UMD Researcher, Collaborators Identify Biological Bases of Revenge


Michele Gelfand

UMD Professor Michele Gelfand

“[This is] a new and important finding that could help explain how conflicts escalate—and become contagious from individuals to entire groups,” said co-author and Distinguished University Professor Michele Gelfand.

Researchers Identify Biological Basis of Revenge

Brain Scans Reveal Relationship-Building Response among Groups United by Threats

Acts of conflict and revenge appear to have biological bases, according to an experimental study by Chinese researchers and University of Maryland psychology professor.

Published in the journal eLife, the new study found that when members of a group observe one of their own being hurt by a member of another group, a complex brain response is activated. The biological response includes a release of oxytocin, the so-called “love hormone,” which is linked to empathy and plays a role in relationship building between individuals and within groups.

Subsequent imaging of group members’ brains showed that they experienced common neurological activity that predicted a desire to seek revenge on members of the other group.

“They didn’t just want revenge against the individual who hurt their in-group member, but against the other outgroup members who weren’t originally involved in the conflict,” said study co-author Distinguished University Professor Michele Gelfand. “That’s a new and important finding that could help explain how conflicts escalate—and become contagious from individuals to entire groups.”

Gelfand—who is widely known for research into how groups react to outside threats—approached study senior author Shihui Han, a neuroscientist at Peking University and world expert on the mechanisms of empathy, with the idea of applying his empathy research to look at revenge. “How would you like to take your work on empathy to the dark side—to study revenge”, she asked him in a meeting in Beijing.

The experiment involved creating groups of test subjects in a laboratory. Members of one group were shown images of a compatriot feigning pained reactions to electric shocks from members of another group in the context of a game. Separately, a control group observed one of its members receiving shocks at the discretion of a computer, rather than a member of another group.

Those who witnessed shocks being administered by a member of another group experienced a release of oxytocin, measured in saliva. FMRI scans showed that levels of oxytocin predicted enhanced medial prefrontal cortex activity that correlated to a later urge to administer painful electric shocks to members of the other group.

Members of the control group who witnessed computer-administered shocks did not experience the same responses, or seek to take revenge against the other group.

Gelfand, who developed what she termed the “tightness-looseness” theory to explain how groups with varying strengths of social norms and behavioral restrictions respond differently to outside threats and other stimuli, said she hopes to expand the study to include other cultures to learn what is universal and culture-specific regarding the neurobiology of revenge.

“Is that same neurobiological pathway as strong in a place like the United States, where we have a ‘looser,’ more individualistic culture? That is one question I hope to pursue,” Gelfand said.

Ultimately, findings from this current study and related future studies could be used as a basis to study intractable conflict around the globe.

“Across history, we see this behavior where conflicts escalate across time to include people who were never involved in the conflict,” Gelfand said. “You may not even have been alive for a conflict, but simply hearing a story about how an out-group member harmed your in-group member could potentially activate that neurobiological pathway that predicts revenge-seeking behavior—something we want to investigate in the future.”

Contact: Laura Ours, lours@umd.edu, 301-405-5722

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