Altered performance of schizophrenia patients in an auditory detection and discrimination task: exploring the ‘self-monitoring’ model of hallucination

• Published in: Schizophrenia research Vol. 55; no. 1; pp. 115 - 128
• Main Authors: Li, Chiang-shan Ray, Chen, Mon-chu, Yang, Yong-yi, Chen, Min-chi, Tsay, Pei-kwei
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.05.2002; Elsevier Science
• Subjects: Adult; Adult and adolescent clinical studies; Attention; Auditory Perception; Auditory Perceptual Disorders - diagnosis; Auditory Perceptual Disorders - psychology; Biological and medical sciences; Bipolar Disorder - diagnosis; Bipolar Disorder - psychology; Depressive Disorder, Major - diagnosis; Depressive Disorder, Major - psychology; Discrimination Learning; Female; Hallucination; Hallucinations - diagnosis; Hallucinations - psychology; Humans; Male; Medical sciences; Pitch Discrimination; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Psychoses; Reference Values; Response bias; Schizophrenia; Schizophrenia - diagnosis; Schizophrenic Psychology; Signal detection theory; Signal Detection, Psychological; Schizophrenia; Response bias; Signal detection theory; Hallucination; Auditory perception; Human; Mood disorder; Education level; Sex; Cognition; Experimental study; Discrimination task; Psychosis; Symptomatology; Hearing; Age of onset; Sociodemographic factor; Information processing; Perception; Age; Signal detection; Comparative study; Cognitive bias
• ISSN: 0920-9964; 1573-2509
• DOI: 10.1016/S0920-9964(01)00203-1

It has been suggested that perceptual hallucination results from a bias in attributing a self-generated event to an external source. The ‘self-monitoring’ model proposes that the impairment arises from a defective corollary discharge in perceptual decisions. However, psychophysical studies in schizophrenia patients have not found consistent support for the model. We re-explored this issue by including subjects with mood disorders as patient controls and employed signals of variable intensities in an auditory detection and discrimination task. Using signal detection theory, we found decreased sensitivity in auditory detection and discrimination in schizophrenia patients, as compared to control subjects. Moreover, the psychometric functions of schizophrenics had a shallower slope than those of the controls. According to the uncertainty theory of signal detection, this suggested that schizophrenia patients monitored a smaller number of perceptual channels. On the other hand, hallucinating and non-hallucinating schizophrenia patients did not differ from each other, nor did they as a group differ from control subjects in terms of response bias. Overall, our results do not support the idea that hallucination results from an altered bias in the on-line processing of perceptual signals.