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Brain has working memory times 3

RICE (US) — The human brain is able to multitask successfully in part because of three layers of memory that store information on a need to know basis.

Short-term memory is made up of a core focusing on one active item, a surrounding area holding at least three more active items, and a wider region containing passive items that have been put on the back burner for later retrieval.

Further, the brain’s core region, called the focus of attention, has three roles that directs attention to the correct item, which is affected by predictability of input pattern. The brain then retrieves the item and subsequently, when needed, updates it.

Details of a new study are published in the Journal of Cognitive Psychology.

Chandramallika Basak, professor of psychology at Rice University and Paul Verhaeghen, associate professor of psychology at Georgia Tech, used simple memory tasks involving colors and shapes on a computer screen to determine the three distinct layers of memory and determined the roles of attention focus by exploring the process of switching items in and out of the focus of attention.

The study of 49 participants across two experiments, shows that when no pattern exists, all response time was increased by an average of 240 milliseconds per item as more items are stored, implying that when there is no pattern, the area outside the focus has to be searched even before the item can be retrieved.

When participants were given 10 hours of practice in a memory task with a predictable pattern, all could enhance the focus of attention to store four items in the focus core.

But again, the focus does not expand when the memory task has no pattern.

“Predictability can free up resources so a person can effectively multitask,” says Basak, lead author of the study.

“When you do the same sequence over and over again, your memory can be partially automatized so you have the ability to do another task concurrently.”

This comes naturally, Basak says. For instance, as you drive the usual route to your regular grocery store, you might also be thinking about what to fix for dinner and making a grocery list.

That secondary task—the grocery list—becomes more of a challenge when driving to a different grocery store using an unfamiliar route.

Further, the first two regions are protected by a firewall of sorts from the third that contains the passive items—the number of passive items has no bearing on response time or accuracy in recalling active items.

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