Research on the contribution of obsessive beliefs to specific subtypes of obsessive–compulsive disorder (OCD) has been limited to the use of self-report measures. The current investigation used in vivo assessments of ordering and arranging, checking urges, contamination avoidance, and hand-washing to evaluate the relationships between beliefs about perfectionism and intolerance for uncertainty, responsibility and threat estimation, and importance and control of thoughts, as measured by the Obsessive Beliefs Questionnaire-44, with symptoms of OCD. Through four separate studies (N = 566), we found that perfectionism and intolerance for uncertainty beliefs were uniquely predictive of performance on behavioral tasks involving ordering and arranging, checking, and washing. Contrary to hypotheses, responsibility and threat beliefs were not uniquely associated with any task performance variable, and no obsessive belief domain was predictive of contamination behavioral approach. Theoretical and clinical implications of these findings are discussed.
