Detection of interaural phase shift between a subaudible and an audible tone.
Can a shift in interaural phase between a subthreshold signal and an audible contralateral probe tone affect perception of the probe? To obtain an answer, an 800-Hz tone was presented to both ears. The tone was presented continuously to one ear (-25 to + 10 dB SL) and in a sequence of four bursts per trial to the other ear (+ 10 dB SL). Interaural phase was reversed for either the second or the fourth burst in a 2 AFC task. Interaural phase-shift detection threshold (65% correct) varied with the intensity of the continuous signal; across subjects, this threshold varied from -21 to + 1 dB SL. When a 300-or 500-Hz masking tone was added to the ear with the continuous signal, phase-shift detection accuracy depended primarily upon the sensation level of the signal rather than its sound pressure level. These findings demonstrate temporal encoding at signal levels well below hearing threshold.
D000293:Adolescent; D000328:Adult; D001288:Attention; D001309:Auditory Threshold; D004292:Dominance, Cerebral; D006801:Humans; D008297:Male; D010470:Perceptual Masking; D010897:Pitch Discrimination; D011571:Psychoacoustics