The effect of the preceding masking noise on monaural and binaural release from masking

Abstract

Auditory stream segregation can be facilitated when the maskers share coherent amplitude modulations or by utilizing spatial cues. The effectiveness of each cue can be quantified as a decrease in masked thresholds, termed as comodulated masking release (CMR) and binaural masking level difference (BMLD). Prolonged exposure to the masker can influence following target segregation. However, the collective impact preceding noise on target segregation in the presence of comodulation and interaural phase difference (IPD) cues is unclear. Stimuli were used to induce noise streams by altering the duration and temporal coherence of the envelope of the preceding masker. The effect on following target detection with CMR and BMLD induced by an IPD of the target tone was investigated. The results indicate that the effect of the preceding stream formation on CMR operates on different time scales, extending beyond 200 ms, depending on the spectrotemporal characteristics of the maskers. However, the effect on IPD-induced BMLD was not significant across time. Under the simplifying assumption that peripheral processing operates on shorter time scales than cortical processing, the results of the present study may provide insights into auditory signal processing in the presence of beneficial cues for target stream segregation.