HOUSTON, March 9 (UPI) -- U.S. researchers say a study has confirmed the human brain has three concentric layers of working memory where it stores and processes short-term memory items.
Scientists from Rice University and Georgia Institute of Technology say the study could settle a long debate about how many layers there are and what the function of each is, a Rice release reported Wednesday.
The researchers said short-term memory operates in three areas: a core focusing on one active memory item; a surrounding layer holding at least three more active items; and a wider region containing passive items that have been tagged for later retrieval or "put on the back burner."
However, they say, the core region, called the focus of attention, has three roles, not two as proposed by previous researchers.
First, it directs attention to the correct item; second, it retrieves the item; and third, if necessary, it updates it.
The researchers also discovered that practice, or repetition of a particular memory task, can enhance the focus of attention to store four items in the core.
"When you do the same sequence over and over again, your memory can be partially automated so you have the ability to do another task concurrently," Rice psychology Professor Chandramallika Basak said.
For example, he said, 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.
"Predictability can free up resources so a person can effectively multitask," he said.
However, that same secondary task -- the grocery list -- becomes more difficult when driving to a different grocery store using an unfamiliar route, he said.