Li Chiang-shan Ray, Chen Mon-chu, Yang Yong-yi, Chen Min-chi, Tsay Pei-kwei
Department of Psychiatry, Chang Gung Memorial Hospital, 5 Fu-Hsing Street, Kwei-shan, 333 Tao-Yuan, Taiwan.
Schizophr Res. 2002 May 1;55(1-2):115-28. 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 online processing of perceptual signals.
有人认为，感知性幻觉是由于将自我产生的事件归因于外部来源时出现偏差所致。“自我监测”模型提出，这种损害源于感知决策中缺陷的伴随放电。然而，对精神分裂症患者的心理物理学研究并未找到对该模型的一致支持。我们通过纳入患有情绪障碍的受试者作为患者对照重新探讨了这个问题，并在听觉检测和辨别任务中使用了可变强度的信号。使用信号检测理论，我们发现与对照受试者相比，精神分裂症患者在听觉检测和辨别方面的敏感性降低。此外，精神分裂症患者的心理测量函数斜率比对照组的更浅。根据信号检测的不确定性理论，这表明精神分裂症患者监测的感知通道数量较少。另一方面，有幻觉和无幻觉的精神分裂症患者彼此之间没有差异，并且作为一个群体，他们在反应偏差方面与对照受试者也没有差异。总体而言，我们的结果不支持幻觉是由感知信号在线处理中偏差改变所致的观点。
