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

4pPP2. The role of component-relative entropy in the discrimination of simultaneous tone complexes.

Dept. of Commun. Disord. and Waisman Ctr., Univ. of Wisconsin, Madison, WI 53706

Results are reported from a number of experiments investigating the effects of stimulus uncertainty on the discrimination of simultaneous multitone complexes. The results are generally consistent with the predictions of a model in which average threshold for the detection of a change in a single component is related to that component's relative entropy (CoRe) in the complex [R. A. Lutfi, J. Acoust. Soc. 94, 748--758 (1993)]. In different experiments, target thresholds are found to be linearly related to CoRE for manipulations of target level, number of targets, number of context tones, and the relative degree of level perturbation on the tones from trial to trial. In most cases, the slopes of the functions are close to the theoretical value of b=-1.0, as predicted by strict application of the model. In the few cases where the slopes deviate significantly from this value, the slopes are much smaller in absolute magnitude. Compared to studies where the model has been previously applied the estimates of slopes are also substantially smaller in absolute magnitude, |b|=1.0 versus 3.0. The difference in estimates is likely due to a difference in methodology used in these studies. [Research supported by NIDCD.]