Context-Dependent Effect of Reverberation on Material Perception from Impact Sound.

Our hearing is usually robust against reverberation. This study asked how such robustness to daily sound is realized, and what kinds of acoustic cues contribute to the robustness. We focused on the perception of materials based on impact sounds, which is a common daily experience, and for which the responsible acoustic features have already been identified in the absence of reverberation. In our experiment, we instructed the participants to identify materials from impact sounds with and without reverberation. The imposition of reverberation did not alter the average responses across participants to perceived materials. However, an analysis of each participant revealed the significant effect of reverberation with response patterns varying among participants. The effect depended on the context of the stimulus presentation, namely it was smaller for a constant reverberation than when the reverberation varied presentation by presentation. The context modified the relative contribution of the spectral features of the sounds to material identification, while no consistent change across participants was observed as regards the temporal features. Although the detailed results varied greatly among the participants, these results suggest that a mechanism exists in the auditory system that compensates for reverberation based on adaptation to the spectral features of reverberant sound.