Bayesian Reasoning with Emotional Material in Patients with Schizophrenia

Delusions are one of the most classical symptoms described in schizophrenia. However, despite delusions seldom exist in the absence of affective content, they have been investigated using tasks involving non-affective material, such as the Beads task. In this study we compared 30 patients with schizophrenia experiencing delusions with 32 matched controls in their pattern of responses to two versions of the Beads task within a Bayesian framework. The two versions of the Beads task consisted of one emotional and one neutral, both with ratios of beads of 60:40 and 80:20, considered respectively as the ‘difficult’ and ‘easy’ variants of the task. Results indicate that patients showed a greater deviation from the normative model, especially in the 60:40 ratio, suggesting that more inaccurate probability estimations are more likely to occur under uncertainty conditions. Additionally, patients show a greater deviation in the emotional version of the task, providing evidence of a reasoning bias modulated by the content of the stimuli. These results contribute to the understanding of how cognitive mechanisms interact with characteristics of the task (i.e., ambiguity and content) in the context of delusional thinking. These findings might be used to inform improved intervention programs in the domain of inferential reasoning.