ASA 125th Meeting Ottawa 1993 May

3aMU1. Modulation detection interference and sound source determination.

William A. Yost

Stanley Sheft

Parmly Hearing Inst., Loyola Univ. of Chicago, 6255 N. Sheridan Rd., Chicago, IL 60626

This paper will review work on modulation detection interference (MDI), especially in regard to its relationship to sound source determination. MDI represents the difficulty in processing temporal modulation of a probe stimulus when one or more spectrally remote maskers are similarly modulated. Some authors have argued that MDI is an example of cross-spectral processing and is a consequence of the auditory system using coherent modulation of spectrally disparate components as an aid in sound source determination. The evidence for and against these two arguments will be provided. Data from experiments involving complex modulation patterns and multiple maskers will be described along with those from previous work involving simple modulation of a single masker. Attempts to demonstrate that MDI is primarily a cross-spectral phenomenon and that it is related to sound source determination will be made. [Work funded by grants from the NIDCD, NSF, and the AFOSR.]