An Auditory Periphery Model of Contextual Sound Lateralization with Interaural Level Differences
* Presenting author
Abstract:
The perceived azimuth of a target sound is known to depend on the azimuth of a preceding sound (precursor). Specifically, a target presented in some azimuthal proximity of a precursor is typically perceived away from the precursor. The current study characterized the precursor effect (PE) based on interaural level differences (ILDs) for high-frequency stimuli. Five normal-hearing listeners indicated the perceived azimuth of targets (from left to right) via head turn in a virtual audio-visual environment, either in isolation or following diotic, left- or right-sided precursors. Experiment 1 used noise stimuli and showed that the perceived target azimuth is shifted away from midline for contralateral and diotic precursors and towards midline for ipsilateral precursors. Experiment 2 used transposed noise stimuli with either same or different temporal pitch (one octave) of target and precursor, to study the role of their perceptual segregation. The PE persisted irrespective of the availability of the pitch cue, indicating that it operates independent of object formation. A model of the auditory periphery up to the auditory nerve, incorporating efferent cochlear compression control, predicted the general effects. Overall, at least some basic aspects of the ILD-based PE appear to arise already at the level of the auditory nerve.