A NOTE to the forgetful: failing to remember everything is a sign your brain is working properly. So says a study that found that the brain not only chooses to reinforce memories it deems most relevant, but actively suppresses those that are similar but less-used.
Brice Kuhl at Stanford University in California and his colleagues used functional magnetic resonance imaging (fMRI) to measure the brain activity of 20 healthy adults while they performed a simple memory test. Participants were given three word pairs to memorise, two of which were closely associated with each other. After studying one of the associated pairs for a second time, subjects were asked to recall all three pairs. On average, people were 15 per cent worse at recalling the associated pair they had seen once than they were at recalling the unrelated pair.
The fMRI scans showed that during the test, participants鈥� brains were highly active in a region known to handle competing memories and another believed to induce memory suppression. As the test was repeated, the level of suppression lessened, indicating the memory adjustment had been made (Nature Neuroscience, DOI: 10.1038/nn1918).
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鈥淭he process of forgetting serves a good functional purpose,鈥� says Michael Anderson of the University of Oregon in Eugene. 鈥淭hese guys have clearly established the neurobiological basis for this process.鈥�
