Ever pulled your car over to ask a passing pedestrian for directions? If so, you may have an idea of how unreliable working memory can be. “Continue down the road, take the second left, and then at the third set of lights turn right and then left.”

Some people are lucky. They will hold those instructions in their working memory, put the car in gear and arrive in plenty of time without getting lost.

Others are less fortunate. They will have forgotten at least half of the instructions by the time they drive off, and in the time it takes to decide to stop to ask for directions again, they will have forgotten even more.

Now imagine those instructions are for a task and they come from a teacher in a busy classroom. And imagine a large proportion of the pupils are in that second group of forgetful motorists. If every child is to succeed in that particular class, working memory is something the teacher needs to understand.

Susan Gathercole is a psychologist, programme leader for the Memory and Perception Group at the University of Cambridge, and an expert on the cognitive mechanisms of short-term and working memory. She defines working memory as “the most temporary of all our memory systems”.

“It is about holding information in mind and keeping it in mind until you no longer need it,” she explains.

Enormous variation

The amount we can hold in our working memory and how long we can hold it for varies enormously from person to person. Gathercole has studied those schoolchildren with low working-memory capacity very closely, and frequently works with teachers to help them to better understand how it might manifest in the classroom.

“In one study, we had a look at the range of working-memory capacities within a classroom group of eight-year-olds, and we found that the bottom 10 per cent had the working-memory capability of the average five-year-old but, in the same class, the top 10 per cent had adult working-memory capacities,” she says.

Studies show that, typically, the amount of information a child can hold in their head for a short period will increase steadily from age 5 to 12 - perhaps more than doubling in that period - followed by further gradual improvement up to mid-adolescence, at about 15 years of age, when adult levels of capacity are reached.

“That is what happens, on average, across age but there are very wide individual differences,” Gathercole says, “and we know those differences are quite stable - so it is not as if you have bad working memory one year and a great working memory the next.”

There are a variety of working memory tests that can help to identify children who may struggle to retain and follow instructions.

“The tasks used to test working memory are actually devised so that people don’t fail them simply because either they are not highly intelligent or there is some sort of code to crack,” she says. “They are actually quite simple tasks.”

A classic working memory check tests “backward digit spans”; pupils are told some numbers and they have to say them backwards - so “four, five, one” becomes “one, five, four”.

“It is only easy when there are three and it starts to get far harder after that,” she says. “What we find is that people with low working memory capacities can’t increase their span with practice, so maybe they will be stuck at a backward digit span of three or four digits while other children might be able to do six or seven.”

What the test does not assess is intelligence. Children with poor working memory have traditionally been labelled as having lower intelligence, but that connection is a myth, says Gathercole.

“The task is essentially the same in both cases [the child remembering the lower number of digits and the child remembering the higher number of digits] - the difference is the number of digits that have to be manipulated, so if you understand the short task, you understand the long task, too. It is not about intellect.”

Although they are categorically not IQ tests, working-memory assessments have become prominent in standardised cognitive-ability testing because they are strong predictors of future academic achievements. In fact, there is significant correlation between strong working-memory capacity and higher academic performance in maths, English and the sciences.

Gathercole recalls one study she worked on in Bristol, where the local authority had pulled together an assessment tool designed to predict how children were going to perform at 11 years old in their key stage 1 Sats.

“We put our working-memory assessments alongside those local authority tests, so as well as the teachers going through the local authority checklist - which was about things like whether a child could write their own name or whether or not they could function socially - we included some simple working-memory assessments.”

The working-memory assessments turned out to be much better predictors of how the children were going to perform.

“This is interesting because working memory tests are designed to be unfamiliar. All the child can do to perform in each task is recall what they have just heard or just seen, they are not based on prior experience or previous successes,” Gathercole explains, making it “a level playing field”.

“This is very different to asking a child if they can write their own name or what three plus three is, which are entirely based on how far they have got before in all the many learning experiences in their life.”

Gathercole and her co-researchers published data on key stages 2 and 3 outcomes, too, and found the same relationship with performance.

Genetic factors

Why working-memory capacity can differ so much is still to be ascertained with any certainty, but the best guess currently is that genetic factors are likely to be at play.

Despite this, many commercial training programmes are available that promise to help develop children’s working memory. Gathercole is highly sceptical about their efficacy. “Whenever we speak to teachers, they ask, ‘Should we be using working memory training?’” she says. “I have been involved for the past 10 years in many an evaluation and I am pretty confident in concluding that, while working-memory training can improve performance on particular tasks...it doesn’t increase ‘free range’ working-memory capacity, which is what the child will need in the classroom.”

This means that while children might learn a trick to help them remember a longer number span, they will not notice a similar improvement in letter recall or in holding information in mind for more abstract, everyday tasks.

“If anyone ever asks me if I would recommend working-memory training, all I say is that, if I had a child with a working-memory problem, I wouldn’t put them through any such training,” she says.

This, then, places much of the responsibility for helping pupils with poor working memory from falling behind in class on the shoulders of the teacher. Does Gathercole have any practical tips for how teachers can identify and cater for pupils who might have this difficulty in their studies?

“There are warning signs for teachers,” she reveals. “Things like children failing to maintain attention in an ongoing activity is a hallmark - they might move on to another task or appear very ‘daydreamy’ and vague. With multiple instructions, a classic sign is that the child can do the first step but then they just don’t know what to do and they have to follow the rest of the class. It is not that the child hasn’t been listening, but they can only remember the first, or the first two items in the sequence.”

For one of her early studies, Gathercole sat in classrooms and wrote down the sequences of instructions that were being given by primary school teachers to their pupils, and often found that the instructions were incredibly lengthy and complex.

“We took some of the instructions and, as part of a project at Durham University, read them out and got university students to repeat them back.

“Quite often, they were just too lengthy even for them to repeat, even though they came from a class for six-year-olds. So, some teachers maybe aren’t quite so good at judging the amount or complexity of information that a child can remember.”

Effective solutions that Gathercole has encountered include the use of diagrams depicting instructions as a reference for students who need it, giving shorter instructions and waiting for the whole class to complete them before moving on, or getting pupils to work in teams.

“In one Year 1 classroom, a teacher had provided audio recorders for each child, and would speak the instructions and record them so the child could listen back to them when they needed and refresh the information that they had lost,” she recalls.

Even learning objectives that can appear relatively straightforward can put a huge strain on working memory.

Ultimately, Gathercole believes awareness is the first step for teachers, and then implementing common-sense approaches to try to reduce the load on pupils. Do that, she believes, and we can ensure that learning opportunities are not missed.

“Each time a child fails to reach the goal of a particular lesson because they have forgotten information is a missed learning opportunity,” she says. “So, avoiding working-memory load in any activity is critical, as is being alert to the signs that a child might not be coping.”

Chris Parr is a freelance writer