Effect of Noise Crosscorrelation on Binaural Signal Detection

Abstract

The effects of varying the crosscorrelation of a noise masker upon the detection of a 500‐cps tonal signal were investigated. The correlation was varied by introducing a time delay into the channel to one ear. Ten delays yielding various positive and negative correlations and nine delays yielding zero correlations were employed with in‐phase and reversed‐in‐phase signals. A two‐interval forced‐choice procedure was used to obtain MLD's relative to the diotic condition. The function relating MLD's to delay is periodic, the largest values occurring for the antiphasic conditions and the smallest for the homophasic. The function for zero correlations is not periodic, but decreases regularly to a value near that found for uncorrelated noise. No difference is apparent between the two conditions of signal phase for zero correlations. The temporal interval over which the binaural system is able to effect a correlation between events occurring at the two ears is estimated to be at least 9 msec.