Some effects of the saliency of the lagging stimulus on localization dominance for temporally overlapping, long-duration noise stimuli

Abstract

In reverberant spaces, human listeners localize sounds to the direction of their sources, despite room reflections that present spurious directional cues. This ability is often called localization dominance, which is part of the precedence effect. In this thesis, a series of six experiments address multiple aspects of the precedence effect using a simplied paradigm of a leading stimulus (modeling the direct sound) and a single lagging stimulus (modeling a single reflection). These experiments manipulated the relative saliency of the lagging stimulus to investigate the mechanisms involved. The effects of increased lag level (Experiment 1), different noise tokens (Experiment 2), click stimuli versus long-duration (Experiment 3), inclusion or exclusion of temporal onsets and onsets (Experiment 4), the rapidity of the onset cue (Experiment 5), stimulus duration in the absence of onset and oset cues (Experiment 5), and temporal diffusion with reduced binaural coherence of the lag (Experiment 6) were measured. A reductive model of peripheral and central auditory processing that utilized only the most salient stimulus information was then designed. The model, which incorporated several neural mechanisms that have been suggested by previous studies, was used to test and evaluate a representative sample of the stimulus conditions that were investigated in the current psychophysical experiments.