Bias against Disconfirmatory Evidence in a large Nonclinical Sample: Associations with Schizotypy and Delusional Beliefs

Bias against disconfirmatory evidence (BADE) is associated with delusion-like ideation and delusion-related aspects of schizotypy in nonclinical populations. Using a well-validated BADE assessment, we sought to demonstrate that only one of two facets of BADE (Evidence Integration Impairment, but not Positive Response Bias) accounts for these associations. To this end, 738 MTurk participants completed a survey which included the Schizotypal Personality Questionnaire (SPQ) and a version of the aforementioned BADE assessment. Using multiple regression, it was found that only Evidence Integration Impairment accounted for unique variance in delusion-related SPQ subscale scores. These results suggest, consistent with our hypothesis, that Evidence Integration Impairment might solely account for previously observed associations between BADE more generally and various cognitions/personality traits. It follows from this suggestion that in the general population ambiguous situations may combine with cognitive biases to maintain delusion-like ideation.