LATERALIZATION OF LARGE INTERAURAL DELAYS

Two experiments explored the limits of listeners' abilities to interpr et large interaural time delays (ITDs) in terms of laterality. In expe riment 1, just-noticeable differences (jnd's) were measured, using an adaptive procedure, for various reference ITDs of Gaussian noise betwe en 0 and 3000 mu s. The jnd's increased gradually with reference ITD f or reference ITDs between 0 mu s and 700 mu s, then rose sharply to pl ateau at much higher jnd's for the remainder of the standard ITDs test ed (1000-3000 mu s). The second experiment tested left/right discrimin ation of Gaussian noise that was interaurally delayed up to 10 000 mu s, and high-pass filtered to cutoff frequencies between 0 Hz (broadban d) and 3000 Hz. There was good discrimination (62%; significantly abov e chance, p <0.05) for broadband and 500-Hz high-pass cutoff stimuli f or all ITDs up to 10 000 mu s, and for ITDs up to at least 3000 mu s f or higher high-pass cutoff frequencies. These results indicate that la terality cues are discriminable at much larger ITDs than are experienc ed in free-field listening, even in the absence of energy below 3 kHz. (C) 1998 Acoustical Society of America. [S0001-4966(98)02709-X]