Neuro Primer: Working Memory Capacity

The brain has three broad types of memory: sensory memory, working memory, and long-term memory. Sensory memory briefly holds unprocessed information retained in the sensory system; working memory temporarily stores and manipulates information to which attention has been applied; and long-term memory encodes information for permanent storage (Stewart, 2010). Working memory is thought to be crucial for learning: information received by sensory memory may only be stored in long-term memory after first being processed by working memory (Baddeley, 2012).

You can think of working memory as a mental sticky note. Imagine hearing someone say something interesting. The information first goes through your auditory system. Then, as you write it down on a sticky note, the information is processed by your working memory. If the information is important, it will be stored in long-term memory.

Examples of working memory include keeping a number in mind while solving an equation in your head, holding onto multiple concepts so you can connect them together, and remembering previous elements of a story before you are done reading it. As working memory allows us to retain multiple pieces of information for short-term processing, it is required for activities such as having a conversation, making decisions, reading, and writing.

Working memory involves the activation of networks across many brain regions. In particular, the prefrontal cortex, a part of the brain closely associated with cognitive control, is thought to play an important role in working memory (Lara & Wallis, 2015; Postle, 2006). Working memory has also been found to activate other frontal and parietal brain regions, including the cingulate and parietal cortices, known for their role in attention and decision-making, as well as subcortical regions such as the midbrain and cerebellum, which contribute to sensory processing and motor coordination (Chai, Abd Hamid & Abdullah, 2018).

A challenging feature of working memory is that it is extremely limited in capacity and duration, which can impact learning. Working memory capacity relates to a range of cognitive skills such as a person’s ability to control their attention, retrieving goal-relevant information, suppressing distractions, constructing mental representations, and solving novel problems (Barrett, Tugade, & Engle, 2004). Not everyone has the same working memory capacity. Individual differences in working memory capacity are to some degree heritable, with 40–65% of the variability in working memory capacity between individuals thought to be related to variations in their genes (Blokland et al., 2011).

Students with lower working memory capacity often struggle in key areas of learning, and identifying working memory impairments can help support neurodiverse classrooms (Alloway & Gathercole, 2006). Differences in working memory capacity may indeed be due to neurodevelopmental conditions, and working memory impairments have been consistently reported in ADHD (Ortega et al., 2020) as well as ASD (Barendse et al., 2013). These working memory impairments impact learning in many ways, especially when it comes to higher-order cognition (Unsworth & Engle, 2005). Learning difficulties associated with working memory impairments include trouble remembering directions, solving arithmetic problems, staying focused, and taking notes (Alloway, 2018).

Unfortunately, we don’t currently understand working memory well enough to train it robustly. A meta-analysis of 87 publications with 145 experimental comparisons concluded that “working memory training programs appear to produce short-term, specific training effects that do not generalize to measures of real-world cognitive skills.” (Melby-Lervåg, Redick & Hulme, 2016). So, where does that leave us?

By investigating novel educational interventions, research may uncover new ways to support learning in students with a working memory impairment. For example, metacognitive scaffolding — instructional guidance that facilitates a student’s thinking and supports their use of learning strategies (An & Cao, 2014) — has been shown to improve cognitive skills such as reading accuracy and listening comprehension (Ahmadi Safa & Motaghi, 2021; Knight & Galletly, 2005).

Much is still unknown about working memory, but it is evident that individual differences in working memory capacity affect cognitive processes that are essential for learning (Cowan, 2014). As working memory training does not yield long-term improvements (Melby-Lervåg, Redick & Hulme, 2016), future research should focus on adapting learning environments so that they reduce the extraneous load on students’ working memory.


Written by Anne-Laure Le Cunff
Illustrated by Melis Cakar
Edited by Lauren Wagner, Chris Gabriel, and James Cole


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Anne-Laure Le Cunff

Anne-Laure Le Cunff is a PhD candidate at the Institute of Psychiatry, Psychology & Neuroscience. Her work uses eye-tracking technology and electroencephalography (EEG) to study how different brains learn differently. She previously earned a MSc in Applied Neuroscience from King’s College London. Her research interests include neurodiversity, psychedelics, and consciousness.