Another study on the importance of working memory

Every time I learn something new about our working memory I’m getting more fascinated by it. There are links between how good or bad our working memory works and how much we learn, depression,…

This new study is no exception, although the results are quite logic: differences in an individual’s working memory capacity correlate with the brain’s ability to actively ignore distraction. Geake (2009) compared our working memory with a spam filter, and we all know what happens when spam filters fail… Oh, maybe important to know, the n (= the amount of participants) = 48.

Why is this study significant?

Humans can remember the features of three or four visual objects for short periods of time. Individual differences in this working memory capacity, which accurately predict fluid intelligence and performance in numerous cognitive tasks, have been hypothesized to reflect variations in attentional processes that govern access to the memory system. However, the specific attention mechanism that differentiates high- and low-capacity individuals is unknown. Here, we show that differences in working memory capacity are specifically related to distractor-suppression activity in visual cortex. Our electrophysiological measures reveal that although high-capacity individuals are able to actively suppress distractors, low-capacity individuals cannot suppress them in time to prevent distractors from capturing attention.

I would like to add how important these insights can be for education!

From the press release:

Published this week in the journal PNAS, a research team led by psychology professor John McDonald and doctoral student John Gaspar used EEG technology to determine that while ‘high-capacity’ individuals (those who perform well on memory tasks) are able to suppress distractors, ‘low-capacity’ individuals are unable to suppress them in time to prevent them from grabbing their attention.

“Distraction is a leading cause of injury and death in driving and other high-stakes environments, and has been associated with attentional deficits, so these results have important implications,” says McDonald, who holds a Canada Research Chair in Cognitive Neuroscience.

The study is linked to two previous papers in 2009 and 2014 in which McDonald’s research team showed that when people search the visual world for a particular object, the brain has distinct mechanisms for both locking attention onto relevant information and for suppressing irrelevant information.

The study is the first to relate these specific visual-search mechanisms to memory and show that the suppression mechanism is absent in individuals with low memory capacity.

Abstract of the study:

According to contemporary accounts of visual working memory (vWM), the ability to efficiently filter relevant from irrelevant information contributes to an individual’s overall vWM capacity. Although there is mounting evidence for this hypothesis, very little is known about the precise filtering mechanism responsible for controlling access to vWM and for differentiating low- and high-capacity individuals. Theoretically, the inefficient filtering observed in low-capacity individuals might be specifically linked to problems enhancing relevant items, suppressing irrelevant items, or both. To find out, we recorded neurophysiological activity associated with attentional selection and active suppression during a competitive visual search task. We show that high-capacity individuals actively suppress salient distractors, whereas low-capacity individuals are unable to suppress salient distractors in time to prevent those items from capturing attention. These results demonstrate that individual differences in vWM capacity are associated with the timing of a specific attentional control operation that suppresses processing of salient but irrelevant visual objects and restricts their access to higher stages of visual processing.

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