Imperfect Cognitions

Today's post is by Quinn Hiroshi Gibson and Adam Bradley , on how to understand monothematic delusions. Quinn Hiroshi Gibson Subjects with Capgras delusion form the delusion that a loved one has been replaced by an imposter: The day after her arrival at home, [her] father could not open the front door because YY had locked it from the inside. He rang the bell and YY called the police because ‘there was an impostor outside the house who was picking the lock and pretending to be her father’. (Brighetti at al. 2007, p. 191)   Capgras is a monothematic delusion, a delusion whose content is restricted to a single topic, in this case the identity of YY's father. In ‘ Monothematic Delusions and the Limits of Rationality ’ (published in the British Journal for the Philosophy of Science in 2021), we put forward a new account of such delusions. Our view is a version of the two-factor model according to which two factors are responsible for monothematic delusions ( Davies et al. 2001 )...

Today's post is by Eugenia Lancellotta, who has recently completed her doctoral project at the University of Birmingham, on the adaptiveness of delusions and delusions in OCD. Here Eugenia presents some ideas from an article she published in Review of Philosophy and Psychology in 2021, entitled: "Is the biological adaptiveness of delusions doomed? ". Eugenia also discussed some themes from her research in this video interview . Eugenia Lancellotta How likely is it that you father has been replaced by an imposter? Or that you are the Emperor of Antarctica? These beliefs are instances of delusions: fixed, irrational beliefs that are not amenable to change in the face of compelling evidence to the contrary. In popular culture, delusions are considered to be the mark of madness, while psychiatry usually takes them to be the symptoms of a serious mental illness. However, in countertendency to the narrative that sees delusions as pathological, some researchers working in the f...

In this post  Kengo Miyazono  (Hiroshima) and  Ryan McKay  (Royal Holloway) summarise their new paper “ Explaining delusional beliefs: a hybrid model ”, in which they present and defend a hybrid theory of the development of delusions that incorporates the central ideas of two influential (yet sometimes bitterly opposing) theoretical approaches to delusions—the two-factor theory and the prediction error theory.  There are at least two influential candidates for a global theory of delusions (i.e., a theory that explains many kinds of delusions, rather than particular kinds of delusions such as persecutory delusions) in the recent literature: the two-factor theory (Coltheart, 2007 ; Coltheart, Menzies, & Sutton, 2010 ; Coltheart, Langdon, & McKay, 2011 ), according to which delusions are explained by two distinct neurocognitive factors with different explanatory roles, and the prediction error theory (Corlett et al., 2010 ; Corlett, Honey, & Fle...

This post is by Phil Gerrans and Jeanette Kennett . It is a reply to the post we published on Tuesday on Metaethics and Mental Time Travel . In Metaethics and Mental Time Travel , Fileva and Tresan (F&T) fairly and accurately reconstructed (improved?) and intricately dissected our paper. We cannot follow every twist and turn in a short blog post so concentrate on the key issue. They partially agree with us that semantic knowledge detached from diachronic self-awareness is insufficient for moral agency but disagree (i) whether that awareness needs to be "richly experiential" and (ii) the nature of diachronic deficits in the cases we discuss (see their discussion of these cases which is deeper than ours). As they say, Representations with past- or future-oriented, autobiographical content, crucially, awareness of one’s past actions or future options as consistent or inconsistent with one’s principles do seem necessary : but MTT involves experiential repres...

This post is by Federico Bongiorno , a PhD candidate in Philosophy at the University of Birmingham working primarily in the philosophy of mind and cognitive science. Earlier this year, he was a visiting research fellow at Yale University. Here he offers an overview of his paper ‘Is the Capgras delusion an endorsement of experience?' which was recently published in Mind & Language . The Capgras delusion is a condition in which a person believes that a loved one has been replaced by an identical or near-identical other (this can take a variety of forms, such as an imposter, clone, alien, robot, etc.). A more careful definition would specify two propositions that the person believes (Aimola-Davies & Davies, 2009 ): the proposition that someone is not a certain known individual (e.g., this man is not my father ), and the proposition that someone has replaced a certain known individual (e.g., this is a replacer of my father ). I name the content of the former proposi...

In this post, José Eduardo Porcher , Research Fellow at the Rutgers Center for the Philosophy of Religion working primarily in the philosophy of psychiatry and philosophical psychology, outlines his target paper “ Double Bookkeeping and Doxasticism about Delusion ” in the newest issue of Philosophy, Psychiatry & Psychology. Doxasticism about delusion is the theoretical stance according to which delusion is a kind of belief. Although doxasticism is taken for granted in the psychiatric literature, it has been a major point of contention in the philosophical literature, where it has faced many objections and alternative accounts (see e.g. Bortolotti, 2018 ). In my paper, I show how double bookkeeping , a distinctive characteristic of delusional patients, motivates two kinds of argument against doxasticism. I then examine these arguments and find them inconclusive. So what is double bookkeeping? Consider the following excerpt of an interview with a patient who showed symptoms ...

