Abstract:
Previous work has shown that the motion of an auditory signal, when simulated over earphones by presenting a binaural stimulus with a changing interaural temporal difference, does not enhance its detectability relative to that of a stationary signal [Grantham and Luethke, J. Acoust. Soc. Am. 83, 1117--1123 (1988)]. The present study will compare the detectability of stationary and moving auditory targets presented in free-field, where all cues for location, including interaural level differences and spectral information, will be available. Six normal-hearing subjects will be tested individually in a darkened anechoic chamber. Masked threshold will be determined in an adaptive, single-interval 2AFC procedure for targets that are either stationary or moving at various velocities. Three different signals will be employed: a 500-Hz tone, an 8000-Hz tone, and a broadband noise. Preliminary results from one subject indicate that motion may enhance the detectability of broadband noise targets, but not of the pure-tone targets. [Work supported by NIDCD.]