The doxastic shear pin: delusions as errors of learning and memory

ABSTRACT

We reconsider delusions in terms of a “doxastic shear pin”, a mechanism that errs so as to prevent the destruction of the machine (brain) and permit continued function (in an attenuated capacity). Delusions may disable flexible (but energetically expensive) inference. With each recall, delusions may be reinforced further and rendered resistant to contradiction. We aim to respond to deficit accounts of delusions – that delusions are only a problem without any benefit – by considering delusion formation and maintenance in terms of predictive coding. We posit that brains conform to a simple computational principle: to minimize prediction error (the mismatch between prior top-down expectation and current bottom-up input) across hierarchies of brain regions and psychological representation. Recent data suggest that delusions may form in the absence of constraining top-down expectations. Then, once formed, they become new priors that motivate other beliefs, perceptions, and actions by providing strong (sometimes overriding) top-down expectation. We argue that delusions form when the shear-pin breaks, permitting continued engagement with an overwhelming world, and ongoing function in the face of paralyzing difficulty. This crucial role should not be ignored when we treat delusions: we need to consider how a person will function in the world without them..

KEYWORDS:

• Belief
• delusion
• epistemic benefit
• prediction error
• schizophrenia

Acknowledgements

We are very grateful to Adina Bianchi and Jacob Leavitt who read and commented on drafts of this paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

S. K. Fineberg http://orcid.org/0000-0001-6024-6721

P. R. Corlett http://orcid.org/0000-0002-5368-1992

Additional information

Funding

This work was supported by the Connecticut State Department of Mental Health and Addiction Services. P.R.C. was funded by an IMHRO/Janssen Rising Star Translational Research Award and CTSA [grant number UL1 TR000142] from the National Center for Research Resources (NCRR) and the National Center for Advancing Translational Science (NCATS), components of the National Institutes of Health (NIH), and NIH roadmap for Medical Research. S.K.F. was supported by NIMH [grant number 5T32MH019961], “Clinical Neuroscience Research Training in Psychiatry”. The contents of this paper are solely the responsibility of the authors and do not necessarily represent the views of the NIH.