The dissociating of reward feedback on familiarity and recollection processing: evidence from event-related potential

Objectives Although previous studies have explored the effect of reward feedback on recognition memory, electrophysiological evidence for reward-enhanced memory and its underlying processing mechanisms remains unclear. Methods This study adopts reward-learning and recognition memory tasks. Participants were asked to learn the reward values of two-color images (each color image had either reward or nonreward feedback) in the reward-learning task, and then tested their recognition memory performance with reward and nonreward feedback items. Results Results demonstrated that the recognition memory performance of rewarded items was better than that of nonrewarded items. During the reward-learning period, nonreward feedback elicited larger feedback-related negativity (FRN) and P300 amplitudes compared with reward feedback. The findings indicated that participants mainly engaged in prediction error processing in the early stage, followed by comparing and context update of the learned items. During the recognition memory period, reward items elicited larger FN400 amplitude and smaller LPC amplitude compared with nonreward items. This suggests that reward item retrieval has deeper memory traces and can identify items faster, relying mainly on familiarity processing. Conversely, nonreward, as a general or inhibitory item, requires more detail and cognitive resources, that is, relies on recollection processing. Conclusions These findings indicated that participants had different process patterns between reward and nonreward items during recognition retrieval.