Imagery vividness, reality testing, and schizophrenic hallucinations.

Groups of schizophrenics with and without auditory hallucinations and nonpsychotic controls were administered a test of vividness of auditory imagery, participated in a listening task, and were measured on their ability to assess the accuracy of their auditory perceptions. In accordance with the hypothesis, the hallucinators tended to have high, and the nonhallucinators low vividness of auditory imagery. Furthermore, the three groups differed significantly in their ability to assess the accuracy of their auditory perceptions, with the hallucinators demonstrating the greatest inability while the controls were best able to judge the correctness of their auditory perceptions. A model of hallucination formation is proposed in which vividness of auditory imagery and defective reality testing are seen as prerequisite but not necessarily sufficient.