ASA 127th Meeting M.I.T. 1994 June 6-10

3pPP7. Observer weighting of concurrent binaural information.

M. A. Stellmack

Waisman Ctr., Univ. of Wisconsin, 1500 Highland Ave., Madison, WI 53706

Robert A. Lutfi

Univ. of Wisconsin, Madison, WI 53706

On each experimental trial, a two-component complex consisting of a 553- and 753-Hz pure tone was presented to listeners over headphones. Each component had an interaural delay that was independently and randomly chosen on each presentation from a single uniform distribution ranging from -100--100 (mu)s. In different conditions, listeners were instructed to make a left--right judgment indicating the lateral position of the 753-Hz component relative to center, the 553-Hz component relative to center, the total signal relative to center, or the 753-Hz component relative to the 553-Hz component. The observer weights for each component and an estimate of internal noise were derived by computing the correlations between the interaural delays of the components and the listeners' left--right judgments. Three of the four listeners were found to adjust their weights appropriately for each listening task, while the fourth listener consistently gave almost no weight to the 553-Hz component regardless of the listening condition. Estimates of internal noise were largely unchanged across listening conditions for all listeners. [Research supported by NIDCD.]