Heart rate changes during a fixed reaction time task in normal and retarded adult males.

Abstract

ABSTRACTThe relationship between heart rate (HR) changes and fixed reaction time (RT) performance was studied in groups of normal and mentally retarded male Ss. Each 5 received blocks of 15 RT trials during 4‐, 7‐, and 13‐sec preparatory intervals. Heart rate was continuously monitored. The results revealed that retarded Ss had significantly slower RT scores, significantly lower basal HR, and lower magnitude HR decelerations prior to reaction signal onset when compared to normal Ss. These group differences were apparent in all three preparatory interval conditions and were interpreted to indicate less accurate covert timing of PI length in retarded 5s. Correlations between HR deceleration (measured during the sec in which the reaction signal occurred) and RI scores lent support to the notion that significant HR deceleration accompanies fast RT responding in all but the 13‐sec PI condition for retarded Ss. In this condition, HR acceleration was related to fast RT performance in retarded Ss. It was suggested that in the 13‐sec PI, retarded Ss exhibited a dissociation between somatic and autonomic response systems which might he related to an information processing deficit in tasks of extended duration.