Restarting the adapted binaural system in a background of noise

Abstract

The rate‐dependent reduced binaural sensitivity to interaural information coming after the stimulus onset has been called “binaural adaptation.” It has been shown that an appropriate restarting trigger presented during the ongoing stimulus can end the adaptation, allowing for lateralization based on information beyond the restart. Effective triggers include short bursts of noise and gaps in the stimulus. It has been reasoned that continuous spectral changes might constantly restart the system and thus preclude adaptation. To test this, click trains have been presented for lateralization in a continuous background noise and with click rates sufficiently high to produce adaptation in the quiet. Our hypothesis was wrong. While binaural thresholds increased with noise level as the noise spectrum levels rose from 0 to 20 dB, no change was observed between the forms of the functions obtained in quiet and in noise. Similarly, the inclusion of a gap in the center of the train triggered a restart both in the quiet and in the noise background. Thus a spread of energy into quiet bands as has been postulated in the past as an explanation for restarting is insufficient.