Effects of expectations and sensory unreliability on voice detection - A preregistered study.

Hearing voices is not limited to psychotic disorders but also occurs in the general population, often as perceptions of supernatural beings. In a preregistered experiment, participants completed a signal detection task where expectations about the number of voices present influenced their response bias: expecting fewer voices led to a more conservative strategy, while expecting more led to a more liberal one. Adding sensory noise amplified these effects. The findings indicate that voice detection relies on expectations, especially when sensory data are unreliable, shedding light on predictive processes underlying voice-hearing experiences.

Study at a glance

Abstract

The phenomenon of "hearing voices" can be found not only in psychotic disorders, but also in the general population, with individuals across cultures reporting auditory perceptions of supernatural beings. In our preregistered study, we investigated a possible mechanism of such experiences, grounded in the predictive processing model of agency detection. We predicted that in a signal detection task, expecting less or more voices than actually present would drive the response bias toward a more conservative and liberal response strategy, respectively. Moreover, we hypothesized that including sensory noise would enhance these expectancy effects. In line with our predictions, the findings show that detection of voices relies on expectations and that this effect is especially pronounced in the case of unreliable sensory data. As such, the study contributes to our understanding of the predictive processes in hearing and the building blocks of voice hearing experiences.