Correlates of Reaction Time to Startle ’.

The present study was concerned with behavioral and physiological correlates o f response time to high intensity, ‘unexpected ’ auditory stimuli. Stimuli consisted of an initial I20 db startle tone followed by a series of 50 tones of 75 db and a final 120 db startle tone. Sub-jects responded by moving a control stick as rapidly as possible to the onset of each tone. Continuous recordings of heart rate and skin resisfance were taken. Autonomic reactivity to the first intense stimulus was found to be positively correlated with response latency, while response time to the final intense stimulus suggests a negative relationship to autonomic levels and reactivity. The primary eflect of the second high intensity tone was to significantly exaggerate pre-existing differences between individuals in their reaction time to the preceding moderate intensity stimuli. Possible relationships of this diflerential stress response to concepts of excitation and inhibition are briefly discussed. The ability of an operator to recover cog-nitive-motor functioning rapidly following a sudden and unexpected emergency is obvi-ously desirable behavior. Yet, it is generall