The impact of alcohol and social context on the startle eyeblink reflex

Researchers have long sought to understand how individuals respond to alcohol in social settings with the aim of elucidating pathways of risk for alcohol use disorder (AUD). However, studies that incorporate a social context are still outnumbered by those that examine alcohol’s subjective effects among participants drinking alcohol in isolation. Further, perhaps due to the challenges of capturing automatic affective processes in these settings, prior studies of alcohol response in social context have relied mainly on self-report measures, and so relatively little is known about alcohol’s psychophysiological effects in social settings. Using a novel paradigm that integrated alcohol-administration procedures, startle methodology, and social context, this study examined the impact of alcohol and social context on startle eyeblink reflex among 40 social drinkers. Results indicated that there was a significant effect of group presence, indicating that startle magnitude was larger when people were alone than with others. There was a significant group presence by alcoholic beverage interaction, with the effect of alcohol being significantly larger when people were alone versus with others. These effects were found both for the startle habituation data and during the picture-viewing task. Results of this study highlight the importance of considering the presence of other individuals for understanding alcohol response and mechanisms of AUD risk. Findings are discussed in light of both emotional and cognitive correlates of startle reflex magnitude. Future research should examine these effects within larger samples of participants and further explore mechanisms that might underlie these effects