ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

2pPP10. Difference limens for roved glides.

John P. Madden

Dept. of Commun. Disorders, Univ. of North Dakota, University Station, Grand Forks, ND 58202-8040

The study determined glide difference limens (GDLs) for up-glides in several conditions and estimated how well a level-detection model of the auditory periphery could account for the data. Signal durations were 50, 100, and 200 ms, and the average stimulus center frequencies were 1 and 4 kHz. To avoid the confounding effect of between-stimuli static pitch cues, the center frequencies of the standard and target stimuli were ``roved'' about the center frequencies [Neill and Feth, J. Acoust. Soc. Am. Suppl. 1 87, S23 (1990)]. The standard signals increased in frequency by 0, 200, and 400 Hz. The subject's task was to distinguish between the standard and a target signal with a greater increase in frequency in a 2-alternative, forced-choice task. The increase in the target signal was varied adaptively until discrimination threshold was obtained. The results for the 0-Hz standard were consistent with previous findings that the change in Hz at threshold is constant across duration in a glide-detection task. The results for the 200 and 400 Hz standards extend this finding to a glide-discrimination task. The modeling results suggest that the auditory system tracks gliding signals by monitoring the change in level of the output of the auditory filters. [Work supported by NIDCD.]