An ERP study of expectation violation in a social comparison context

Previous studies pay more attention to the cognitive control in classical cognitive conflict task but the time-course of the expectation violation in a social comparison context remains unknown. Event-related potentials (ERPs) were recorded to explore the electrophysiological correlates of expectation violation by using a reward feedback paradigm in a social comparison context. Results showed that: Expectation incongruent stimuli (EIS) elicited a more positive ERP deflection (P400-700) than did expectation congruent stimuli (ECS) between 400 and 700 ms. Furthermore, dipole source analysis revealed that the generator of P400-700 was localized near the posterior cingulate gyrus (PCC), which might be involved in the monitoring and controlling of reward expectation conflict (expectation violation). EIS also elicited a more negative ERP deflection (N1000-1500) than did ECS between 1,000 and 1,500 ms. The generator of N1000-1500 was localized near the parahippocampal gyrus, which might be related to unpleasant emotions induced by a lack of reward feedback.