Psychosis-proneness is associated with reduced cognitive error-monitoring during instrumental learning.

Background: People higher in psychosis-proneness tend to resist belief revision despite contradictory evidence, potentially due to impaired error-monitoring. Post-error slowing (PES), one measure of error-monitoring, is linked to working memory (WM) recruitment. With limited WM capacity, psychosis-proneness could impair belief updating through poor error-monitoring during instrumental learning. Methods: 153 participants from Prolific were included in final analyses. To investigate how error-monitoring may explain impaired belief updating among those with psychosis-proneness, we implemented a Visuomotor Reinforcement Learning Task with varying WM loads, Interpretation Inflexibility Task, and Multidimensional Schizotypy Scale - Brief. Results: Participants with higher positive schizotypy showed less PES at lower loads on the visuomotor instrumental learning task. WM capacity was associated positively with PES but negatively with positive schizotypy. Notably, it is only among participants higher in positive schizotypy that reduced PES associated with more severe belief inflexibility. Conclusions: These results suggest that impaired top-down error monitoring in psychosis-proneness may stem from WM limitations, leading to greater reliance on slower RL-based learning. This cognitive profile might prevent efficient belief adjustment and error correction, connecting executive function deficits in psychosis-proneness to performance monitoring and cognitive inflexibility.