The Role of Unconscious Inference in Models of Delusion Formation

In this chapter we discuss the role of conscious and unconscious inference in theories of delusion formation. Two competing accounts aim to shed light on the formation of delusions: according to explanationism, the delusional belief is offered as an explanation for anomalous experience; according to the endorsement theory, the delusional belief is an acknowledgement that the anomalous experience is veridical. Whereas explanationists argue that the delusional belief is inferred from experience, endorsement theorists argue that there need be no inference from the experience to the delusional belief. Here we put pressure on the idea that the two accounts can be distinguished on the basis of whether inference is involved in delusion formation and argue that they are both compatible with the increasingly influential idea that Bayesian inference is responsible for the adoption of the delusional belief. One of the models of delusion formation focusing on Bayesian inference is the Coltheart model (Coltheart, Menzies, and Sutton, 2010) which we discuss in detail in the chapter. We show that, given its features, the model does not fit neatly under either explanationism or the endorsement theory.