Frequency-specific, location-nonspecific adaptation of interaural time difference sensitivity

Human listeners' sensitivity to interaural time differences (ITD) was assessed for 1000 Hz tone bursts (500 ms duration) preceded by trains of 500-ms "adapter" tone bursts (7 s total adapter duration, frequencies of 200, 665, 1000, or 1400 Hz) carrying random ITD, or by an equal-duration period of silence. Presentation of the adapter burst train reduced ITD sensitivity in a frequency-specific manner. The observed effect differs from previously described forms of location- specific psychophysical adaptation, as it was produced using a binaurally diffuse sequence of tone bursts (i.e., a location- nonspecific adapter stimulus). Results are discussed in the context of pre-binaural adaptation.