Disposition towards hallucination and subjective versus objective vividness of imagery in normal subjects

In the present study we investigated the relation between subjective and ob jective indices of vividness of imagery and disposition towards hallucinati on in 74 college students. Self-reported imagery vividness was measured wit h the visual and auditory subscales of the Betts QMI Vividness of Imagery S cale. The objective task concerned the difference between a perceptual and an imagery condition of judgment of visual similarity of named objects. In addition, subjects completed a hallucination questionnaire (the Launay-Slad e Hallucination Scale). After assigning subjects to a high and a low scorin g group on the basis of scores on the hallucination scale, analysis of vari ance revealed a significant interaction between group and the two vividness of imagery measures. Subjects reporting hallucinatory experiences tended t o show higher imagery vividness ratings on the Betts Scale than nonhallucin ating subjects. In contrast, the reverse relation was found on the experime ntal imagery task. Implications of these findings for the validity of self- report imagery vividness measures are discussed. Directions for future rese arch are outlined. (C) 1999 Elsevier Science Ltd. All rights reserved.