Binaural ambiguity amplifies visual bias in sound source localization

Auditory spatial perception relies on more than one spatial cue. This study investigated the effects of cue congruence on auditory localization and the extent of visual bias between two binaural cues—interaural time differences (ITDs) and interaural level differences (ILDs). Interactions between these binaural cues were manipulated by stereophonic techniques. The results show that incoherent binaural information increased auditory response noise and amplified visual bias. The analysis further suggests that although ILD is not the dominant cue for low-frequency localization, it may strengthen the position estimate by combining with the dominant ITD information to minimize estimation noise.