ABSTRACT
Previous studies on the precedence effect (e.g., Zurek, JASA 67, 952–964 [1980]) demonstrated that a brief diotic sound, called the conditioner, suppressed its spatially displaced “echo”, i.e., a brief dichotic probe presented a few ms later, when the spectral composition of both stimuli was identical. In our experiments we used various unfiltered and filtered (high-pass, low-pass, band-pass, and band-reject) brief sounds (noise bursts and clicks) for the conditioner and the probe. Suppression of the probe was seen in all conditions where the conditioner and the probe were identical in their spectra, but coherence between conditioner and probe waveforms was not required in order for echo suppression to occur. Some suppression was also seen when the probe had its energy concentrated in regions above the spectrum of the conditioner. On the other hand no suppression was seen for probes with spectra below the conditioner. Our findings indicate that echo suppression may occur whenever we can infer a significant overlap between the monaural excitation patterns generated by the conditioner and the probe, suggesting that binaural interaction is subsequent to, and may be based on, monaural frequency analysis.
