John Sweller, an Australian psychologist, has championed the awareness of working memory for teachers and developed ‘Cognitive Load Theory’. He thinks that awareness of the nature and limitations of working memory make better teachers and learners.
Primary and secondary knowledge
Sweller starts with the evolutionary psychologist Geary’s position on primary and secondary knowledge in The Origin of Mind. We have evolved brains that have intrinsic, biologically primary learning abilities or modules, that allow us to learn some things with ease, such as listening and speaking our native language, facial recognition, folk biology and folk physics. But our plastic frontal areas allow us to override this with our biologically secondary learning, which we have to acquire, such as a second language, reading, writing, maths and so on. It is this secondary knowledge and learning that Sweller focuses on.
Conscious, working memory involves cognitive load, how that working memory deals, or doesn’t deal, with new or novel knowledge. There are two major limitations, capacity and duration. First, it is very limited in capacity as we are only capable of dealing with between two to four elements held at any one time, when trying to solve a problem. Second, we can only hold information for around 20 seconds. However, we also have and rely on long-term memory as our major, larger form of memory, which has no real limits on capacity or duration.
Long-terms memories can be taken back into working memory with relatively little effort, often instantly. This is why it is vital that we get knowledge and skills into long-term memory, so that we can utilise it quickly in working memory. The oft quoted example is our times-tables. We use that form of mental arithmetic often enough to find it useful to get many calculations memorised in long-term memory for instant recall. Once information gets into long term memory, we can then take it back into working memory, transfer it back without effort. So working memory is limited when dealing with novel information. Its effectively unlimited when dealing with processed, stored information that we get from long term memory.
These ideas are critical, because they tells us how to engage in instruction. We engage in instruction in order to get information into long term memory, because once we get that information into long term memory, we're transformed. We become different people. We can do things we couldn't dream of doing otherwise. He argues that an understanding of this is vital if we are to design courses and teach effectively.
When the brain has to deal with multiple elements of information, difficult material, and you have to manipulate or process those different elements, working memory can struggle. It imposes a heavy working load on working memory – that is cognitive load. Sweller argues that this happens all the time when teaching maths, languages even on PowerPoint presentations. Learners take notes because they know, instinctively, what cognitive load means, that they forget things quickly if they are not stored somewhere – either on paper or in long-term memory. Yet instructors continue to make the same mistake of overloading through their own instruction or proxies like PowerPoint.
The teacher, instructional designer and interface designer all have to be aware of how to reduce cognitive load. His advice is that less is more and that redundant, extraneous material has to be removed. With animation, audio and video, things are transient. The stream and flow forward and we can only hold 2-4 elements in working memory for 20 seconds. Without getting that information into long-term memory it will simply be forgotten, like a shooting star your memories literally burn up behind you. Flowing media don’t allow the manipulation and processing necessary for encoding in to long-term memory, so give the illusion of learning.
Intrinsic and extraneous
Intrinsic cognitive load is the load complex material places on working memory. It is subjective, intrinsic and there’s not much you can do about it. Extraneous cognitive load is in the designed instruction and can be redesigned to reduce cognitive load.
Sweller thinks this theory of cognitive load explains why worked examples are superior to problem solving or discovery learning. The worked example is there and you can be shown step by step, whereas with problem solving, you need to manipulate all of the elements before you have understood simpler relationships.
Sweller has had gained a strong following among those who believe that cognitive load theory has much to tell us about practical teaching and learning. He gives clear guidelines on quantifying cognitive load but also on how the theory informs teaching and instructional design. His work is backed up by researchers such as Richard Mayer and others. In sort, less is more.
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