Precedence effect in interaural time difference (IATD) and interaural cross correlation (IACC) perception

Abstract

A series of experiments is performed to investigate the degree of perceptual dominance of dichotic information presented in the initial part of a brief stimulus. Two types of dichotic information, interaural time difference (IATD) and interaural cross correlation (IACC), are considered separately. The experimental approach rests on the principle of estimating the overall sensation of a brief stimulus (20-ms broadband noise) in which the relevant information (IATD or IACC) in the leading part of the stimulus is opposite to that in the trailing part. The “physical” weight of the two parts of the stimulus is manipulated by two parameters: the ratio of the durations of the leading and trailing part (T1/T1, with T1 + T1 = 20 ms) and the ratio of the intensities (I1/I1). In case of equal physical weight (T1 = T1 and I1 = I1), a precedence effect is manifest for both IATD and IACC. The condition for equal subjective weight for the present 20-ms stimuli is well described by the relation 1.5I0.31 T1 = I0.31 T1.