Content area
Abstract
Reaction time (RT) crossover is a well established measure of attentional deficit in schizophrenia. This measure has been found to discriminate between chronic schizophrenic and normal groups, is independent of the intellectual deterioration commonly observed in schizophrenics, does not result from the increased RT latency of persons who are actively psychotic, is predictive of prognosis and chronicity rather than clinical state, and is thought to be a marker of vulnerability to schizophrenia. Two competing theories have been developed which identify specific attentional anomalies said to result in RT crossover, but the theories are each supported by studies using differing experimental procedures. This study articulates a unifying theory and integrates the procedures. The present study does not replicate the group differences in RT crossover observed in previous studies. It is suggested that the counterbalancing of prepreparatory intervals (PPIs) incorporated in this study eliminates RT crossover, that RT crossover is an artifact of PPI effects, and that direct measurement of PPI effects may be useful in future psychopathology research.
