By Lee Clippard and Carl Marzial, University of Southern California
People are more likely to remember information if the pattern of activity in their brain is roughly the same with each review, according to psychologists at USC, the University of Texas at Austin and Beijing Normal University.
The findings, published online Sept. 9 in the journal Science, challenge the long-held belief that humans remember more effectively when they review information in varying contexts—for example, by studying in different places or by mixing types of drills during athletic practice, as described in recent articles in The New York Times and TIME.com.
“The question is how practice makes perfect,” said first author Gui Xue, research assistant professor of psychology at USC College. “If you precisely reactivate the same pattern each time, then you are going to remember better.”
Xue cautioned that the study does not disprove the effect of variable contexts in enhancing memory.
“Restudy under similar context might not always lead to pattern reinstatement, and at the same time, variable contexts might enhance pattern reinstatement. These are both possible, and need to be examined in the future,” he said.
Xue and his collaborators conducted three studies at Beijing Normal University in which subjects were shown different sets of photographs or words multiple times in different orders. Using functional magnetic resonance imaging, the scientists observed subjects’ brain activity while they studied the material. The subjects then were asked to recall or recognize those items between 30 minutes and six hours later.
Based on the decades-old “encoding variability theory,” which suggests people will remember something more effectively if they study it at different times in different contexts, the researchers predicted that the most successful subjects would show more variability in their brain patterns from one review to the next.
Instead, the subjects’ memories were better when their pattern of brain activity was more similar across different study episodes.
“These results are very important in providing a challenge to this well-established theory,” said senior author Russell Poldrack, director of the Imaging Research Center at the University of Texas at Austin. “There’s something that’s clearly still right about the theory, but this challenges psychologists to reconsider what we know about it.”
Poldrack added: “This helps us begin to understand what makes for effective studying. Sometimes we study and remember things, sometimes we don’t, and this helps explain why.”
Poldrack is a professor in the section of neurobiology and the Department of Psychology at UT Austin. His co-authors were Jeanette Mumford, a statistician at UT Austin; Qi Dong of Beijing Normal University; Xue, of USC and the Beijing Normal University; Zhong-Lin Lu, holder of the William M. Keck Chair in Cognitive Neuroscience and professor of psychology and biomedical engineering at USC College; and Chuansheng Chen of the University of California, Irvine.
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