Abstract:
Weights that listeners placed on interaural differences of time (IDT's) were computed for two pure tones that had different mean IDT's. As a cue on each trial, the target (753 Hz) was presented in isolation at its mean IDT. Then, the target and distractor (553 Hz) were presented simultaneously with IDT's selected from Gaussian distributions ((sigma) = 50 (mu)s). The listener indicated whether the target in the test interval appeared to have moved to the left or right of its cued position. The weights were the correlations between the IDT of each component and the listener's left/right response. In one condition, the mean target and distractor IDT's were of equal magnitude (0, 25, 50, 100, and 200 (mu)s) but opposite sign. Large individual differences in weights and percent correct were observed. In a second condition, the mean target IDT was 0 (mu)s and the mean distractor IDT was 0, 50, 100, or 200 (mu)s. Here, target weights and percent correct generally increased for all listeners as the mean distractor IDT increased. Results are attributed to increased target weight as the difference between target and distractor IDT increased, and decreased sensitivity to changes in IDT as mean IDT increased. [Work supported by a Program Project Grant from NIDCD.]