Minimal time interval in auditory temporal resolution

Human auditory temporal resolution was measured. Normal-hearing adults in 3 age groups (I: mn age: 24 yrs, N:55; II: mn age: 44.5 yrs, N: 25; III: mn age: 66.4 yrs, N:18) were required to indicate in which of 2 successive noise bursts of relatively low frequency (concentrated from .1-.5 kc/s) a brief temporal gap was inserted. The noise was created by passing a 100-c/s square wave through an electronic switch with virtually instantaneous rise-fall time and through a clinical audiometer to the associated earphone. The level was set at about the loudness of each S's HTL at .25 kc/s. The minimum detectable time interval (delta t) varied lawfully and significantly (p less than .001) with burst duration and with age. For all ages delta t was approximately equal to 3 msec when the burst duration was longest (85 msec), but at the shortest duration (10 msec) it rose to 17.6, 22.2, and 29.9 msec for Grps I-III, respectively. The interaction between age and duration was also significant (p less than .001). It was suggested that establishment of delta t by this or a similar procedure could offer an important parameter for evaluation of auditory function.