In this study, the investigators examine whether emotional and social reward from alcohol varies depending on the social context of consumption.

Objective: Although the vast majority of alcohol consumption outside the laboratory occurs in social context, experimental studies of alcohol's emotionally reinforcing effects have overwhelmingly examined individuals drinking in isolation. The current study examines motivationally salient elements of everyday social drinking contexts as moderators of alcohol-related reinforcement. More specifically, the present study examine whether alcohol is more reinforcing within the context of unfamiliar vs. familiar social interaction and, further, whether alcohol is more reinforcing within the context of low vs. high quality social relationships. The current study furthermore examine whether individuals with characteristics that put them at risk for developing an alcohol use disorder (e.g., male gender, impulsive/extraverted personality profile, heavy patterns of consumption, family history of AUD, ...) exhibit heightened emotional reinforcement from alcohol within these social drinking contexts.

The current project represents a test of competing theories of alcohol reinforcement. Alcohol myopia theory-which has heretofore represented the most prominent theory of alcohol's effects-predicts that alcohol's ability to relieve stress depends on the nature (positive or negative) of stimuli in the drinker's immediate environment. Alcohol myopia theory might thus predict that alcohol's rewarding effects will be larger within familiar interactions and within secure relationships. In contrast, the social attributional theory of alcohol reinforcement predicts that alcohol-related reinforcement will be most pronounced within the context of unfamiliar social interactions.

In addition to providing an opportunity to test contextual and individual-level moderators of alcohol reinforcement, the current study represents an opportunity to directly test the replicability of research indicating a pronounced reinforcing effect of alcohol specifically within interactions among unfamiliar individuals (Sayette et al., 2012; Fairbairn et al., 2013).

Study Population: Participants will consist of 640 male and female drinkers, aged 21-30, with no reported history of severe alcohol use disorder. Participants will be sampled such that at least 360 of these participants will classify as heavy drinkers.

Design: In the laboratory arm of the study, individuals will be randomly assigned to consume either a moderate dose of alcohol or a control beverage in the company of either familiar or unfamiliar individuals. Of these individuals, a subset will participate in additional tasks post beverage-consumption including a hyperscanning EEG task, while an additional subset will also participate in an ambulatory assessment period over the course of several weeks to examine the interaction of alcohol and social contextual factors in daily life. In the ambulatory study arm, participants will wear transdermal sensors to assess BAC and will further provide information about their mood and their social contexts in response to random prompts.

Outcome Measures: Primary outcome measures include self-reports of positive and negative mood and perceived social reinforcement. The investigators will also examine facial expressions using the Facial Action Coding System, a comprehensive, anatomically-based system for categorizing facial muscle movement. One aim of the current study is to examine whether differential reinforcement from alcohol in unfamiliar social contexts emerges only with respect to self-reports, or is also observable within facial behaviors. EEG/ERP measures will also be examined for a subset of participants engaged in a hyperscanning task.

Inclusion Criteria:

• Between the ages of 21 and 30
• Currently drinks alcohol
• Able to provide at least 2 same-gender friend referrals

Exclusion Criteria:

• Female participant is pregnant or trying to become pregnant
• Endorsed medical disorder caused by, or made worse by, alcohol
• History of severe alcohol problems
• Use of drugs known to interact with alcohol

May be either male or female, but must be same as gender assigned at birth.

Primary participants in the current study consisted of both eligible individuals who first contacted the lab and their eligible friends. Here we report the total number of individual participants (both initial contacts and their friends) enrolled in the study.

6-9 hours (length of the laboratory session)

The intervention of the study is laboratory alcohol administration.