2aPP1. Effects of modulator phase for comodulation masking release and modulation detection interference tasks.

Session: Tuesday Morning, May 14

Time: 8:35

Author: Virginia M. Richards
Author: Emily Buss
Location: Dept. of Psych., Univ. of Pennsylvania, 3815 Walnut St., Philadelphia, PA 19104


Three experiments evaluated the joint effects of target/masker frequency separation and modulator phase on modulation detection interference (MDI) and comodulation masking release (CMR). The tasks were (a) detection of the sinusoidal amplitude modulation (SAM) of a tone, (b) discrimination of changes in modulation depth of a SAM tone, and (c) detection of a tone added to a narrow band of noise. Thresholds were obtained for either the target alone, or the target presented with two maskers. The target frequency was 1500 Hz. The maskers were above and below the target at frequency separations ranging from 1/3 to 2 oct. The maskers were either tones or maskers appropriate for the task (SAM tones or noise). For nontonal maskers, the masker envelopes were either coherent or random with respect to the envelope at the target frequency. Substantial individual differences were obtained. When the tonal maskers led to only modest masking, effects of target/masker envelope randomization tended to occur for frequency separations less than an octave. The results suggest a dependence on interactions within a single, relatively broadband analyzer. [Work supported by NIH and Univ. Penn. Research Foundation.]

from ASA 131st Meeting, Indianapolis, May 1996