Lateralization of an Auditory Signal in Correlated Noise and in Uncorrelated Noise as a Function of Signal Frequency

Abstract

Listeners lateralized a monaural signal presented against a continuous background of perfectly correlated noise (NO) and of uncorrelated noise (NU). Measures of signal detection were also secured in separate tests. Psychometric functions (percent correct versus signal energy) were determined for each task. For a tonal signal of either low or high frequency, the listener requires only slightly greater signal energy (1–2 dB) in order to lateralize as well as he can detect when the noise is uncorrelated (NU). When the noise is perfectly correlated (NO), the slope of the psychometric function for lateralization depends upon signal frequency. With 250 cps, the slope of the function for lateralization is much smaller than that for detection. With 1000 cps, the function for lateralization is steeper than that for 250, but the slope is still less than that for the function for detection of 1000. With 2000 cps, the function has about the same slope as that for detection. [Research supported by U. S. Air Force Office of Scientific Research.]