Detectability of a pulsed tone in the presence of a masker with time‐varying interaural correlation

Detectability of a filtered 4‐ms tone burst (500 or 1000 Hz), presented binaurally and phase reversed (Sπ), was measured in the presence of a narrow‐band Gaussian noise masker whose interaural correlation varied sinusoidally between +1.0 (N0) and −1.0 (Nπ). Independent variables were the rate of modulation of the masker correlation (fm), and the instantaneous interaural correlation of the masker when the signal was presented. The peak masking‐level difference (signal threshold in Nπ versus threshold in N0) was as large as 17 dB with the 500‐Hz signal and fm < 1 Hz. The peak MLD with the 1000‐Hz signal was smaller (8 dB). No MLD could be obtained with fm > 10 Hz. The function relating the MLD to fm, describes a kind of “attenuation characteristic” of the binaural system. Our data agree with the growing body of evidence that the binaural system is extremely sluggish in responding to dynamic stimuli. Furthermore, in terms of its response to dynamic stimuli, the binaural system appears to behave similarly in the different spectral regions tested.