Parametric study of accuracy and response time in schizophrenic persons making visual or auditory discriminations.

The inability to modulate processing time in conjunction with varying difficulty levels may be a core component of schizophrenia's cognitive deficit. In this study we used a parametric design to demonstrate this group's inability to increase and decrease response times in association with varying levels of task demand during auditory and visual recognition tasks. Unlike participants with schizophrenia, healthy volunteers responded to increasing levels of difficulty and high error by robustly increasing their average response times. In the group with schizophrenia, the greater the correlation between a subject's Response-Time and error rate the better was the subject in his/her overall discrimination accuracy. The higher their correlations the better they performed across all levels of difficulty in both modalities. The schizophrenia group's tendency to process high and low error conditions with similar behavioral resources may reflect a relatively static, non-dynamic cognitive repertoire.