Decision making in auditory externalization perception

Under natural listening conditions, humans perceptually link sounds with sound sources in their environment. This so-called auditory externalization is often distorted when sound is produced via hearing devices such as headphones or hearing aids, resulting in sources being perceptually localized inside the head. Psychoacoustic studies suggest a mixed role of various cues in the externalization process. As such, we developed a model framework able to probe the contribution of those cues and test the perceptual decision strategy of listeners performing various externalization tasks. Following previous investigations in vision, we contrasted different strategies including a static combination of cues and three dynamic selection approaches. Our results show that the decision strategy following a static combination of cues best explains externalization ratings. Further, our analysis indicates that listeners mainly base their perceptual decision on both monaural and interaural spectral shapes, whereas the contribution of other cues was not significant. The proposed model predicts auditory externalization under the most fragile condition of static listening and has the potential to significantly advance the future development of spatially-aware hearing technologies by helping to identify perceptually relevant auditory distortions.