Skip to main content

PERFECT Launch (2): Biological Function and Formation of Delusions

Our project logo.
My research so far has been on belief, and this is an area I will continue to focus on. I am interested in researching two main areas: first, how best to think about delusional beliefs when we look to the biological function of belief, and second, accounts of delusion formation.

In my PhD I defended a biological account of belief according to which our mechanisms of belief-production have (at least) two biological functions proper to them. The first is the function to produce true beliefs, and the second is the function to produce useful beliefs. When I say ‘useful’, I do not mean useful an approximation to truth, but rather useful with respect to facilitating the effective functioning of the believer. I was mainly concerned with explaining the connection between belief and truth, and so much of the work was done by appeal to the function of producing true beliefs. However, towards the end of my thesis, I gestured towards the kind of explanatory work which might be done by appeal to the function of producing useful belief.

In terms of future research I am very keen to think about how much work the functional account of belief I developed in my doctoral work can do when we look to pathological belief in the clinical population, specifically, delusional belief. I think there are several questions to ask about delusional belief in the context of my account. Firstly, what is the biological proper function of delusional belief?

We might think of delusional beliefs as being produced by mechanisms functioning to produce useful beliefs, those same mechanisms which function to produce beliefs in line with partiality and self-enhancement biases, and self-deception. If delusional beliefs have biological functions proper to them in virtue of their being adaptive insofar as they are pragmatically beneficial, there is then a question about what the Normal (normative historical, not statistical) conditions are for the performance of that function. So what has to be the case such that our mechanisms for belief production are functioning Normally or properly when they produce a delusional belief?

We might instead conceive of delusional beliefs as cases of malfunction, so cases of failure. So whereas they ought to have been true beliefs, they fail in this respect, and we have a case of malfunction. Or perhaps they are produced by the same mechanisms which function to produce useful beliefs, but they malfunction insofar as they produce beliefs which do not help facilitate the effective functioning of an agent. It is not yet clear then how we ought to understand delusional beliefs in the context of the biological histories of our mechanisms for belief-production. Either they are produced by mechanisms with proper functions, functioning properly under Normal conditions, or they are malfunctioning items.

With respect to the topic of delusion formation, I am interested in developing and defending a one-factor account. One-factor accounts have it that a subject forms a delusional belief on the basis of an anomalous experience, such that there is no abnormal deficit in her mechanisms of belief formation, the psychology thereof is within the normal range of human psychology. I think that there is word to be done in developing the one-factor approach. For one thing, the notion of 'normal range' needs to be carefully worked out. 'Normal range' cannot just include rational responses to one's evidence or experience, for then we are in danger of ruling out too much (now self-deceivers, conspiracy theorists, and even suitably stubborn scientists will fall outside of the 'normal range'). Rather, our notion of 'normal range' needs to be one which rules out abnormal cognitive deficits (postulated by multi-factor accounts) but rules in a range of rational and irrational beliefs. I also think that several objections have been raised to one-factor approaches which have not yet been answered (and I think they can be).

I have interviewed Max Coltheart on this topic, the first half of this will be published on the blog later this month.

And here I talk about my plans for the first year of project PERFECT (video).

Popular posts from this blog

Delusions in the DSM 5

This post is by Lisa Bortolotti. How has the definition of delusions changed in the DSM 5? Here are some first impressions. In the DSM-IV (Glossary) delusions were defined as follows: Delusion. A false belief based on incorrect inference about external reality that is firmly sustained despite what almost everyone else believes and despite what constitutes incontrovertible and obvious proof or evidence to the contrary. The belief is not one ordinarily accepted by other members of the person's culture or subculture (e.g., it is not an article of religious faith). When a false belief involves a value judgment, it is regarded as a delusion only when the judgment is so extreme as to defy credibility.

Rationalization: Why your intelligence, vigilance and expertise probably don't protect you

Today's post is by Jonathan Ellis , Associate Professor of Philosophy and Director of the Center for Public Philosophy at the University of California, Santa Cruz, and Eric Schwitzgebel , Professor of Philosophy at the University of California, Riverside. This is the first in a two-part contribution on their paper "Rationalization in Moral and Philosophical thought" in Moral Inferences , eds. J. F. Bonnefon and B. Trémolière (Psychology Press, 2017). We’ve all been there. You’re arguing with someone – about politics, or a policy at work, or about whose turn it is to do the dishes – and they keep finding all kinds of self-serving justifications for their view. When one of their arguments is defeated, rather than rethinking their position they just leap to another argument, then maybe another. They’re rationalizing –coming up with convenient defenses for what they want to believe, rather than responding even-handedly to the points you're making. Yo...

A co-citation analysis of cross-disciplinarity in the empirically-informed philosophy of mind

Today's post is by  Karen Yan (National Yang Ming Chiao Tung University) on her recent paper (co-authored with Chuan-Ya Liao), " A co-citation analysis of cross-disciplinarity in the empirically-informed philosophy of mind " ( Synthese 2023). Karen Yan What drives us to write this paper is our curiosity about what it means when philosophers of mind claim their works are informed by empirical evidence and how to assess this quality of empirically-informedness. Building on Knobe’s (2015) quantitative metaphilosophical analyses of empirically-informed philosophy of mind (EIPM), we investigated further how empirically-informed philosophers rely on empirical research and what metaphilosophical lessons to draw from our empirical results.  We utilize scientometric tools and categorization analysis to provide an empirically reliable description of EIPM. Our methodological novelty lies in integrating the co-citation analysis tool with the conceptual resources from the philosoph...