Suppressing Guilty Memories Reduces Their Impact On Unconscious Behavior

We can successfully suppress some incriminating memories and reduce their impact on our automatic behaviors. Photo courtesy of Shutterstock.

Think, for a second, about your most shameful moment. Would you like to simply erase your guilty memory same as you might delete a word? New research indicates all is not lost: We can successfully suppress some incriminating memories and reduce their impact on our automatic behaviors.

Interestingly, some traces of guilt remain.

“A century-old question is whether suppressed memories can nevertheless influence people’s behavior in a less conscious, more automatic manner than they would if they had not been suppressed,” began the authors. To answer this question, Dr. Xiaoqing Hu, a professor in the psychology department at University of Texas, and his colleagues recruited 78 undergrads and assigned them to one of three groups.

Two guilty groups were instructed to find and steal a ring from a faculty member’s mailbox. A third innocent group was told to go to the mailboxes and write their initials on a piece of poster board.

Next, the researchers told the first guilty group that they should suppress the memory of stealing the ring and not allow it to come to mind during a concealed-information test (CIT). The other guilty students and the innocent students were not given any instructions. Then, all three groups completed a CIT, a brainwave-based test that evaluates involvement in a crime.

During the testing, researchers presented the target word (ring) and crime-irrelevant words, such as bracelet or watch. Meanwhile, participants’ brain activity was recorded using an EEG. The participants also completed an autobiographical Implicit Association Test (aIAT). Here, they had to indicate whether specific statements were true or false — the faster the response, the more strongly held the association is (regardless of what someone claims to believe).

So, what did the tests show?

Thought Police

The guilty participants P300 responses — a brainwave indicating conscious recollection — were larger, significantly so, in response to the target word than to irrelevant words... but only if they had not been given instructions to suppress memories of their crime.

Surprisingly, guilty participants who had suppressed their crime-related memories showed no difference in P300 response to target and irrelevant words. Plus, their data were indistinguishable from that of innocent participants! On the aIAT, the suppressed-memory guilty participants also showed themselves to be similar to the innocent participants and separate from the guilty participants.

These findings suggest that suppression “can render unwanted memories both less consciously accessible and less likely to exert automatic, implicit influences on behavior,” wrote the researchers.

However, the minds of the guilty had not been wiped entirely clean. The guilty-suppressors still could be identified via another brainwave, known as the late posterior negativity. Seemingly, a neural trace of guilty action always remains.

Source: Hu X, Bergstrom ZM, Bodenhausen GV, Rosenfeld JP. Suppressing Unwanted Autobiographical Memories Reduces Their Automatic Influences: Evidence From Electrophysiology and an Implicit Autobiographical Memory Test. Psychological Science. 2015.

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