Cross-modal reaction time and schizophrenic attentional deficit: a critical review.

This article focuses on the cross-modal reaction time paradigm, which has been used to study deviation patterns of shifting attention across stimulus modalities in schizophrenic patients. Cross-modal reaction time research involving pathological and nonpathological populations is reviewed. The influence of sex, stimulus modality, total stimulus energy, the warning signal, psychotropic drugs, psychiatric diagnosis, and preparatory interval on the modality shift effect (the ability of cross-modal retardation to discriminate schizophrenic patients and normal control subjects) is discussed. Theories proffered to account for the modality shift effect are critically evaluated. These theories include Zubin's neural trace theory, the magnitude of difference hypothesis, the expectancy hypothesis, learning theory, general inattention, and psychometric artifact. The article concludes with general comments on attentional research in schizophrenia.