Molecular analysis of the effect of onset asynchrony in the identification of a rudimentary sound source in noise.
Robert A. Lutfi, Ching-Ju Liu, Christophe N. J. Stoelinga · The Journal of the Acoustical Society of America · 2010
The threshold for detecting a target in noise is often greater when the target is gated on simultaneously with the noise than when it is gated on after some delay [Zwicker, E. (1965). J. Acoust. Soc. Am. 37, 653–663]. One explanation is that the perceptual principle of grouping causes the target and noise with simultaneous onsets to be perceived as a single sound source. This idea was tested for a rudimentary sound source using perturbation analysis. In a two-interval, forced-choice procedure listeners identified as target the impact sound produced by the larger of two stretched membranes. The noise on each presentation was the impact sound of a variable-sized plate. Grouping predicts that the decision weights on the noise should be positive when target and noise have simultaneous onsets, but that they should approach zero when target and noise are gated on asynchronously. This prediction was confirmed when the noise preceded the target by a fixed interval (100 ms), but not when it followed the target by the same interval or when either interval was selected at random on each presentation (100 or −100). [Research supported by NIDCD Grant 5R01DC006875-05.]