The reduction of binaural interference by the temporal nonoverlap of components

Threshold interaural delays were measured for a single interaurally delayed 753-Hz target component presented against a background of six diotic distractor components (453, 553, 653, 853, 953, and 1053 Hz). In one set of conditions, all components were gated on simultaneously, but 200-ms after their onset the distractors were turned off for 10, 25, 50, 100, or 200 ms, then turned on again for the remainder of the 500-ms listening interval. In a second set of conditions, the target component was present only during the temporal notch in the distractors for notch durations of 50, 100, and 200 ms. Threshold interaural delays were also measured for the target component in isolation at durations of 50, 100, 200, and 500 ms. In both sets of conditions in which the distractors were present, it was observed that a brief isolated presentation of the target reduced threshold interaural differences of time to nearly the level of thresholds for the target presented in total isolation, while thresholds were many times higher when the distractors had no temporal notch. Possible sources of binaural interference are discussed and the evidence supporting each is evaluated.