An Investigation of Response Bias in the Chapman Scales

In this study, the major response sets that can adversely affect the validity and usefulness of trait scales are briefly described. Representative response set measures are then used to assess the degree to which scores on four of the Chapman Scales, which reportedly measure traits associated with psychosis proneness, are determined by such content-irrelevant factors. Evidence suggested that interpretations of the Chapman Scales were confounded by response set biases, and that the Chapman Scales have been simply measuring, to a considerable extent, the tendency of subjects to give socially desirable responses in self-description. Multiple regression and correlation techniques indicated that socially desirable and acquiescent response styles account for as much as 25% of the total variance in the Perceptual Aberration, Magical Ideation, and Impulsive Nonconformity Scales. However, no reliable response set predictors were identified for the Physical Anhedonia Scale. Results demonstrated that normal subjects were able to identify keyed responses on each of these selected Chapman scales, and successfully to fake their scores.