Robotically-induced auditory-verbal hallucinations: combining self-monitoring and strong perceptual priors.

A robotic procedure that creates sensorimotor conflicts and a feeling of another person's presence can induce auditory-verbal hallucination (AVH)-like sensations in healthy individuals. In two studies, participants showed increased false alarm rates on a voice detection task. Stronger sensorimotor conflicts led to more AVH-like sensations, supporting the self-monitoring deficit account. The otherness condition produced more false alarms when detecting other-voice stimuli than self-voice stimuli, consistent with the strong perceptual priors account. The findings integrate both theoretical models of AVH.

Study at a glance

Abstract

Inducing hallucinations under controlled experimental conditions in non-hallucinating individuals represents a novel research avenue oriented toward understanding complex hallucinatory phenomena, avoiding confounds observed in patients. Auditory-verbal hallucinations (AVH) are one of the most common and distressing psychotic symptoms, whose etiology remains largely unknown. Two prominent accounts portray AVH either as a deficit in auditory-verbal self-monitoring, or as a result of overly strong perceptual priors. In order to test both theoretical models and evaluate their potential integration, we developed a robotic procedure able to induce self-monitoring perturbations (consisting of sensorimotor conflicts between poking movements and corresponding tactile feedback) and a perceptual prior associated with otherness sensations (i.e. feeling the presence of a non-existing another person). Here, in two independent studies, we show that this robotic procedure led to AVH-like phenomena in healthy individuals, quantified as an increase in false alarm rate in a voice detection task. Robotically-induced AVH-like sensations were further associated with delusional ideation and to both AVH accounts. Specifically, a condition with stronger sensorimotor conflicts induced more AVH-like sensations (self-monitoring), while, in the otherness-related experimental condition, there were more AVH-like sensations when participants were detecting other-voice stimuli, compared to detecting self-voice stimuli (strong-priors). By demonstrating an experimental procedure able to induce AVH-like sensations in non-hallucinating individuals, we shed new light on AVH phenomenology, thereby integrating self-monitoring and strong-priors accounts.