Working memory in children: What you need to know

© 2019 Gwen Dewar, Ph.D., all rights reserved

young boy holding chin in contemplation, image by Personal Creations (flickr)

Working memory is often likened to the RAM in a computer. The more you have, the faster you can process data. But young children have smaller working memory capacities than adults. And some kids face special challenges. What's at stake? How can you tell if a child is struggling? What can we do to help kids develop stronger working memory skills? Here's an evidence-based guide.

What is working memory, and why is it important?

Working memory, also known as WM, is a bundle of mechanisms that allows us to maintain a train of thought.

It's what we use to plan and carry out an action -- the mental workspace where we manipulate information, crunch numbers, and see with our "mind's eye" (Cowan 2010; Miller et al 1960).

  • Can you add together 23 and 69 in your head?
  • Remember a list of grocery store items without writing them down?
  • Recall the seating arrangements of a dinner party after a brief glimpse at the table?

These tasks tap working memory, and whether or not you succeed depends on your working memory capacity, or WMC.

People with larger capacities can juggle more information at once. This helps them process information more quickly, and the benefits are well-documented. People with higher-than-average working memory capacity are more likely to excel in the classroom.

For example, when researchers have tracked the development of primary school children, they've found that early gains in working memory predict later achievement in mathematics (Li and Geary 2013; Li and Geary 2017).

Working memory is also predictive of language skills, like the ability to keep track of the ideas presented in a long or complex sentence  (Zhou et al 2017).

On the flip side, individuals with poor working memory skills at a disadvantage. They are more likely to struggle with mathematics and reading. They may also struggle with following spoken directions. There is too much to juggle, and they lose track of what they are supposed to do.

But what's normal? Doesn't working memory develop as a child gets older?

Yes. When researchers have administered the same WM tests across age, they've found evidence for steady improvement, with adults performing almost twice as well as young children (Gatherole et al 2004; Gatherole and Alloway 2007).

For example, in WM tasks dependent on tracking items in a briefly-presented visual array, adults remember approximately 3 or 4 objects (Cowan 2016). Five-year-olds recall only half as many (Riggs et al 2006).

So how can we tell if a child has a low working memory capacity for his or her age?

Researchers estimate that 10-15% of school age children are struggling with low working memory capacity (Holmes et al 2009; Fried et al 2016). How can we identify these kids?

A professional diagnosis depends on administering special tests, like the Comprehensive Assessment Battery for Children - Working Memory (CABC-WM), or the Automated Working Memory Assessment (which you can read about here).

But you can also look for everyday signs. According to Susan Gatherole and Tracey Alloway (2007), kids with working memory difficulties typically

  • have normal social relationships with peers;
  • are reserved during group activities in the classroom, and sometimes fail to answer direct questions;
  • find it difficult to follow instructions;
  • lose track during complicated tasks, and may eventually abandon these tasks;
  • make place-keeping errors (skipping or repeating steps);
  • show incomplete recall;
  • appear to be easily distracted, inattentive, or "zoned out"; and
  • have trouble with activities that require both storage (remembering) and processing (manipulating information).

Do poor working memory skills mean that a child isn't smart? Do strong working memory skills mean that a child is highly intelligent?

No.

Working memory affects how we learn. It helps us stay focused when there are distractions. It can have an impact on how well we perform on tests, including achievement tests and IQ tests. But we can’t equate WM with overall intelligence. 

For instance, take "fluid intelligence" -- what psychologists define as "the ability to reason through and solve novel problems" (Shipstead et al 2016).

Fluid intelligence doesn't just demand that we keep relevant information in mind. It also requires that we discard -- stop thinking about -- information that is irrelevant. We need to forget outdated ideas in order to make room for new ones (Shipstead et al 2016). 

Thus, it isn't so much the size of mental notepad that matters, but whether we are filling that notepad with the most promising information. Merely having a larger WM capacity doesn't necessarily make you smarter.

