Realism of confidence in obsessive-compulsive checkers

The study examined whether obsessive-compulsive (OC) checkers have reduced confidence in their knowledge. OC checkers were compared with panic disorde r (PD) patients and nonpatient controls using a calibration-of-knowledge pr ocedure. Participants completed a general knowledge questionnaire, rated th eir confidence in each answer, and estimated the total number of correct an swers. These responses were converted to 2 measures of confidence relative to performance-over/underconfidence and over/underestimation, OC checkers h ad lower scores than nonpatients did on both measures, whereas the PD patie nts did not differ from tither group. For the OC checkers, relative confide nce was inversely related to the severity of obsessions. The authors specul ate that confidence may depend on a confirmation bias in testing hypotheses and that the reduced confidence in OC checkers may reflect a disconfirmati on bias in this population.