The researchers also noted that participants with a psychotic condition, whether it was schizophrenia or psychosis without auditory hallucinations, were less likely to notice when, at the end of the experiment, the tones became less frequent. This suggests that they had a harder time updating their belief about the correlation between the tone and the checkerboard compared than the others.
Computer modeling of the participants' brain turned out to be very revealing. Those who experienced severe hallucinations showed less activity in the cerebellum. The cerebellum is responsible for planning and coordinating future activity. Seeing as this requires being able to update your beliefs about the outside world, this fits with the rest of the experiment's findings.
This reaffirms previous research that has looked at the correlation between people’s assumptions and expectations with visual hallucinations. But what now? Larger studies and machine learning tactics can be used to help differentiate between psychotic and non-psychotic voice hearers. This means that, in future, researchers may be able to detect if people experiencing hallucinations are heading towards psychosis and, if they do, be able to deliver more targeted treatments.