EFFECTS OF ATTENDING TO AUDITORY SIGNALS ON THE MAGNITUDE OF THE ACOUSTIC REFLEX

In order to test the hypothesis that the acoustic reflex (AR) is inhibited while subjects listen for faint signals or while they track their threshold for a 250 Hz tone, two experiments were conducted in which the main objective was to measure the effects of attention demanding conditions on the magnitude of the AR. In the first of these, subjects were required to detect faint signals (threshold level clicks) in either phone ear or probe ear while the AR was elicited by a one second, 1500 Hz tone. The control condition consisted of merely remaining alert but not listening for a signal during the reflex elicitation. The results of this experiment did not demonstrate any significant effect of listening for faint clicks in either contralateral or homolateral ear on the magnitude of the AR. In the second experiment, subjects tracked a 250 Hz threshold level tone before and during eliciting tones of 15 seconds duration in the same ear. In the control condition, they merely remained alert during the elicitation. Results of this experiment showed the magnitude of the AR to be significantly (p < .05) larger when the subjects tracked the 250 Hz tone than when not tracking. These results do not support the notion of inhibition of the AR by subjects listening for faint sounds (Smith and Loeb, 1967). (Author)