The Effects of Alcohol in Groups of Heavy Drinking Young Adults: A Multi-Modal Investigation of Alcohol Responses in a Laboratory Social Setting.

Young adults typically drink socially, yet most lab studies testing alcohol responses have administered alcohol in isolation. This is the first study to examine alcohol responses and social reward in a group setting among a young adult at-risk sample. Heavy drinking young adults (N=393; 50% female) were grouped in threes and drank a moderate dose of alcohol or a placebo. These social interactions were recorded, and the duration and sequence of facial expressions, speech, and laughter were coded. Results revealed a comprehensive, multimodal, positive effect of alcohol on socioemotional experiences across self-report (e.g., increased positive affect and social bonding, greater relief of unpleasant feelings) and behavioral outcomes at both the individual- (e.g., more rapid increases in Duchenne smiling) and group-levels (e.g., more three-way conversations). Findings underscore the potential for group-formation paradigms to yield valuable data regarding etiological mechanisms underlying alcohol use disorder. All data and code are available (https://osf.io/3q42z/).