Cognitive deficit in schizophrenia. Subvocal mediation, rigidity, and complexity parameters.

This study investigated the effects of problem complexity on cognitive performance of 96 schizophrenic and nonpsychiatric inpatients. Subvocal activity (mediation) and three rigidity parameters were examined in relation to performance. The major findings were: a) with increased problem complexity, schizophrenics demonstrated relatively greater difficulty in performance than controls; b) subvocal activity was greater in schizophrenics than controls and was positively related to both the complexity of the problem and the inability to respond correctly; c) motor-cognitive rigidity was higher in schizophrenics and positively correlated with cognitive errors, as well as with the subvocal activity--this was not so in controls, demonstrating the differential role of the rigidity dimension in the two populations.