard!), but it must be relevant to the task and help rather than hinder learning.
CLT has been interpreted by some as leading to a narrow conception of classroom practice. However, what CLT actually suggests is that teachers should consider what cognitive load they are asking from learners and whether that is appropriate at that particular stage of learning a topic. It is important for teachers to understand the distinction between novice and expert here.
When teaching, we need to take account of expertise reversal effects (these are the interactions between levels of learners’ prior knowledge and the effectiveness of different teaching techniques). Experts possess more detailed and complex schemata than novice learners and therefore it is easier for them to perform complex tasks in their working memory. Novices need more help to gradually build their schemata on a topic and to link it to others. Expertise here is not primarily about age but about the knowledge the learner already has about a particular topic.
This approach suggests teaching activities that do not need too much working memory capacity until learners acquire the knowledge that allows them to spend less time processing content. In many cases, when we are teaching novices, it will make sense to teach in small chunks and ensure that pupils obtain mastery in these before moving onto the next topic. Many teachers have found CLT helpful to their daily practice.
CLT does not dictate a specific teaching method. It does not imply that, for example, teachers should use direct instruction all the time (though of course this is often a useful approach supported by a lot of evidence that does not derive from CLT). Some studies suggest, for example, that collaborative group work can lighten cognitive load in complex tasks. Of course, other evidence suggests that collaborative group work, though potentially highly effective, is hard to do well, which is another reason to draw on multiple sources of evidence!
When it takes effect in September, the education inspection framework will be the most evidence-based, research-informed and tested framework in Ofsted’s 26 year history. Cognitive science is important, but just one part of the wide range of evidence we have drawn upon.
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