Rubber voice illusion exposed neural correlates of voice perception and vocal adaptation across the continuum of psychosis

The Rubber Voice Illusion, an auditory analogue of the Rubber Hand Illusion, causes speakers to momentarily adopt a stranger’s time-locked voice as self-generated. In 60 healthy adults, only the congruent stranger voice evoked a sense of Ownership and Agency, along with an upward pitch shift toward the stranger’s voice, indicating voice adaptation. Neurophysiologically, speaking-induced suppression was replicated and was significantly smaller in participants scoring high on the Peters et al. Delusions Inventory. In controls, greater pitch shift correlated with stronger neural suppression, suggesting a functioning self-suppression mechanism; in high-schizotypy individuals, the relationship reversed, showing reduced suppression despite pitch shifting, indicating decoupling between motor output and sensory prediction.

Study at a glance

Abstract

The Rubber Voice Illusion is an auditory analogue of the classic Rubber Hand Illusion, a “mind-trick” for the voice. When speakers hear a stranger’s utterances that are perfectly time‑locked and syllable‑matched to their own voice, many momentarily adopt that alien voice as self‑generated. We used this illusion to probe the integrity of predictive auditory mechanisms across the psychosis continuum. Sixty healthy adults completed three Talk‑Listen conditions while high‑density EEG was recorded: veridical (live playback of own voice), stranger‑match (congruent stranger voice) and stranger‑mismatch (incongruent). Behaviorally, only the congruent condition evoked a sense of Ownership and Agency over the stranger’s voice, paired with an upward shift in fundamental frequency toward the higher-pitched stranger voice - an implicit indication of voice adaptation. Neurophysiologically, the canonical speaking-induced suppression was replicated, and suppression was significantly smaller in participants who scored high on Peters et al. Delusions Inventory. In controls, greater pitch shift was associated with stronger neural suppression, suggesting a functioning self-suppression mechanism; conversely, in high-schizotypy individuals, the relationship reversed, despite pitch shifting toward the stranger’s pitch, they exhibited reduced suppression, indicating decoupling between motor output and sensory prediction. The study provides further evidence to the intricate relationship of neural mechanisms underlying self-generated actions with sensory processing in the psychosis continuum.