Ear dominance and intensity independence in the perception of dichotic chords.

Abstract

The perceived pitch mixture of two tones of a dichotically presented chord was studied as a function of the difference between the intensities of the right and left ear tones (ΔI). Previous experiments have shown that, within a wide range of ΔI, the pitch mixture is independent of ΔI. This intensity independence of the pitch mixture of dichotic chords is not seen with monaural chords. Within the range of ΔI over which intensity independence is seen, the pitch mixture of the dichotic chord is determined by another property of the central pitch processor—the ear dominance function. In previous experiments the intensity independent function could only be detected in those subjects with a weak ear dominance function. In the present experiments subjects adjusted the relative intensities of the two tones of a binaural chord to match the pitch mixture of a dichotic chord. Using this method, the intensity independent function was measured directly in all subjects. In addition, the present method provides a direct measure of the magnitude of the suject’s ear dominance function and clarifies the relationship between the effects of the two functions.