Perceptual Deficit in Schizophrenia: A Defect in Redundancy Utilization, Filtering or Scanning?

Abstract

SummaryThe perception by schizophrenic patients of stimuli with more than one feature (dimension) was investigated using psychiatric and non-psychiatric control groups. Indices of the ability (a) to make use of redundant stimulus cues, (b) to ‘screen out’ or filter irrelevant stimulus features, and (c) to scan the perceptual field for relevant stimulus features, indicated that only filtering was consistently poor in schizophrenia. It has been suggested that the schizophrenic patient may tend to perceive his environment in an undifferentiated holistic manner rather than in an analytic manner and the implication for the theory of left hemisphere pathology in schizophrenia is discussed. However, the performance of the schizophrenic subjects did not differ significantly from that of the group of depressed patients, which suggests that the selective attention deficits previously observed in schizophrenia are not specific to the disorder.