Localization in noise and the role of forward masker fringe.

Abstract

Previous research suggests that the localization of a target sound in a masking noise is more accurate when the masker is preceded by a forward masker fringe. It is unclear what information listeners are exploiting to produce this improvement in performance. Does the fringe simply reduce spatial uncertainty (by cuing the location of the masker) or does it provide a “context” against which the onset of the signal is more easily discerned? In order to address these questions, we examined conditions in which the masker is (a) pulsed on and off with a 60 ms target (no fringe), (b) immediately preceded by a 500‐ms masker fringe; or (c) preceded by a 500‐ms fringe + a 500‐ms gap. Masker spatial uncertainty was also manipulated by presenting the noise from a fixed and known location throughout a block, or from a location that varied across trials. The results suggest that listeners benefit from the presence of a forward masker fringe even when the masker location is known. However, localization performance is best when this fringe occurs immediately prior to the masker (i.e., no gap), suggesting that onset‐related cues also contribute to the improvement in localization. [Work supported by the AFOSR]