Decomposing perseverative errors among undergraduates scoring high on the Schizotypal Personality Questionnaire.

Cognitive control (CC), the capacity to flexibly direct resources to a goal by selecting and integrating relevant contextual information, is impaired among persons with schizophrenia-spectrum disorders. CC is achieved, in part, through shifting one's cognitive set towards stimuli of task relevance. Set-shifting deficits typically result in perseverative errors, like those captured by the Wisconsin Card Sorting Test (WCST). However, a disadvantage of the WCST is that it confounds the potential sources of perseverative errors. The Dimensional Change Card Sorting Task (DCCS), in contrast, allows for the decomposition of perseverative errors by systematically varying the shape and/or color of stimuli across pre-switch, switch and post-switch trials. Using these techniques previous research has evaluated the separable contributions of negative priming, positive priming, and extra dimensional shifting to the production of perseverative errors. In the current study, college students scoring high on the Schizotypal Personality Questionnaire (High-SPQ; Raine, A., 1991. The SPQ: a scale for the assessment of schizotypal personality based on DSM-III-R criteria. Schizophr. Bull. 17 (4), 555-564.) and average scoring individuals (Ave-SPQ) were administered the DCCS to investigate schizotypal-related mechanisms underlying set-shifting abnormalities. Relative to Ave-SPQ, High-SPQ participants showed more perseverative responses that were restricted to the positive priming post-switch condition. Possible mechanisms of this impairment, including depletion of cognitive resources and differences in strategy commitment, are discussed.