Rate of information processing in a schizophrenic and a control group: the effect of increasing task complexity.

Abstract

In recent years two cognitive models of schizophrenic dysfunction have been elaborated which involve the basic proposition that schizophrenic patients process information at a slower rate than non‐schizophrenic controls (McGhie, 1965; Yates, 1966). Both models predict (1) that schizophrenic patients will make decisions at a slower rate than controls at all levels of task complexity, and (2) that their relative slowness will increase as a function of increasing task complexity. The available evidence is consistent with the first prediction but ambiguous with respect to the second.All previous studies relating to the above issues have utilized discrete reaction time measures. It was hypothesized that a more sensitive test of the predictions would be provided by a continuous performance task involving responding over a longer time period. A study is reported in which a group of chronic schizophrenic patients was compared with a group of non‐schizophrenic control patients on a series of four card‐sorting tasks in which the ‘information to be processed’ was systematically varied. In general, the findings were consistent with expectations.