The normalized correlation: accounting for binaural detection across center frequency

Abstract

Bernstein and Trahiotis [L. R. Bernstein and C. Trahiotis, J. Acoust. Soc. Am. 100, 1754-1763 (1996)] recently reported the results of experiments designed to determine the form of interaural correlation that accounts for listeners' sensitivities to interaural disparities within high-frequency stimuli. Overall, those results demonstrated that listeners' abilities to discriminate changes in the interaural correlation of the envelope (from a base correlation of 1.0) were well accounted for by the use of the normalized correlation. The purpose of this study was to determine how well the normalized correlation computed subsequent to half-wave rectification and low-pass filtering could account for binaural detection data at low, intermediate, and high frequencies, respectively. In a four-interval, two-alternative task, listeners detected which interval contained a tone (between 500 Hz and 2 kHz) added antiphasically to diotic, 100-Hz-wide, noise (NoS pi). "Nonsignal" intervals contained the tone added homophasically (NoSo). Performance was measured for signal-to-noise ratios between -30 and +30 dB. Results indicated that a low-pass filter function based on physiological measures of synchrony in cochlear nerve fibers in conjunction with the assumption of half-wave, square-law rectification, accounted for typically 80% of the variance in the behavioral data.