Masking with interaurally “double-delayed” stimuli: The range of internal delays in the human brain

Is binaural processing in humans different to that of other mammals? While psychophysical data suggest that the range of internal delays necessary for processing interaural time differences is at least +/-3 ms, physiological data from small mammals indicate a more limited range. This study demonstrates that binaural detection is impeded by reduced interaural coherence in auditory channels remote from the signal frequency, in accordance with the wider critical bandwidths reported for binaural processing. This explains previous psychophysical data without requiring long internal delays. The current psychophysical data support the view that human binaural processing is similar to that of other mammals.