Effects of Asymmetrical Masking on the Binaural Lateralization of Clicks Free

Brief pulses, delivered binaurally to listeners wearing earphones, produce a sound image centered in the head when the pulses are identical and simultaneous. Changing the polarity of one pulse (for example, from rarefaction to condensation) changes the relative times of occurrence that produce a centered image [J. Acoust. Soc. Am. 33, 840A (1961)]. This interaural disparity appears explicable in terms of the mechanical response of the basilar membrane and simple hypotheses about mechanical‐to‐neural transduction in the ear. Similarly, the disparity can be manipulated by symmetrical HP or LP masking noise. By this means, the coherent neural information is elicited from a specific place on the membrane, and reflects the mechanical properties of that place [J. Acoust. Soc. Am. 33, 1670A (1961)]. When the masking is made asymmetrical (for example, HP in one ear, LP in the other), the interaural times can be made also to reflect the transit times to specific points on the membrane. This paper presents data for lateralizing both cophasic and antiphasic pulses under the following asymmetric masking: 600 HP vs unmasked; 2400 LP vs unmasked; 600 HP vs 2400 LP. The unmasked vs unmasked condition is included as a control. The results continue to support the hypotheses advanced in the earlier work, and the behavior appears to be explicable in terms of the displacement responses of the basilar membrane.