A new study has found that it is possible to remember specific information such as faces or words effectively if the pattern of brain activity is consistent each time the information is read.
"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," said Poldrack.
The research represented the first time scientists have analyzed human memory by examining the pattern of activity across many different parts of the image called voxels.
"The question is how practice makes perfect. If you precisely reactivate the same pattern each time, then you are going to remember better," said Gui Xue of the University of Southern California.
The researchers conducted three studies at Beijing Normal University in which subjects were shown different sets of photographs or words multiple times in different orders.
The scientists recorded subjects' brain activity while they studied the material.
They were asked to recall or recognize those items between 30 minutes and six hours later, in order to test the decades-old "encoding variability theory."
That theory suggested people would remember something more effectively if they study it at different times in different contexts than if they review it several times in one sitting.
Based on that theory, the researchers predicted subjects would retain memories of the photos or words more effectively if their brains were activated in different ways while studying that information multiple times.
Instead, the scientists found the subjects' memories were better when their pattern of brain activity was more similar across different study episodes.
The findings were published in the journal Science.