The Modulation of Reward Expectancy on the Processing of Near-miss Outcomes: An ERP Study

A near-miss is a situation in which a gambler almost wins but falls short by a small margin, which motivates gambling by making it feel like success is within reach. Existing research has extensively investigated the influence of contextual information on near-miss outcome processing; however, the impact of reward expectancy has received limited attention thus far. To address this gap, we utilized the wheel of fortune task and event-related potential technique (ERP) to quantify the electrophysiological responses associated with gambling outcomes at different levels of reward expectancy. Behaviorally, near-miss outcomes elicited a greater occurrence of counterfactual thoughts, feelings of regret, and heightened anticipation of rewards for subsequent trials compared to full-miss outcomes. ERP findings indicated that in contrast to full-miss outcomes, near-miss outcomes diminished feedback-related negativities (FRNs) and amplified P300s when reward expectancy was low, but amplified FRNs and diminished P300s when reward expectancy was high. These findings provide valuable insights into the neural mechanisms underlying the processing of outcome proximity and reward expectancy.