Sigmund Freud proposed that memories from a traumatic event can be forced from awareness through a process he called repression. Now, reporting in the January 9, 2004, issue of Science, a team of neuroscientists claim they have observed this process—now known as "suppression" of memories—on brain scans. They also found that pushing memories out of consciousness helps to gradually extinguish them. In other words, to forget them.

Participants in the study first memorized pairs of words such as jaw/gum and ordeal/roach. Then, while in a brain scanner, they were presented with only one member of a series of the word pairs. Some participants were asked to recall the other word in the pair, while others were asked to consciously suppress the matching word from their awareness for 4 seconds.

The scans indicated that two brains regions were unusually active when study participants were actively blocking memories: the dorsolateral prefrontal cortex and the hippocampus. The hippocampus, in particular, is central to the process of creating new memories of events and then consciously recalling them later. Later, the people were tested for how well they could accurately recall word pairs. Compared to previously memorized word pairs not presented during the study, recall for the suppressed pairs was less accurate. If confirmed, the study could offer insight into how we subtly edit traumatic and upsetting memories.

Further Reading:

• “Neural systems underlying the suppression of unwanted memories,” by Michael C. Anderson, PhD, and others. (Science, January 9, 2004, Volume 303, Number 20, pp. 232-235.)