In this post, Phil Corlett replies to Ryan McKay 's summary of his paper " Measles, Magic and Misidentifications: A Defence of the Two-Factor Theory of Delusions ", itself a response to Phil's earlier post on his paper " Factor one, familiarity and frontal cortex: a challenge to the two-factor theory of delusions ". See also Amanda Barnier 's important commentary on the debate, and Phil's reply . Got all that? Right, on with the post! I am grateful to Ryan for his careful and collegial rebuttal of my critique. I am grateful too for the opportunity to respond. Ryan’s response does mollify some of my points. However, I am sure no one will be surprised that I have not updated my beliefs about 2-factor theory. First, Ryan suggests that 2-factor theorists knew about the breadth of the deficits of vmPFC cases, since they were described in Langdon and Coltheart’s ( 2000 ) paper. They were indeed described. Why then, 19 years (and hundreds...

I'm Ryan McKay , Professor of Psychology at Royal Holloway, University of London , and head of the Royal Holloway Morality and Beliefs Lab (MaB-Lab) . I'm interested in how we form and revise beliefs, including delusional beliefs. This post is a summary of my article “Measles, Magic and Misidentifications: A Defence of the Two-Factor Theory of Delusions” in reply to Phil Cortlett's recent paper discussed on the blog last week . The Two-Factor Theory of Delusions One may (a) interpret data falsely, but also (b) receive false data for interpretation. ~ Southard, 1912 , p. 328. The idea that delusions arise when individuals attempt to interpret “false data” has been incorporated in several theories of delusions. Two-factor theorists, however (e.g., Coltheart et al., 2011; Davies & Coltheart, 2000 ; Langdon & Coltheart, 2000 ), view deluded individuals both as “receiving false data for interpretation” (factor one, which furnishes the content of the del...

In this post,  Phil Corlett , Associate Professor of Psychiatry at Yale School of Medicine, discusses some of the ideas in his  paper  ‘Factor one, familiarity and frontal cortex: a challenge to the two-factor theory of delusions’ recently published in the Journal of Cognitive Neuropsychiatry. Over recent years, Imperfect Cognitions has become the premier hub and outlet for work on the neurobiology and cognitive psychology of delusions. It has featured my work on aberrant prediction error and delusions in schizophrenia (Corlett et al., 2007 ), and work that conceptually replicates it (Kaplan et al., 2016 ). There has been work, also highlighted on the blog, from neurological patients that suggest instead that a 2-factor explanation of delusions may be more appropriate (Darby et al., 2017 ), although that work was not conclusive (McKay and Furl, 2017 ). It has all garnered much interest. Partly because delusions inherently fascinating, I think, and partly becaus...

On 6th and 7th November, Ema Sullivan Bissett organised a conference on  Belief, Imagination, and Delusion  at the University of Birmingham. The PERFECT team attended the event and this report is the result of their collective effort! Anna Ichino on imagination Paul Noordhof on aim of belief Sophie Archer (Cardiff University) started the conference with a discussion of delusion and belief, inviting us to learn some lessons from the implicit bias literature. When the avowed anti-racist says all races are equal but does not behave in ways consistent to this belief, then we assume that there is an additional mental state (not open to consciousness) that is responsible for those behaviours. Is this additional mental state a belief? Archer argues that it is not. On the background, there is a thesis about belief. Even if a mental state responds directly to epistemic reasons, this is necessary but not sufficient for the mental state to be a belief (Epistemic Reasons). ...

Wesley Buckwalter is an incoming Presidential Fellow and permanent faculty member at the University of Manchester. In this post, he discusses his paper “ Mind-Brain Dichotomy, Mental Disorder, and Theory of Mind ” recently published in Erkenntnis. Stigmatization of mental illness is widespread . Misunderstanding, bias, and discrimination associated with mental health concerns pervade even our closest interpersonal relationships, continue despite educational background or medical training, and create major obstacles to treatment and recovery within our health care system. It is essential to understand this stigma and its origins to prevent these negative outcomes. As surprising at it may at first sound, some misconceptions about mental health are thought to stem from a centuries-old philosophical theory about the mind. According to this theory, often labeled the “dualist approach” to psychiatry, the mind is essentially distinct in kind from other physical systems. If it is ...

