Dual-task performance operating characteristics, resource limitations, and automatic processing in schizophrenia

Performance on a multiple-frame search task (MFST) was investigated in 18 schizophrenia patients and 19 nonpsychiatric controls. Three of 4 indices indicated automation of visual detection responses in both groups on the MFST. In dual-task conditions (MFST during reaction time tasks), the schizophrenia patients showed greater dual-task RT slowing than controls, suggesting reduced resource availability in schizophrenia patients. Performance operating characteristic representations also indicated greater resource limitations in schizophrenia patients but showed similar allocation policy in both groups. The results suggest that schizophrenia patients have reduced availability of processing resources, which is not likely to be due to faulty resource allocation. However, these data do not confidently resolve whether schizophrenia patients reach a normal level of automation. Implications for frontal-subcortical models of schizophrenia are discussed.