Short-term memory for serial order in schizophrenia: A detailed examination of error types

Cognitive deficits in schizophrenia have been associated with working memor y problems. Schizophrenic patients (n = 24) and controls (n = 29) participa ted in simple short-term memory tasks, recalling a list of letters from the first to last item in the order of presentation. The authors hypothesized that deficient sequential representations would increase movement errors (e .g.. ABCD being recalled as ABDC) or intrusion errors (e.g., ABCD being rec alled as ABCX), whereas simple trace decay would lead to omission errors (e .g., ABCD being recalled as ABC_). Patients made disproportionately more om issions toward the end of 6-item lists. There were no group differences in movements or intrusions as a function of serial position. Schizophrenic pat ients' limited short-term memory span may be due to greater forgetting duri ng recall and not to a selective deficit in the mechanisms responsible for maintaining serial order information.