Many people—particularly readers of pop psychology—assume that if you push an unpleasant or traumatic memory to the back of your mind, it will stick around in your unconscious and eventually come back to haunt you. “The notion that suppressed memories persist in the unconscious, undermining mental health, has permeated our culture since it was first introduced over a century ago by Freud,” Michael Anderson, a cognitive psychologist at Cambridge University, told me via email. But according to a new paper co-authored by Anderson in the journal Proceedings of the National Academy of Science, suppressing unpleasant memories might be an effective way to minimize their impact on mental health: “We found that, surprisingly, suppressing a memory doesn’t simply push it into the unconscious, but actually disrupts unconscious expressions of memory, contrary to what people have long assumed."
A team of psychologists led by Anderson and Pierre Gagnepain of the French Institute of Health and Medical Research had 24 participants study a series of randomly generated word-picture pairs—for instance, the word “duty” and a picture of binoculars—until they came to associate the word with the image: When they saw the term “duty,” they would think of binoculars. Then, the researchers administered a memory test under two conditions. In one condition, participants were given the cue words and told to avoid thinking about the images they’d come to associate with them. In the second condition, they were given the cues and instructed to remember the images.
In the next part of the experiment, they would be given a cue word and then shown a jumble of images; their task was to pick out the picture associated with the cue word. It turned out that the people in the first, or “no-think,” condition took longer to pick the target picture out of the group of images—indicating that they had succeeded in weakening the association that existed in their own memory.
Gagnepain and his team also used fMRI to monitor participants’ brain patterns throughout the experiment, and found that suppressing the memories actually interfered with activity in the area of the brain that deals with visual information. When people tried to block their memories, explained Gagnepain, “A specific region of the prefrontal cortex would shut down activity to prevent a memory from entering consciousness.”
Active forgetting, or suppressing, he said, "is not intrinsically a problem. Sometimes it is adaptive, and useful.” He hopes his findings will have implications for the way psychologists treat trauma and PTSD. Psychologists treating PTSD generally assume that talking about memories will lessen their power, but Gagnepain's findings suggest suppression could also achieve a positive result.
Other psychologists, though, aren’t convinced.
“It was a real stretch for the paper to even talk about traumatic situations,” said Steven Berkowitz, director of the Center for Youth and Family Trauma Response and Recovery at the University of Pennsylvania. He added that Freud never condemned suppression the way Gagnepain insinuates. “Freud never said that repression couldn’t be effective for some individuals. It’s in people who are symptomatic [of PTSD] that repression has failed.”
Other psychologists point out that the pictures in the experiment weren’t exactly emotive.
“There’s nothing traumatic about these materials,” said Elizabeth Loftus, a professor of psychology and social behavior at the University of California, Irvine. “They’re linking it to trauma so they can seem like it has practical implications.”
Dr. Terri Weaver, a professor of psychology at Saint Louis University who has studied PTSD, also cautioned against reading too much into Gagnepain’s findings. “Viewing a depersonalized, standardized picture in the lab is very different from personally experiencing a traumatic event,” she said. “When a person has post-traumatic stress disorder, just trying to put that out of your mind does not work.”
Gagnepain doesn’t think the controlled setting of his experiment renders it less useful.
“If we can pinpoint the exact neural mechanisms engaged when people suppress memories in a control situation," he said, "it might help us understand the circumstances under which this mechanism is disrupted, as in PTSD, and to improve people's ability to control memories.”