Frequency and intensity effects on ear dominance for tone bursts

Normal-hearing Ss (N = 20) listened to dichotic pairs of 20-msec tones at 0.4, 1.5, or 3 kc/s differing by 76, 224, or 376 c/s between the two ears and also differing by 0, 15, or 35 db in SPL (the more intense tone always at 80 db SPL). S judged each pair "high-low" or "low-high" in pitch. Earlier investigations have shown that many normal-hearing Ss demonstrate a dominance for pitch perception of one ear over the other which is unaltered by large interaural intensity differences. In this study, ear dominance could be modified by a change in frequency location or interaural frequency difference of the dichotic stimuli. The effect of interaural level differences could be seen at all frequency conditions, but was strongest at low frequencies. It was suggested that ear dominance on this perceptual task is governed by several characteristics of the auditory system, including loudness perception, dichotic fusion, and frequency selectivity, as well as some as-yet ill-defined binaural processes.