Forward masker cueing effects on backward masking

Abstract

The interactions of monaural backward and forward masking were examined to determine if a weak forward masker could serve as a timing cue to counteract a more intense backward masker. Employing an adaptive up-down procedure, the duration and intensity of the forward masker were manipulated for two different interstimulus intervals. At forward masker durations of 200, 50, and 10 ms, masker intensity was varied in 10 dB steps from 40 to 80 dBA. The signal was a 10 ms segment of a 2000-Hz sinusoid. The backward masker duration was held constant at 500 ms. The data indicate substantial reductions in backward masking as a function of the duration and intensity of the forward masker. Independent of the backward masker parameters, the greatest reductions in backward masking occurred with low intensity, long duration forward maskers. For weaker intensity maskers in isolation, significantly more backward than forward masking was obtained; with these weakest maskers in combination, backward masking was nearly eliminated, with the total amount of masking approximately equal to that obtained for the forward masker alone. The implications of these findings are discussed. [Research supported by grant NS 10995 from NINCDS.]