Old memories interfere with remembering new ones
Scans reveal how the brain juggles outdated and fresh information
As anyone who has typed an outdated e-mail password before finally dredging up the new one knows, it’s easy to remember the wrong thing. Now, by capturing the battle between right and wrong memories in the brain, scientists have found that the struggle can get messy.
The results, published March 7 in the Journal of Neuroscience, bring scientists closer to understanding how people usually manage to pull up the right memory, and what goes wrong when this process fails. “To me, one of the most remarkable things isn’t how much we store in memory, but how well we’re able to find a memory,” says study coauthor Brice Kuhl of Yale University.
To study this battle of new versus old memories in the brain, Kuhl and his team had 24 undergraduates learn a picture-word pair, then learn a different one and finally describe the more recent pair. To create the original memory, participants were twice shown a word above an unrelated picture of a face, an object or a scene. For instance, the word “swim” would appear over a picture of Al Gore.
The researchers then shuffled the association, replacing Gore with an image of the Grand Canyon, and showed the participants the new pair. While in a brain scanner, participants were then shown the word “swim” and asked what kind of picture went underneath it in the newer memory.