Confusing action and imagination: action source monitoring in individuals with schizotypal traits

To explore whether schizotypal traits may undermine source monitoring for actions, 67 undergraduate participants (21 men) completed the Schizotypal Personality Scale and were then given a source-monitoring task in which some specific acts had to be performed, whereas others only had to be imagined. Next, participants had to complete an old-new recognition task and ascribe the source, i.e., whether they had performed or only imagined the items (i.e., source monitoring). Participants also completed a working memory capacity task (i.e., Operation Span task). We found that the higher the Schizotypal Personality Scale scores, the poorer recognition and source attribution scores. Relative to participants with low levels of schizotypal traits (i.e., controls), those with higher levels of schizotypal traits more often falsely claimed to have performed actions when in fact they had only imagined them. Although participants high and low in schizotypical traits did not differ in their working memory capacity, poor working memory capacity was related to source misattribution (i.e., increase false alarms). The present findings indicate that schizotypal traits undermine source monitoring for action in a healthy population.