Binaural detection as a function of interaural correlation and bandwidth of masking noise: implications for estimates of spectral resolution.

Detection thresholds were measured for an antiphasic (S pi) 500-Hz tone masked by a binaural noise, as a function of the bandwidth of the noise. Several values of interaural correlation of the masking noise were used, ranging from -1 to +1. The bandwidth dependence of the thresholds showed a pattern consistent with a 100-Hz-wide critical band for most values of interaural correlation, even for those values which resulted in a considerable binaural release of masking. Only when the interaural correlation of the masking noise was very close to, or equal to, unity was the bandwidth dependence of the thresholds in accord with an approximately 300-Hz-wide "binaural" critical band measured in previous studies. Our analysis of the data calls into question the commonly stated notion that binaural processing is characterized by a wider critical band than is monaural processing.