Effects of temporal position on the detectability of interaurally uncorrelated noise

Listeners' ability to detect an interaurally uncorrelated segment of noise within binaural broadband noise bursts was measured as a function of the temporal position of the uncorrelated noise. Psychometric functions were obtained by varying the duration of uncorrelated noise. The results indicate that detectability improves as the duration of uncorrelated noise is increased. Temporal position affected detectability only at the shortest durations of uncorrelated noise tested; a segment positioned either at the end or at the beginning of the burst is more detectable than one in the middle. This result is not easily accounted for by models of binaural processing. For example, the EC model [N. I. Durlach, J. Acoust. Soc. Am. 35, 1206–1218 (1963)] assumes that performance is determined by the power of the difference in the waveforms in the two auditory channels. Since power is computed over the total stimulus duration, it is independent of the temporal position of the uncorrelated noise. The relationship of the current findings to those for the discriminability of diotic noise stimuli will be discussed. [Work supported by AFOSR.]