Internal monitoring deficits attenuate post-error slowing in psychosis-proneness.

Background: Error processing supports belief updating, failures of which relate to delusions - a hallmark of psychosis. Although deficits in error processing have been observed in individuals with psychotic symptoms, the mechanisms remain unclear. Here, we investigated post-error cognitive adjustment and internal performance monitoring as two potential mechanisms. Methods: In Study 1, we used a Flanker Task and Drift Diffusion Model to measure post-error cognitive adjustments. In Study 2, we introduced false feedback on half the blocks. Both samples are recruited from Prolific. In addition to post-error slowing (PES), we computed post-false slowing (PFS) and post-negative slowing (PNS) to measure self-monitoring and negative feedback responsivity. Sensitivity ( Results: In Study 1, positive schizotypy was associated with less PES and post-error changes in decision threshold and non-decision time. In Study 2, positive schizotypy associated with lower sensitivity and criterion for false feedback detection. Participants higher in this trait also had lower PNS and PFS in the random feedback condition. Lower sensitivity, but not criterion partially mediated the associations between positive schizotypy and PES, PFS, and PNS. Conclusions: People with positive schizotypy show both reduced post-error cognitive resource allocation and poor internal performance monitoring. However, only the latter appears to explain their reduced PES, PFS, and PNS. This finding suggests a role of internal error monitoring impairment in generating and maintaining false beliefs.