  There is increasing evidence that people with hallucinations overweight
perceptual beliefs relative to incoming sensory evidence. Much past work
demonstrating prior overweighting has used simple, non-linguistic stimuli.
However, auditory hallucinations in psychosis are often complex and linguistic.
There may be an interaction between the type of auditory information being
processed and its perceived quality in engendering hallucinations. We
administered a linguistic version of the Conditioned Hallucinations (CH) task
to an online sample of 88 general population participants. Metrics related to
hallucination-proneness, recent auditory hallucinations, stimulus thresholds,
and stimulus detection were collected; data was used to fit parameters of a
Hierarchical Gaussian Filter model of perceptual inference to determine how
latent perceptual states influenced task behavior. Replicating past results,
higher CH rates were associated with measures of higher hallucination-proneness
and recent hallucinatory experiences; CH rates were positively correlated with
increased prior weighting; and increased prior weighting was related to recent
hallucinatory experiences. Unlike past results, participants with recent
hallucinatory experiences as well as those with higher hallucination-proneness
had higher stimulus thresholds, lower sensitivity to stimuli presented at the
highest threshold, and tended to have lower response confidence, consistent
with lower precision of sensory evidence. We show that hallucination-prone
individuals in the general population have increased conditioned hallucination
rates using a linguistic version of the CH task, and replicated the finding
that increased CH rates and recent hallucinations correlate with increased
prior weighting. Results support a role for reduced sensory precision in the
interplay between prior weighting and hallucination-proneness. *contributed
equally
