title: Evidence specifically favoring the equalization-cancellation theory of binaural unmasking.
abstract: Three experiments investigated the roles of interaural correlation (rho) and of the monaural power spectrum in the detection and discrimination of narrow-band-noise signals (462-539 Hz) in broadband maskers (0-3 kHz). The power and rho of the target band were independently controlled, while the flanking noise was fixed and diotic. Experiments 1 and 2 involved rho and power values that would be produced by specific values of signal-to-noise ratio (SNR) in the NoSpi binaural configuration. Listeners were required to discriminate different SNRs via a 2I-FC loudness-discrimination task. At low reference SNRs, changes in rho fully accounted for listeners' performance, but as reference SNR increased, additional energy in the target band played an increasing role. Experiment 2 showed that at these higher SNRs the combination of information from the power spectrum and rho was superadditive and could not be explained by simple signal-detection models. The equalization-cancellation (EC) theory would explain these data using the output from interaural cancellation, Y, rather than rho. Experiment 3 attempted to foil binaural processing, by fixing either rho or Y across intervals. Consistent with EC theory, when Y was fixed, the contribution of the binaural system appeared negligible, while fixing rho did not have this effect.
authors.affiliation: School of Psychology, Cardiff University, Tower Building, Park Place Cardiff, CF10 3AT, United Kingdom. cullingj@cf.ac.uk
authors.forename: John F
authors.initials: JF
authors.lastname: Culling
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D001309:Auditory Threshold; D004192:Discrimination, Psychological; D006801:Humans; D008144:Loudness Perception; D008297:Male; D008960:Models, Psychological; D009622:Noise; D010470:Perceptual Masking; D011571:Psychoacoustics