Temporal dynamics of reward and memory in face recognition

Several studies have shown that the expectation of a potential monetary reward can enhance memory processes. Although neuroimaging studies have begun to uncover the neural underpinning of reward and memory, the temporal dynamics of these processes are still far from settled. The aim of the present study was to elucidate the mechanism whereby face recognition can be influenced by reward. In order to tap the electrophysiological correlates of face recognition memory, we investigated the event-related potentials (ERPs) elicited in an old/new test in response to faces that, at encoding, were associated with a monetary reward. The use of an old/new paradigm enabled us to investigate the ERP correlates of the memory-related processes associated with the repeated items. The behavioral results are largely consistent with the finding that memory processes interact with reward evaluation, in that faces associated with reward were better recognized than faces associated with a monetary loss. The pattern of ERP responses during encoding showed a robust effect of reward on face processing beginning from very early latencies, with greater amplitudes on frontal and temporal sites for rewarded faces. During retrieval, we found a positive-going component for rewarded faces on frontal sites, probably monitoring the neural correlates of reward-face association. In addition, faces associated with reward elicited larger ERPs components related to memory recognition processes than faces with negative or no reward. These results demonstrate that monetary reward can modulate perceptual processing and increase memory efficiency for human faces.