Auditory cue combination in perceptual externalization of static sound sources: a model-based meta analysis

Abstract Under natural conditions, listeners perceptually attribute sounds to external objects in their environment. This core function of perceptual inference is often distorted when sounds are produced via hearing devices such as headphones or hearing aids, resulting in sources being perceived unrealistically close or even inside the head. Psychoacoustic studies suggest a mixed role of various monaural and interaural cues contributing to the externalization process. We developed a model framework for perceptual externalization able to probe the contribution of cue-specific expectation errors and to contrast dynamic versus static strategies for combining those errors within static listening environments. The model was applied to various acoustic distortions with constant reverberation as tested in five previous experiments. Our results suggest that the decisions follow a static, weighted accumulation of expectation errors for both monaural and interaural spectral shapes, without a significant contribution of other auditory cues.