An early cue sometimes impairs process schizophrenic performance

Abstract

BACKGROUND The simple reaction time task THE SIMPLE reaction time task is well known for its sensitivity to schizophrenic pathology. The precision of the procedure, the replicability of results, and the salience for theorizing about the nature of attentional deficits in schizophrenic pathology have made it a virtual “north star” of schizophrenia research.1 In its basic form the task has three primary stimulus features comprised of two signals with a delay interval between. The first signal is an alerting or “ready” signal designed to announce the beginning of each trial. Following that signal there is a delay of preparatory interval during which the subject has been asked to wait vigilantly for the second stimulus which serves as a signal-to-respond. The response is generally a finger lift or a retraction from a telegraph key. These task features have been studied to learn how procedural variation interacts with schizophrenic pathology. The latency of response, recorded in milliseconds, is generally used to assess experimental and subject variation. Maximum attention has been given in the literature to the study of two of these features. The signal-to-respond or imperative signal has been investigated in terms of the intensity,2 the modality,3 and the modality relationship among trials.4 The delay interval, or preparatory interval, has been investigated in relation to the length of the delay and the predictability of the various delays used across trials. 5 Studies of these two features have provided support for various theoretical constructions of schizophrenic pathology, for example, SHAKOW~ and ZUBIN.6.