Hypnotic hallucinations: towards a biology of epistemology

Abstract In a positron emission tomography (PET) study of hypnotic auditory hallucinations (Szechtman, Woody, Bowers and Nahmias, 1998), we found that activation of the right anterior cingulate seems to be critically implicated in the experience of a hallucination. Here we discuss two alternative interpretations of this result, consistent with the known functions of this region. First, hallucinations may occur when affect drives the generation of an internal percept, and then outwardly directed attention leads to the misattribution of this percept to the external world. This interpretation is consistent with the model of hallucinations by Bentall (1990). Alternatively, hallucinations may stem from what we herein term a ‘feeling of knowing’, or conviction that a stimulus is out there, around which the hallucinator constructs and rationalizes a percept. We relate the latter proposal to ideas by Rapoport (1989) and Damasio (1994) concerning the biological underpinnings of the sense of external reality. We also suggest ways that research on the neural bases of hypnosis might offer clues about the neural bases of psychopathologies, such as obsessive‐compulsive disorder and schizophrenia. Copyright © 2000 British Society of Experimental and Clinical Hypnosis