Alcohol's effects on decision making and cognitive processing in a reward uncertainty task

Alcohol impairs judgment, often increasing risk-taking behaviors such as reckless driving and gambling, which can result in severe consequences. However, laboratory studies have inconsistently observed alcohol-induced risk taking, raising questions about the specific contexts in which these effects emerge. This study investigated alcohol's impact on decision making within a reward uncertainty framework.

Participants were given a moderate dose of alcoholic (N = 40), placebo (N = 40), or a nonalcoholic drink (N = 42) before completing a validated Reward Uncertainty Task in which they chose between certain and uncertain monetary rewards.

Nonintoxicated participants demonstrated an expected aversion to uncertainty, favoring certain rewards even when objectively less advantageous. Alcohol appeared to reduce this reward uncertainty aversion. No placebo effects were observed, indicating a pharmacological rather than expectancy effect. We also explored the neural mechanisms underlying these behaviors using the P3 event-related potential. Alcohol significantly attenuated the P3 response to choice presentations, reflecting disrupted cognitive processing, potentially facilitating riskier choices.

These findings complement previous research that showed alcohol dampens responses to uncertain aversive stressors, with a novel extension from aversive to appetitive domains. Future research should explore nuances in these effects to help aid targeted interventions for mitigating alcohol's negative impact on decision making. (PsycInfo Database Record (c) 2026 APA, all rights reserved).