Working memory: lightening the cognitive load for pupils

This article was written for SecEd magazine and first published in June 2019.  You can read the original version on the SecEd website here.  

You can access the full archive of my columns for SecEd here

I moved house last month. Those who claim it’s one of the most stressful things you can do in life are not wrong. The solicitor’s bill alone was enough to send my blood pressure through the roof. But, contrary to popular opinion, the stress does not dissipate the moment the removals van pulls off the drive.

Coming to terms with life in a strange house is also challenging. Take, for example, cooking. In our old home, I would dance around the kitchen with balletic grace retrieving pots and pans, utensils, and ingredients from their various storage places. But now, in our new house, I struggle to find even the necessities to make the most basic of meals. (Cheese on toast has become a regular fixture on the family menu).

Even if I could find what I needed, I’d struggle because the cooker has a very tenuous relationship with both heat and time – gas mark 8 is the new gas mark 6 and what should take twenty minutes now takes in excess of two hours, or sometimes no more than two minutes – there’s no rhyme nor reason to it; whenever I place a chicken in the oven I do so with a silent prayer, not knowing if it will emerge clucking or cremated.

We may as well have moved to Mars. They’d be better WiFi for starters.

But why should moving house be so tough and what on Earth (or indeed Mars) has this got to do with teaching? Allow me to explain…

The cognitive science

The working memory (sometimes called the short-term memory) is the place where we actively process information; it is where we think and do.

In order to learn something new, we need first to wrestle with it in working memory then encode it into long-term memory from where we can retrieve it and use it later. But working memory is very small.

Miller’s Law (Miller, 1956) posits that working memory is limited to seven plus or minus two unique concepts. In other words, we can only process – actively think about – between five and nine unique concepts at once. That rather begs the question: what is a unique concept? Well, it depends…

I define a “unique concept” as something which carries a single unit of meaning, so it could be a letter, a word or a sentence depending on what meaning we attach to it.

For example, the 20 letters – H T N O M T S A L E S U O H D E V O M I – contain no collective meaning for us and therefore take up 20 spaces in working memory, which is beyond our capacity. If we tried to learn these letters in isolation, we would likely fail because we would overpower working memory – what is called “cognitive overload”.

However, if we combined those letters into words – such as LAST, MOVED, MONTH, I and HOUSE – then those 20 concepts could be chunked into five unique concepts – five units of meaning which we could easily hold in working memory. But, if we then combined those five words into a single sentence – such as the first sentence of this article (I MOVED HOUSE LAST MONTH) then we could chunk the information even further into just one unique concept and hold this plus much more besides in our working memory. We call this “chunking” schema – it is a way of forging connections between the working memory and the long-term memory.

Anyway, I digress – although this point will prove helpful later so hold onto it, if you can…

The working memory war

Working memory, then, is small and we cannot make it any bigger. Whenever we think about or do anything, we use working memory and it is not just the information we are thinking about that takes up space. In fact, there is a constant battle being fought in our working memories for its limited capacity.

Every task – whether it is mental or physical – requires us to balance three forms of cognitive load: intrinsic load, germane load and extraneous load.

Intrinsic load is the amount of mental activity involved in performing a task to actively think about what we are doing.

Germane load is the amount of mental effort involved in trying to understand the task – if the task is new or unfamiliar, we have to use some working memory capacity to try make sense of it and decide how to tackle it.

Extraneous load is concerned with understanding the immediate environment within which we are trying to perform a task. Disorganised or unfamiliar contexts contribute extraneous load to a task. For example, if I am trying to read a challenging book I will fare better if I am in a quiet, comfortable room devoid of distractions than if I am on a noisy train.

And that explains why moving house is stressful: performing everyday tasks is made harder because the extraneous load is much greater when we perform them in a strange new place.

Classroom consistency

And it is the same for our pupils. When they are learning in our classrooms, there is a war being waged in their working memories, too. If we present them with unfamiliar tasks which contain entirely new information and which is presented in a new way, then we are placing unsustainable demands on their working memories and learning is likely to fail.

