Brain responses and susceptibility to peer influence on drinking

Conversations shape future behaviors. However, individuals vary in susceptibility to conversational influence and in neural responses tracking such influences. We examined whether activity in brain regions associated with social rewards and making sense of others’ minds relates to a common behavior—drinking, following conversations about alcohol. We studied ten social groups of college students (N = 104 students; 4760 total observations) across two University campuses. We collected whole-brain fMRI data while participants viewed photographs of peers with whom they tended to drink at varying frequencies. Next, using ecological momentary assessment, we tracked alcohol conversations and drinking twice daily for 28 days. On average, talking about alcohol was associated with a higher probability of next-day drinking. Controlling for baseline drinking, participants who responded more strongly to peers with whom they drank more frequently—in brain regions associated with social rewards and mentalizing—showed higher susceptibility to conversational influence on drinking. Conversely, stronger neural responses to peers with whom they drank less frequently decoupled the link between alcohol conversations and next-day drinking. We conceptually replicate prior findings linking conversations and drinking in a longitudinal setting and provide new evidence that brain sensitivity to peers may exacerbate or buffer conversational susceptibility to drinking.