Streaming and sound localization with a preceding distractor.

Localization of a 2-ms click target was previously shown to be influenced by a preceding identical distractor for inter-click-intervals up to 400 ms [Kopčo, Best, and Shinn-Cunningham (2007). J. Acoust. Soc. Am. 121, 420-432]. Here, two experiments examined whether perceptual organization plays a role in this effect. In the experiments, the distractor was designed either to be grouped with the target (a single-click distractor) or to be processed in a separate stream (an 8-click train). The two distractors affected performance differently, both in terms of bias and variance, suggesting that grouping and streaming play a role in localization in multisource environments.