Then there is the evidence from IQ tests: Working memory capacity doesn't always correlate with IQ.

Some kids perform well on IQ tests and yet have relatively mediocre WM skills (Alloway and Alloway 2010). How is this possible? Tests like the Wechsler Intelligence Scale for Children (WISC) have distinct subtests. Some specifically target working memory. Others don’t.

In addition, there are components of intelligence that go largely unmeasured by IQ tests, and don't correlate with working memory capacity.

One example is rationality and logic. It's a reflective mode of thought that IQ tests ignore. But it's essential for making smart decisions, and it's not clear that working memory capacity has much of an impact. In recent experiments, people with higher WMCs were just as likely as other folks to experience biased, faulty reasoning (Robinson and Unsworth 2017).

Finally, it's important to remember that working memory isn't a single, unitary system. There are different types of WM, and each type is associated with different kinds of thinking.

For instance, verbal working memory predicts better performance on verbal tasks, but not spatial tasks.

Spatial working memory (tracking where items are located) is linked with better spatial skills, but not superior verbal ability (Shah and Miyaki 1996).

A third type of WM -- being able to remember visual imagery -- is linked with its own special advantages (Fanari et al 2019). 

And there may be other, distinct types of working memory, like the ability to keep track of sequences (e.g., the order in which items appear on a list). "Series order" working memory is linked with better arithmetic performance (Attout and Majerus 2018; Carpenter et al 2018).

So differences in cognitive performance are related to differences in working memory capacity. But they effects can be pretty specific. For instance, a child with dyscalculia (a mathematical learning disability) might test normally in verbal WM, but lag behind in "series order" WM (Attout and Majerus 2015). 

What about other learning disabilities and developmental disorders?

Working memory problems can make it more difficult for young children learning to read. And deficits in verbal working memory have been linked with reading comprehension problems in older children (Peng et al 2018). 

Kids with autism are also more likely to experience working memory problems, with deficits in spatial WM being more common than deficits in verbal working memory (Wang et al 2017).

Children with attention deficit hyperactivity disorder (ADHD) are more likely than normally-developing kids to suffer from impairments of verbal working memory (Ramos et al 2019; Kennedy et al 2019).

What can we do to boost working memory skills? Can we improve working memory by playing simple memory games?

Yes, but not necessarily in a way that is helpful for school achievement.

You might have heard of computer-based memory games that are supposed to enhance WM, or even IQ. Do they actually work? It depends on what you mean by "work."

For example, consider the computer-based training program developed by Cogmed.

In one study, researchers identified kids with low WMC, and assigned these children to play a series of computer games designed to challenge their WM skills (Holmes et al 2009). Some of these games  included:

  • Hearing a series of letters read aloud ("G, W, Q, T, F…") and repeating them back.
  • Watching a battery of lamps light up, one at a time, and then recalling the correct sequence by clicking the correct locations with a computer mouse.
  • Hearing and watching a sequence of numbers while they are spoken aloud and flashed on a keypad. After each sequence, the student is asked to reproduce the sequence in reverse order by hitting the correct digits on the keypad.

For children in a control group, the difficulty level of these tasks remained easy throughout the study. But for kids in the treatment group, the program was adaptive, i.e., a student was given progressively more difficult tasks as his or her performance improved.

After about 6 weeks of training, researchers re-tested the students' working memory skills, and the results were pretty dramatic. While both groups improved, the kids in the adaptive program did much better. Their average gains were 3 to 4 times higher than those of kids in the control group.

But there was a crucial catch: Improvements were found only on tests that closely resembled the training games. And that has been the pattern in other studies.

Training helps people get better at the specific tasks for which they are trained. But it doesn't seem to help people perform better in other areas -- like reading or mathematics.

"Far transfer effects" haven't panned out -- not in the largest,  best-designed, most carefully controlled studies conducted to date (Sala and Gobet 2017; Melby-Lervåg et al 2016; Shiphead et al 2012).

