BACKGROUND: Whereas the effects of modeling and of drinking contexts on alcohol use are documented, studies are lacking regarding the effect of given social exposures on actual alcohol consumption during drinking episodes (i.e., in situ alcohol consumption, the quantity of alcohol actually ingested in given occasion, e.g., in grams). METHODS: Applying the experimental paradigms, our study investigates the impact of social condition (alone vs. with others) on in situ alcohol consumption (analog measurements) of 123 young adults who participated in 2 wine-tasting sessions (one together with others, i.e., group condition; 1 solitary, i.e., individual condition: the sequence of participation was assigned at random). Bivariate and multivariate analyses, that is, paired- and independent-samples t-tests and repeated measure analysis of variance, were applied to investigate the effects through both transversal and longitudinal perspectives. RESULTS: In the first session, higher average amounts of alcohol were consumed in the group condition compared with the individual one. Conversely, higher average consumption was recorded in the individual compared with the group condition in the second session. Considering simultaneously data from the 2 experimental sessions demonstrated that subjects consumed higher amounts of alcohol in individual condition when this condition was organized subsequent and not prior to the group condition. Yet, alcohol consumption in group condition appeared to not vary between the 2 sessions. CONCLUSIONS: Results first highlight the effects of social condition on in situ alcohol consumption. However, they also suggest that in situ exposition to others drinking is possibly involved in shaping the perception of context-related drinking norms, which might further influence subsequent drinking behaviors in an analogous context. Beyond the issues of imitation effects, these findings raise the issues of the development of preventive initiatives aiming to induce changes in individuals' perception of context-specific drinking norms.