Bayesian accounts of perceptual decisions in the nonclinical continuum of psychosis: Greater imprecision in both top-down and bottom-up processes

Isabella Goodwin (University of Melbourne)

Please note that this talk is at 11am-12pm Australian Eastern Standard Time.

Description: Investigating psychotic-like experiences in non-clinical populations can aid our understanding of how and why altered perceptual experiences arise in psychosis. Conflicting Bayesian theories postulate aberrations in either top-down or bottom-up processing. On one hand, psychotic-like experiences might arise due to an overreliance on current sensory information in one’s environment with a reduced regard for prior context during perceptual decision making. Alternatively, this might be due to an overreliance on contextual information such as prior beliefs and expectations. In this talk, I will outline our research where we empirically adjudicate between these hypotheses, using a perceptual decision-making task in which the uncertainty of prior beliefs and sensory information is manipulated. We found that people with greater psychotic-like experiences relied more on sensory information relative to prior expectations across the task. This was driven by the perception of greater uncertainty or unreliability associated with prior information. Psychotic-like experiences were also associated with a general perception of greater task instability, which unifies these conflicting hypotheses. Our findings show that alterations in belief updating extend into the non-clinical continuum of psychotic-like experiences, which provides important utility in understanding the continuum of psychosis.

Zoom link: https://monash.zoom.us/j/84663747139?pwd=OWZiajBnZHRVMS9SR2I3NVk5QkpkZz09