Inter-group conflicts drive human discrimination, mass migration, and violence, but their psychobiological mechanisms remain largely unknown. Here, we investigated whether the neuropeptide oxytocin modulates behavior and spatio-temporal brain dynamics in naturalistic inter-group conflict. Eighty-six male members of natural rival social groups received either oxytocin or placebo intranasally. In a decision-making paradigm involving real monetary stakes, participants could sacrifice their own resources to modulate the monetary gains and losses of in- and out-group members. Oxytocin eliminated the reduction in out-group gains - particularly in individuals with low emotional empathy, whereas those given placebo exhibited this negative social behavior. Our spatio-temporal analysis of event-related potentials elicited by outcome valuation revealed that oxytocin replaced a neurophysiological process associated with the negative valuation of out-group gains via a process associated with positive valuation between 200-500ms after outcome presentation. Oxytocin thus seems to modulate inter-group behavior in humans via a specific alteration of valuation-related brain dynamics.

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催产素改变人类群体间冲突的行为和时空大脑动力学

群体间冲突推动了人类歧视、大规模迁移和暴力，但其心理生物学机制在很大程度上仍然未知。在这里，我们调查了神经肽催产素是否调节自然群际冲突中的行为和时空大脑动力学。自然竞争社会群体的 86 名男性成员鼻内接受催产素或安慰剂。在涉及实际货币权益的决策范式中，参与者可以牺牲自己的资源来调节组内和组外成员的货币收益和损失。催产素消除了外群体收益的减少——尤其是在情绪同理心低的个体中，而那些给予安慰剂的人则表现出这种消极的社会行为。我们对结果评估引发的事件相关电位的时空分析表明，催产素通过与结果呈现后 200-500 毫秒之间的正评估相关的过程取代了与组外收益的负评估相关的神经生理过程。因此，催产素似乎通过与估价相关的大脑动力学的特定改变来调节人类的群体间行为。