ABSTRACT

Aggression occurs frequently and severely between rival groups. Although there has been much study into the psychological and socio-ecological determinants of intergroup aggression, the neuroscience of this phenomenon remains incomplete. To examine the neural correlates of aggression directed at outgroup (versus ingroup) targets, we recruited 35 healthy young male participants who were current or former students of the same university. While undergoing functional MRI, participants completed an aggression task against both an ingroup and an outgroup opponent in which their opponents repeatedly provoked them at varying levels and then participants could retaliate. Participants were then socially included and then excluded by two outgroup members and then completed the same aggression task against the same two opponents. Both before and after outgroup exclusion, aggression toward outgroup members was positively associated with activity in the ventral striatum during decisions about how aggressive to be toward their outgroup opponent. Aggression toward outgroup members was also linked to greater post-exclusion activity in the rostral and dorsal medial prefrontal cortex during provocation from their outgroup opponent. These altered patterns of brain activity suggest that frontostriatal mechanisms may play a significant role in motivating aggression toward outgroup members.

摘要

敌对群体之间经常发生严重的攻击行为。尽管对群体间攻击行为的心理和社会生态决定因素进行了大量研究，但这种现象的神经科学仍然不完整。为了检查针对外群体（与内群体）目标的攻击行为的神经相关性，我们招募了 35 名健康的年轻男性参与者，他们是同一所大学的现任或前任学生。在接受功能性核磁共振检查时，参与者完成了针对内群体和外群体对手的攻击任务，其中对手在不同程度上反复挑衅他们，然后参与者可以进行报复。然后，参与者被纳入社会，然后被两个外群体成员排除，然后对同样的两个对手完成相同的攻击任务。在外群体排斥之前和之后，在决定对外群体对手的攻击性时，对外群体成员的攻击性与腹侧纹状体的活动呈正相关。对外群体成员的攻击性也与外群体对手挑衅时头侧和背侧内侧前额叶皮层的排斥后活动增加有关。这些大脑活动模式的改变表明，额纹状体机制可能在激发对外群体成员的攻击性方面发挥着重要作用。