Delusions and delusional reasoning.

In 2 studies, delusional participants assigned higher probabilities to narratives of actual delusions than participants with no history of delusions; previously delusional participants did not differ significantly from delusional participants or participants with no history of delusions. In Study 2, the authors found that this reasoning bias was specific to delusions and did not generalize to "neutral" text. Familiarity with the content of the delusion narratives played a mediating role in the estimation of their probability, but delusional status also had a significant, independent effect. These findings are consistent with the Bayesian model of delusion formation proposed by D. R. Hemsley and P. A. Garety (1986), and with R. P. Bentall, P. Kinderman, and S. Kaney's (1994) concept of "emotional saliency." A productive area of future research might be to further determine the elements of "emotional saliency" and their impact on the individual steps of the Bayesian model.