Ventrolateral prefrontal cortex activation during social exclusion mediates the relation between intolerance of uncertainty and trait aggression.

Intolerance of uncertainty (IU) is an important individual difference factor that may contribute to trait-like aggression. Deficient engagement of the ventrolateral PFC (vlPFC) during social situations may also be a mechanism that links these two constructs. The aim of the current study was to test a proposed mediation model whereby IU is associated with trait aggression through neural activation of the vlPFC during a social exclusion task. Fifty-three adults with a range of impulsive-aggressive traits completed validated assessments of IU and trait aggression, and the 'Cyberball' social exclusion task during functional magnetic resonance imaging (fMRI). Results supported the mediation model such that greater levels of IU were associated with greater trait aggression through hypoactivation of the vlPFC during social exclusion. This study is the first to provide evidence suggesting that individuals higher in IU have difficulties engaging regulatory neural processes, which in-turn may increase the propensity for aggression.