The over-estimation of distance for self-voice versus other-voice.

Self-related stimuli are important cues for people to recognize themselves in the external world and hold a special status in our perceptual system. Self-voice plays an important role in daily social communication and is also a frequent input for self-identification. Although many studies have been conducted on the acoustic features of self-voice, no research has ever examined the spatial aspect, although the spatial perception of voice is important for humans. This study proposes a novel perspective for studying self-voice. We investigated people's distance perception of their own voice when the voice was heard from an external position. Participants heard their own voice from one of four speakers located either 90 or 180 cm from their sitting position, either immediately after uttering a short vowel (i.e., active session) or hearing the replay of their own pronunciation (i.e., replay session). They were then asked to indicate which speaker they heard the voice from. Their voices were either pitch-shifted by ± 4 semitones (i.e., other-voice condition) or unaltered (i.e., self-voice condition). The results of spatial judgment showed that self-voice from the closer speakers was misattributed to that from the speakers further away at a significantly higher proportion than other-voice. This phenomenon was also observed when the participants remained silent and heard prerecorded voices. Additional structural equation modeling using participants' schizotypal scores showed that the effect of self-voice on distance perception was significantly associated with the score of delusional thoughts (Peters Delusion Inventory) and distorted body image (Perceptual Aberration Scale) in the active speaking session but not in the replay session. The findings of this study provide important insights for understanding how people process self-related stimuli when there is a small distortion and how this may be linked to the risk of psychosis.