ABSTRACT
An approach which views schizophrenia as a disturbance of information processing appears promising as a way of linking biological and social aspects of the disorder. There are, however, a number of difficulties associated with research into schizophrenics’ abnormalities of perception and cognition. First, a variety of models of normal cognitive functioning have been employed. Second, schizophrenics perform poorly on most cognitive tasks. Third, the studies are difficult to relate to biological abnormalities, and to possible animal models of the disorder. A review of research in this area led to the suggestion (Hemsley, 1987) that the basic disturbance in schizophrenia is “a weakening of the influences of stored memories of regularities of previous input on current perception”. This formulation leads to the prediction that in certain circumstances, schizophrenics may perform better than normal subjects. In addition it may be related to recent studies of selective attention in animals, and abnormalities resulting either from the administration of amphetamine or hippocampal lesions. Thus, a link between information processing disturbances and biological abnormalities may be possible. Three experimental studies which provide evidence in favour of the basic formulation are presented. Of the paradigms employed, two are derived from animal learning theory (latent inhibition and Kamin’s blocking effect) and the third from human experimental psychology. In all three, the pattern of performance of acute schizophrenics was consistent with the model. The ways in which such an information processing disturbance may lead to schizophrenic symptomatology are outlined, with particular reference to the formation and maintenance of delusional beliefs. Recent studies suggest an abnormal reasoning style in some deluded subjects, in addition to well established perceptual disturbances.
