Leader–follower behavioural coordination and neural synchronization during intergroup conflict

Abstract

Leaders can launch hostile attacks on out-groups and organize in-group defence. Whether groups settle the confict in their favour depends, however, on whether followers align with leader’s initiatives. Yet how leader and followers coordinate during intergroup confict remains unknown. Participants in small groups elected a leader and made costly contributions to intergroup confict while dorsolateral prefrontal cortex (DLPFC) activity was simultaneously measured. Leaders were more sacrifcial and their contribution infuenced group survival to a greater extent during in-group defence than during out-group attacks. Leaders also had increased DLPFC activity when defending in-group, which predicted their comparatively strong contribution to confict; followers reciprocated their leader’s initiatives the more their DLPFC activity synchronized with that of their leader. When launching attacks, however, leaders and followers aligned poorly at behavioural and neural levels, which explained why out-group attacks often failed. Our results provide a neurobehavioural account of leader–follower coordination during intergroup confict and reveal leader–follower behavioural/neural alignment as pivotal for groups settling conficts in their favour.