مقاله انگلیسی رایگان در مورد ساختار عصبی اخراج از گروه و خشونت انتقامی – تیلور و فرانسیس 2022

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.

Introduction

     Humans readily categorize people into ingroup and outgroups. This impulse has many consequences – chief of which is the promotion of intergroup conflict and hostility. Indeed, human aggression is often at its most severe against perceived outgroup members (Böhm et al., 2016; Brewer & Kramer, 1985; Cikara, Botvinick et al., 2011; Haslam, 2006; Jackson, 1993; Lickel et al., 2006). Decades of investigation have laid bare many of the psychological processes underlying aggression directed at outgroups, yet the neural mechanisms that subserve such intergroup aggression remain incompletely understood (for a review see, Lantos & Molenberghs, 2021). To add to our understanding, we conducted a functional neuroimaging experiment in which participants were given the opportunity to physically harm (fictitious) ingroup and outgroup targets while we recorded their brain activity. Given the ability of perceived social exclusion to aggravate intergroup hostility (Hales & Williams, 2018), participants were also excluded by outgroup members and then given the opportunity to retaliate against one of them. Together, these procedures sought to simulate an antagonistic intergroup interaction, allowing us to peer into the neural mechanisms that promote hostility toward outgroup members.

Conclusions

     Why does intergroup conflict persist into the modern age? Our findings suggest that aggression toward outgroup members has a robust brain basis that reflects the complex psychological processes involved in such intergroup hostility. We implicated frontostriatal circuits involved in reward processing and social cognition, which may help us understand and intervene upon group-based violence. We hope that future work will seek to replicate and extend these findings in the hope of promoting a more peaceful world.