We cannot – and would not want to – eliminate all the cognitive load because if everything was too familiar and undemanding (in other words, too easy) then pupils would not have to think at all and therefore would not encode anything into long-term memory. No, work has got to be hard so that pupils are made to actively think about it. But we want the focus of their hard work in lessons to be on curriculum content, not on having to contend with a distracting instructional style or learning environment. Let me give you an example…

If I wanted pupils to learn some key facts about Shakespeare’s life in order to aid their analysis of the authorial context of one of his sonnets, I could ask them to conduct some independent internet research. But there is a good chance, if they are not skilled and practised internet researchers, that most if not all of their working memory capacity will be dedicated to the “how?” not the “what?”.

In other words, they would have to think so hard about how to conduct research (where to go, what to type in, how to sift through the search results and discern the trustworthy from the tosh, how to skim and scan for key facts, how to present their findings, and so on…) that they would not be able to actively attend to the facts about Shakespeare’s life. And because they had not actively thought about those facts during their research they are unlikely to encode them into long-term memory.

To help to overcome these challenges and mitigate these risks, we need to provide greater consistency in the way we teach our pupils and that, in turn, means we need to plan together.

Yes, this does mean less teacher autonomy in the sense of teachers working in isolation, but it also means more collective autonomy in the sense of teachers working together to ensure pupils learn more and achieve more.

Collective autonomy

What might this look like in practice? Let me give you an example…

When teaching persuasive writing in English, it helps if we provide pupils with schema to aide their retrieval of information from long-term memory. For example, in an exam we want our pupils to be able to remember which rhetorical devices to use in order to write persuasively and so, to help, we might teach them a mnemonic like “AFOREST” which in my version stands for: “Amazing opening, Facts, Opinions, Rhetorical questions, Emotive language, Statistics, Thought-providing ending.”

Remember earlier when I said that working memory is small but we can cheat its limitations by chunking information into meaningful units such as words and sentences? Well, in the example above, pupils can do this by simply holding one word – AFOREST – in working memory which sparks a connection to more detailed information stowed in long-term memory. By chunking in this way, pupils can free up more working memory to think about the actual task in hand, i.e. the exam question and the topic on which they need to persuade.

However, if every teacher in an English department taught a different mnemonic or all used AFOREST but had different definitions for it (for example, one teacher has the A stand for “Alliteration” rather than “Amazing opening”) or they all used the same word with the same definitions, but presented it in an entirely different format (different font, different background image, etc) then although the mnemonic will go some way to helping pupils cheat their working memories, they would still have to dedicate more working memory capacity to processing it and understanding it whenever they moved from one teacher to another.

The example I have provided above is small and simplistic for the purposes of easy illustration but often teachers working in blissful isolation create all sorts of roadblocks for their pupils’ cognition without thinking about it or meaning to.

We teachers often use a different language (see “connective” versus “conjunction”) or methods (see long division); we have different aide memoirs in our classrooms and/or in different locations of our rooms; and – perhaps most unhelpful of all – we have differing sets of expectations and different systems for (or ways of applying) rewards and sanctions.

Every time teachers do things differently to one another, they require pupils to use some of their working memory to process the instructional context and learning environment. In short, the extraneous load gets bigger when teachers are left to their own devices. And that leaves less space for the intrinsic load and therefore means pupils perform less well.

For this reason, and spurred by my recent house move, I have come to recognise the importance of collective rather than individual autonomy, and now appreciate the need for greater consistency across a department and school. This means that teachers need to be afforded the time to get together as a subject team for curriculum planning and the creation of pooled resources.

And the added benefit of this approach is that teachers’ workloads will be reduced. Rather than every member of a department planning their own schemes of work and creating their own resources, the team do this collectively – and a scheme of work shared is a scheme of work halved, after all.

 

Follow me on Twitter: @mj_bromley

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