The Effect of Auditory Stimulus Intensity on the Reaction Time of Schizophrenics

Experiments carried out gave further evidence for the appearance in schizophrenics of paradoxical increase in reaction time with increase in auditory stimulus intensity, and with visual stimuli, the difference of results between the two sensory modalities is discussed.

Abstract

Two earlier studies (Venables and Tizard, 1956a, b) on the reaction time (RT) of schizophrenics have shown that as the intensity of a visual stimulus is increased beyond an optimum point, RT to the stimulus increases. This “paradoxical” increase in RT is not shown by normal subjects, whose RT decreases as the intensity of visual stimulus increases. It was also found that the paradoxical phenomenon with visual stimuli was only shown on an initial occasion of testing. When the experiment was repeated twenty-four hours later, although there was no alteration in the mean level of RT, the pattern of increase in RT with increasing intensity, previously found, was absent.