ASA 128th Meeting - Austin, Texas - 1994 Nov 28 .. Dec 02

2pPP5. Individual differences in sensitivity to interaural disparities of time and of level.

Ted L. Langford

U.S. Army Aeromed. Res. Lab., Fort Rucker, AL 36362

The sensitivities of 22 women and 23 men to interaural temporal differences (ITDs) in low-frequency noise bursts and interaural level differences (ILDs) in high-frequency noise bursts were measured in discrimination and absolute judgment tasks. The discrimination abilities of both groups of observers were symmetrical in that there were no differences in performance between interaural disparities favoring either the right or the left ear. The women were somewhat less sensitive and more variable in their performances than were the men in both the temporal and level difference discrimination tasks. However, the mean differences between the sexes, 28 (mu)s and 0.9 dB, were not large compared with the variability across individuals. Individuals who performed well-discriminating ILDs also performed well with ITDs. Many observers exhibited ILD subjective midlines which were offset to the left of objective center in the absolute judgement task. This effect was unrelated to ILD discrimination ability, to monaural thresholds, or to absolute judgements based on ITDs.