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.]