Auditory objects of attention: the role of interaural time differences.

The role of interaural time difference (ITD) in perceptual grouping and selective attention was explored in 3 experiments. Experiment 1 showed that listeners can use small differences in ITD between 2 sentences to say which of 2 short, constant target words was part of the attended sentence, in the absence of talker or fundamental frequency differences. Experiments 2 and 3 showed that listeners do not explicitly track components that share a common ITD. Their inability to segregate a harmonic from a target vowel by a difference in ITD was not substantially changed by the vowel being placed in a sentence context, where the sentence shared the same ITD as the rest of the vowel. The results indicate that in following a particular auditory sound source over time, listeners attend to perceived auditory objects at particular azimuthal positions rather than attend explicitly to those frequency components that share a common ITD.