In this post, I report on our third annual workshop, this year with a focus on confabulation, which took place last month at St Anne’s College, Oxford. We had an international programme of talks from both philosophers and psychologists, and talks addressed a range of topics, including exploration of both the varieties and boundaries of the phenomenon of confabulation; application of the notion to new areas of study; and how developments in conceptual models of confabulation influence new therapeutic interventions. Sarah Robins addressed the phenomenon of mnemonic confabulation, or confabulation in memory. In her talk, she demonstrated that although discussions of confabulation began with aspects of memory, mnemonic confabulation is importantly dissimilar from other confabulatory phenomena. In mnemonic confabulation, there is no relationship between the remembered event and an occurrence in the rememberer’s past. However, claiming to remember an event is generally considered ...

Today's post is by Dan Williams, a PhD candidate in the Faculty of Philosophy, at the University of Cambridge. If you had to bet on it, what’s the probability that your loved ones have been replaced by visually indistinguishable imposters? That your body is overrun with tiny parasites? That you’re dead? As strange as these possibilities are, each of them captures the content of well-known delusional beliefs: Capgras delusion, delusional parasitosis, and Cotard delusion respectively. Delusional beliefs come in a wide variety of forms and arise from a comparably diverse range of underlying causes. One of the deepest challenges in the contemporary mind sciences is to explain them. Why do people form such delusions? And why on earth do they retain them in the face of seemingly overwhelming evidence against them? My new paper “ Hierarchical Bayesian Models of Delusion ” presents a review and critique of a fascinating body of research in computational psychiatry that at...

Quinn Hiroshi Gibson is currently a Teaching Fellow in the Global Perspectives on Society program at New York University Shanghai. He received his PhD in philosophy from the University of California, Berkeley in 2017. He works on the moral psychology of self-deception, addiction, delusion, and other psychiatric disorders. His personal website can be found here . In my recent article ‘ Self-deception in and out of Illness: Are some subjects responsible for their delusions ?’ I argue that there is significant overlap between self-deception and delusion. Obviously, whether this is true depends on how we think about self-deception. So, in this paper I offer an account of self-deception, which I call Self-deception as Omission. According to my view, self-deception that p occurs if an agent `intentionally omits to seek, recognize, or appreciate externally available evidence for not- p , for reasons which ultimately derive from her desire that that p be true...

On Wednesday 23rd May, PERFECT will host its third annual workshop, at St Anne’s College, Oxford . This year, our topic is confabulation, and we’re excited to welcome leading researchers in the field for a stimulating programme of presentations. The talks explore a number of philosophical issues arising from confabulation, and will be of interest to philosophers of mind, philosophers of psychology and epistemologists. Papers to be presented also examine confabulation in relation to wider research programmes in cognitive science and psychiatry, and so we also welcome researchers from all disciplines of the mind who are interested in how we give accounts of our experiences, choices and actions. The speakers will address a range of issues, with some exploring an aspect of confabulation that is underdeveloped or has been overlooked in previous work, whilst others propose a new model of the phenomenon that helps to explain and bring clarity to existing observations. I...

In this post, Chris Weigel discusses her paper “Quotidian Confabulations: An Ethical Quandary Concerning Flashbulb Memories,” published in Theoretical and Applied Ethics in 2014. Chris is a professor of philosophy at Utah Valley University. She works mainly on experimental philosophy of free will and on cognitive biases. How did you find out about the planes crashing on September 11, 2001? What do you remember about the first time you met your spouse? Wait, don’t answer those questions! Your memories about those events are flashbulb memories—memories of surprising, monumental, and emotionally-laden events—and my paper invites us to rethink asking people for their memories about these events, such as the Challenger explosion, assassinations of important public figures, and terrorist attacks. My conclusion isn’t that we should never ask people about their flashbulb memories, but rather that sometimes asking people about their flashbulb memories is problematic. It’s problematic ...

This post is by Matthew Parrott and Philipp Koralus. In a previous post they summarised their recent paper ‘ The Erotetic Theory of Delusional Thinking ’, published in Cognitive Neuropsychiatry. Ryan McKay, in a post the following week, summarised his recent paper responding to Matthew and Philipp, ' Bayesian Accounts and Black Swans: Questioning the Erotetic Theory of Delusional Thinking '. In this post, Matthew and Philipp respond to Ryan. We are very grateful to Ryan McKay for taking the time to read our paper, and for formulating helpful questions in response to it. We hope that by addressing these questions, we can clarify any aspects of our theory that might be puzzling. 1) How can we reliably distinguish exogenous and endogenous question raising? As we said in our original post, we propose that patients ‘entertain roughly the same default questions that most people strongly associate with various external stimuli, but that they either envisage fewer alternative ...