Uncertain threat is associated with greater impulsive actions and neural dissimilarity to Black versus White faces.

Race is a social construct that contributes to group membership and heightens emotional arousal in intergroup contexts. Little is known about how emotional arousal, specifically uncertain threat, influences behavior and brain processes in response to race information. We investigated the effects of experimentally manipulated uncertain threat on impulsive actions to Black versus White faces in a community sample (n = 106) of Black and White adults. While undergoing fMRI, participants performed an emotional go/no-go task under three conditions of uncertainty: 1) anticipation of an uncertain threat (i.e., unpredictable loud aversive sound); 2) anticipation of an uncertain reward (i.e., unpredictable receipt of money); and 3) no anticipation of an uncertain event. Representational similarity analysis was used to examine the neural representations of race information across functional brain networks between conditions of uncertainty. Participants-regardless of their own race-showed greater impulsivity and neural dissimilarity in response to Black versus White faces across all functional brain networks in conditions of uncertain threat relative to other conditions. This pattern of greater neural dissimilarity under threat was enhanced in individuals with high implicit racial bias. Our results illustrate the distinct and important influence of uncertain threat on global differentiation in how race information is represented in the brain, which may contribute to racially biased behavior.