Sample discrimination of target-tone duration with variable-duration context tones

Abstract

This study examined the ability of three normal-hearing listeners to discriminate duration differences in target tones with and without variable-duration context tones in frequency regions remote from the target. Single target tones at 500 (‘‘low’’), 1260 (‘‘middle’’), or 3176 Hz (‘‘high’’) were combined with one or two context tones in nontarget regions (e.g., a low target paired with a high context). Across intervals in the 2AFC task, the target tone was drawn from Gaussian distributions having a mean duration of 100 or 120 ms. Listeners were to select the target drawn from the distribution with the longer mean duration. Context-tone duration was sampled from this ‘‘correct’’ distribution, so duration alone did not cue the targets. Overall performance and perceptual weights for individual tones were examined. Frequency had no effect on performance for targets alone, however, there were interactive effects of target and context frequency. The worst performance was observed for middle targets with flanking context tones. Flanking context tones were effective in combination, but relatively ineffective individually. For low and high targets, the context tone nearer the target frequency was most effective, but both influenced performance. Comparisons to similar conditions with frequency sample discrimination will be discussed. [Work supported by NIH.]