So if you are interested in improving a child's performance in working memory games, then this type of training is worthwhile. And perhaps someday we'll find out these games deliver long-term benefits that researchers haven't yet been able to detect.

But if you're goal is to help your child in the classroom, it probably makes more sense to target the tasks that are giving him or her trouble.

If a child struggles with mathematics, seek out special training in the relevant mathematical skills -- like counting, number sense, or basic arithmetic calculations (Kyttälä et al 2015).

If a child is having trouble with reading, look for programs that designed for kids who need to build literacy skills (Melby-Lervåg et al 2016).

What else can we do?

As Susan Gathercole and Tracey Alloway note, we can help children compensate for WM limitations in a variety of ways. For example:

  • We can break down tasks into smaller subroutines, so kids can tackle just one component at a time.
  • We can adjust the way we communicate, so we don't introduce too much material at once, and provide children with regular reminders of what they need to do next.
  • We can ask kids to repeat back new information, and help them connect it with what they already know.
  • We can prompt kids with regular reminders of what to do next, and encourage them to ask questions when they feel lost.
  • We can teach them how to create and use their own memory aids -- like taking notes.

And research suggests other tactics too. To get the most from your WMC, you need to understand how it functions. What disrupts WM? What tricks allow people to pack more data in the mental workspace?

For more information, check out these evidence-based tips for improving working memory performance.


References: Working memory in children

Alderson RM, Kasper LJ, Patros CH, Hudec KL, Tarle SJ, Lea SE. 2015. Working memory deficits in boys with attention deficit/hyperactivity disorder (ADHD): An examination of orthographic coding and episodic buffer processes. Child Neuropsychol. 21(4):509-30.

Alloway TP and Alloway RG. 2010. Investigating the predictive roles of working memory and IQ in academic attainment. Journal of Experimental Child Psychology 106(1): 20-29.

Alloway TP. 2007. Automated working memory assessment. Oxford: Harcourt.

Attout L and Majerus S. 2018. Serial order working memory and numerical ordinal processing share common processes and predict arithmetic abilities. Br J Dev Psychol. 36(2):285-298.

Attout L and Majerus S. 2015. Working memory deficits in developmental dyscalculia: The importance of serial order. Child Neuropsychol. 21(4):432-50.

Carpenter AF, Baud-Bovy G, Georgopoulos AP, Pellizzer G. 2018. Encoding of Serial Order in Working Memory: Neuronal Activity in Motor, Premotor, and Prefrontal Cortex during a Memory Scanning Task. J Neurosci. 38(21):4912-4933.

Cowan N. 2016. Working Memory Maturation: Can We Get at the Essence of Cognitive Growth? Perspect Psychol Sci. 11(2):239-64.

Cowan N. 2010. The Magical Mystery Four: How is Working Memory Capacity Limited, and Why? Curr Dir Psychol Sci. 19(1):51-57.

Cowan N. 2001.The magical number 4 in short-term memory: a reconsideration of mental storage capacity. Behav Brain Sci. 24(1):87-114; discussion 114-85.

Fanari R, Meloni C, Massidda D. 2019. Visual and Spatial Working Memory Abilities Predict Early Math Skills: A Longitudinal Study. Front Psychol. 10:2460.

Fried R, Chan J, Feinberg L, Pope A, Woodworth KY, Faraone SV, Biederman J. 2016. Clinical correlates of working memory deficits in youth with and without ADHD: A controlled study. J Clin Exp Neuropsychol.38(5):487-96.

Gathercole SE, Pickering SJ, Ambridge B, Wearing H. 2004. The structure of working memory from 4 to 15 years of age. Dev Psychol. 40(2):177-90.

Gathercole SE and Alloway TP. 2007. Understanding working memory. London: Harcourt.

Holmes J, Gathercole SE, and Dunning DL. 2009. Adaptive training leads to sustained enhancement of poor working memory in children. Dev Sci. 12(4):F9-15.

