Summary: During intergroup conflict, oxytocin levels rise and influence activity in the medial prefrontal cortex. This neural response increases empathy and cohesion within the affected group and is associated with a stronger desire to retaliate against rivals. These findings illuminate a possible neurobiological pathway behind how conflicts can spread through social groups.
Source: eLife
New research on the neural mechanisms that drive revenge in group conflicts is published in the open-access journal eLife.
This study indicates that oxytocin — often called the “love hormone” — increases during conflict between groups and modulates the medial prefrontal cortex, a brain region involved in decision-making and social cognition. Increased oxytocin was linked to stronger empathic responses toward harmed ingroup members and to a greater propensity to seek revenge against outgroup members. The results help explain how an initially limited dispute can escalate into wider “conflict contagion,” where hostility spreads across a group.
“The desire for revenge after an attack is universal across human cultures, but the neurobiological processes driving it are not fully understood,” says lead author Xiaochun Han, Doctor of Psychology and Neuroscience at the School of Psychological and Cognitive Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University. “Building on earlier work, we propose a neurobiological mechanism linking an ingroup’s pain caused by an outgroup to the drive to retaliate against that outgroup.”
To test this idea, researchers created a controlled neural-behavioral experiment designed to model realistic revenge dynamics during intergroup conflict. Because oxytocin is known to influence ingroup empathy and to shape intergroup interactions, the team measured both endogenous oxytocin and brain activity while participants observed members of their ingroup and an outgroup experience pain.
In the experiment, participants watched videos in which either an ingroup or an outgroup member received a brief electric shock. In one condition (the “Revenge” group), the shock appeared to be delivered intentionally by the opposing group member; in the other condition (the “Control” group), the shock was described as caused by a computer. Researchers collected saliva samples to measure oxytocin levels and recorded brain responses using functional magnetic resonance imaging (fMRI).
Results showed that participants in the Revenge condition had higher oxytocin levels than those in the Control condition. Higher oxytocin predicted greater activity in the medial prefrontal cortex in response to seeing ingroup members in pain. Crucially, this medial prefrontal activity mediated the relationship between oxytocin and the participant’s later willingness to inflict painful shocks on outgroup members, even when those outgroup individuals had not directly harmed the participant. In other words, the hormonal and neural responses to ingroup suffering were linked to a broader readiness to retaliate against the perceived adversary.
“Our experiment allowed us to examine how harm inflicted on one ingroup member by an outgroup member can motivate uninvolved ingroup members to retaliate,” explains senior author Shihui Han, Professor of Psychology and Principal Investigator at PKU-IDG/McGovern Institute for Brain Research, Peking University. “These results identify a neurobiological pathway that may underlie the spread of conflict across individuals in group contexts.”
The authors note several motivations that can drive revenge in group contexts, including perceived threat, empathic concern for harmed group members, and social pressure to defend or avenge the group. They emphasize that further research is needed to disentangle these motives and the emotional dynamics that trigger retaliatory behavior in different social settings.
Source: eLife
Media contact: Emily Packer – eLife
Image source: The image is in the public domain.
Original research: Open access. Article title: “A neurobiological association of revenge propensity during intergroup conflict.” Authors: Xiaochun Han, Michele J. Gelfand, Bing Wu, Ting Zhang, Wenxin Li, Tianyu Gao, Chenyu Pang, Taoyu Wu, Yuqing Zhou, Shuai Zhou, Xinhuai Wu (corresponding author), and Shihui Han. eLife. DOI: 10.7554/eLife.52014.
Abstract
Revenge during intergroup conflict is a widespread human response, but its neurobiological basis remains unclear. This study combines functional MRI and measurements of endogenous oxytocin in participants who observed ingroup and outgroup members suffering either due to intentional actions by the outgroup (Revenge group) or due to a computer (Control group). The Revenge condition produced elevated salivary oxytocin relative to Control. Medial prefrontal cortex activity in response to ingroup pain mediated the association between increased endogenous oxytocin and the propensity to deliver painful shocks to outgroup members, independent of direct personal involvement. These findings identify an important neurobiological correlate of revenge propensity and suggest mechanisms that may contribute to conflict contagion among social groups.