Individuals immersed in groups sometimes lose their individuality, take risks they would normally avoid and approach outsiders with unprovoked hostility. In this study, we identified within-group neural synchronization in the right dorsolateral prefrontal cortex (rDLPFC) and the right temporoparietal junction (rTPJ) as a candidate mechanism underlying intergroup hostility. We organized 546 individuals into 91 three-versus-three-person intergroup competitions, induced in-group bonding or no-bonding control manipulation and measured neural activity and within-group synchronization using functional near-infrared spectroscopy. After in-group bonding (versus control), individuals gave more money to in-group members than to out-group members and contributed more money to outcompete their rivals. In-group bonding decreased rDLPFC activity and increased functional connectivity between the rDLPFC and the rTPJ. Especially during the out-group attack, in-group bonding also increased within-group synchronization in both the rDLPFC and the rTPJ, and within-group rDLPFC synchronization positively correlated with intergroup hostility. Within-group synchronized reduction in prefrontal activity might explain how in-group bonding leads to impulsive and collective hostility toward outsiders.

中文翻译：

---

前额叶皮层的组内同步与组间冲突相关。

陷入群体的个人有时会失去自己的个性，冒着通常会避免的风险，以无端的敌对态度与外界接触。在这项研究中，我们确定右背外侧前额叶皮层（rDLPFC）和右颞颞交界处（rTPJ）的组内神经同步是组间敌对性的潜在机制。我们将546人组织为91个3对3人的小组赛，诱导了组内键合或无键合控制操作，并使用功能性近红外光谱仪测量了神经活动和组内同步。在组内绑定（相对于控制）之后，个人给组内成员的钱比给组外成员的钱多，并且捐出更多的钱来击败竞争对手。组内绑定减少了rDLPFC的活动，并增加了rDLPFC和rTPJ之间的功能连接。尤其是在组外攻击期间，组内绑定也增加了rDLPFC和rTPJ中的组内同步，并且组内rDLPFC同步与组间敌对性正相关。组内同步减少前额活动可能可以解释组内联系如何导致对外界的冲动和集体敌视。