Jaeggi, S. M., Buschkuehl, M., Jonides, J., & Perrig, W. J. (2008). Improving Fluid Intelligence With Training on Working Memory. Proceedings of the National Academy of Sciences of the United States of America, 105(19), 6829-6833.

Kennedy RJ, Quinlan DM, Brown TE. 2019. Comparison of Two Measures of Working Memory Impairments in 220 Adolescents and Adults With ADHD. J Atten Disord. 23(14):1838-1843.

Kuhn JT, Ise E, Raddatz J, Schwenk C, Dobel C. 2016. Basic numerical processing, calculation, and working memory in children with dyscalculia and/or ADHD symptoms. Z Kinder Jugendpsychiatr Psychother. 44(5):365-375.

Kyttälä M, Kanerva K, Kroesbergen E.2015. Training counting skills and working memory in preschool. Scand J Psychol. 56(4):363-70.

Li Y  and Geary DC. 2013. Developmental gains in visuospatial memory predict gains in mathematics achievement. PLoS One. 8(7):e70160.

Li Y and Geary DC. 2017. Children's visuospatial memory predicts mathematics achievement through early adolescence. PLoS One. 13;12(2):e0172046.

Melby-Lervåg M, Redick TS, Hulme C. 2016. Working Memory Training Does Not Improve Performance on Measures of Intelligence or Other Measures of "Far Transfer": Evidence From a Meta-Analytic Review. Perspect Psychol Sci.11(4):512-34.

Miller GA, Galanter E, Pribram KH. 1960. Plans and the structure of behavior. New York: Holt, Rinehart and Winston.

Peng P, Barnes M, Wang C, Wang W, Li S, Swanson HL, Dardick W, Tao S. A meta-analysis on the relation between reading and working memory. Psychol Bull. 144(1):48-76.

Ramos AA, Hamdan AC, Machado L. 2019. A meta-analysis on verbal working memory in children and adolescents with ADHD. Clin Neuropsychol. 22:1-26.

Riggs KJ, McTaggart J, Simpson A, Freeman RP. 2006. Changes in the capacity of visual working memory in 5- to 10-year-olds. J Exp Child Psychol. 295(1):18-26.

Robison MK and Unsworth N. 2017. Individual differences in working memory capacity and resistance to belief bias in syllogistic reasoning. Q J Exp Psychol (Hove). 70(8):1471-1484.

Sala G and Gobet F. 2017. Working memory training in typically developing children: A meta-analysis of the available evidence. Dev Psychol. 53(4):671-685.

Shah P and Miyake A. 1996. The separability of working memory resources for spatial thinking and language processing: an individual differences approach. J Exp Psychol Gen. 125(1):4-27.

Shipstead Z, Harrison TL, Engle RW. 2016. Working Memory Capacity and Fluid Intelligence: Maintenance and Disengagement. Perspect Psychol Sci. 11(6):771-799.

Shipstead Z, Hicks KL, and Engle RW. 2012. Cogmed working memory training: Does the evidence support the claims? Journal of Applied Research in Memory and Cognition 1 (3): 185–193.

Stanovich KE. 2009. What intelligence tests miss: The psychology of rational thought. Yale University Press.

Wang Y, Zhang YB, Liu LL, Cui JF, Wang J, Shum DH, van Amelsvoort T, Chan RC.A Meta-Analysis of Working Memory Impairments in Autism Spectrum Disorders. Neuropsychol Rev. 27(1):46-61.

Zhou H, Rossi S, Chen B. 2017.Effects of Working Memory Capacity and Tasks in Processing L2 Complex Sentence: Evidence from Chinese-English Bilinguals. Front Psychol. 20(8):595.

Content last modified 12/2019

Title image of contemplative boy by Personal Creations / flickr

Image of toddler with mother by Bill Strain / flickr

image of children on iPads by Lexie Flickinger / flickr