A group of neuroscientists led by Justin Halbert of Bard College have discovered that people who try to suppress unwanted memories can inadvertently forget the events of the moment. The research is published in the journal Nature Communications.
Scientists conducted an experiment with 381 volunteers aged 18-35. The subjects were asked to memorize such pairwise related words as "jump-ballet", "diet-cream" or "pump-oil" - a total of 36 pairs of words. During testing, participants were asked to either remember the second word from a certain pair, or not think about it. The subjects were shown photographs of unexpected objects in common places, such as a peacock in a car park or a soccer ball on a dining table. Participants were asked to mentally explain how the objects got there.
During the experiment, the brains of the volunteers were scanned using magnetic resonance imaging to determine which areas were most active during tasks.
At the next stage of the experiment, the researchers showed similar images to the volunteers, but this time only the background was present in the picture, and the objects were absent. Participants were asked to remember what was shown in the photographs earlier.
Scientists found that when subjects suppressed memories of words in associations, they were less likely to remember what was depicted in the photographs that were shown to them at that moment. Moreover, the data of magnetic resonance imaging showed that the part of the brain that is responsible for the formation of new memories - the hippocampus - showed reduced activity.
Scientists at the University of Texas at Dallas have previously shown that negative thoughts also greatly impair working memory in humans. Moreover, if the depressive state precedes the memorization process, then their negative effect is maximal.
