Imperfect Cognitions

In today's post I report on the Summer School in Reichenau   which I had the pleasure to attend on 25th and 26th August 2023. The theme was Belief, meaning, knowledge: how we deal with uncertainty . Delusions was a topic often discussed in the presentations, from philosophical, phenomenological, and clinical perspectives. Organisers of the event were Johannes Rusch, Daniel Nischk, Dorothea Debus, and Thomas Müller. Rathaus Reichenau (front) Rathaus Reichenau (courtyard) The first speaker was Rico Gutschmidt (Konstanz) with a presentation on Mysticism and Delusions . Fundamental uncertainties are limitations of knowledge and experience and three questions arise: (1) Where do we come from? (2) Why there is anything at all rather than nothing? (3) Who are we? Although such questions are not easy to answer or possible to answer they can evoke transformative experiences. Philosophical experiences such as struggling with these questions can be transformative because they change the type...

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...

Today's post is by Kengo Miyazono , Hiroshima University, who talks about his latest book, Delusions and Beliefs (Routledge 2018). This book addresses the following theoretical questions about delusions: (1) The Nature Question : What is a delusion? In particular, what kind of mental state is it? The standard view in psychiatry is that delusions are beliefs. But, is this view (‘doxasticism about delusion’) really true? Delusions have a number of peculiar features that are not belief-like, such as the remarkable insensitivity to evidence. Are these peculiar features consistent with the doxastic conception of delusions? (2) The Pathology Question : Delusions are pathological mental states. Delusions, together with other symptoms, warrant clinical diagnoses and treatments. Why are delusions pathological? What distinguishes pathological delusions from non-pathological irrational beliefs? Are delusions pathological because they are too irrational? Or, are they pathological because...

On 15th October at Hornton Grange Matthew Broome , director of the Institute for Mental Health  in Birmingham, chaired the book launch of Delusions in Context (Palgrave Pivot, 2018), a collection of four new papers on delusions. The book is truly interdisciplinary, featuring authors with a background in psychiatry, lived experience, psychology, cognitive neuroscience, and philosophy, and is available open access on the Springer website . I edited the book. At the launch, I explained how the book fits with the work we have been doing as part of project PERFECT . In the project one of the objectives is to examine whether beliefs that we consider as epistemically irrational (either not supported by existing evidence, or resistant to new counter-evidence) can nonetheless have some benefits for the person who adopts such beliefs. Benefits could be cashed out in terms of increased wellbeing or reduced anxiety, enhanced motivation to pursue epistemic goals, or better performance i...

The Royal College of Psychiatrists hosted its  Faculty of Neuropsychiatry Annual Conference on 13-14 September 2018 in London. I was fortunate to attend the first day and I am going to report on some of the interesting talks I listened to. In the first session speakers focused on neuroscience for psychiatrists, and Paul Johns, author of Clinical Neuroscience , addressed the functional anatomy of the human amygdala. The amygdala is constantly looking out for dangers and helps us evaluate the emotional significance of events. It facilitates social interactions as it enables us to read other people's minds. Further, the amygdala is involved in learning and episodic memory for important events. It is responsible for an implicit emotional memory of negative events to help us avoid adverse stimuli. The amygdala is for assessing environmental cues to determine the adequate response to threats. So patients without the amygdala are fearless but it is possible to experimentall...

This post is a reply by Phil Corlett (Yale)  (pictured below) to Dan Williams's recent post on Hierarchical Bayesian Models of Delusions . Dan Williams has put forward a lucid and compelling critique of hierarchical Bayesian models of cognition and perception and, in particular, their application to delusions. I want to take the opportunity to respond to Dan’s two criticisms outlined so concisely on the blog (and in his excellent paper) and then comment on the paper more broadly. Dan is “ sceptical that beliefs—delusional or otherwise—exist at the higher levels of a unified inferential hierarchy in the neocortex . ” He says, “ every way of characterising this proposed hierarchy... is inadequate .” Stating that “ it can’t be true both that beliefs exist at the higher levels of the inferential hierarchy and that higher levels of the hierarchy represent phenomena at large spatiotemporal scales . There are no such content restrictions on beliefs, whether delusional ...

My name is Andrew Sims . Right now I’m working as a post-doctoral researcher at the Université Catholique de Louvain, in an Action de Recherche Concertée (ARC) project on action theory and neuroscience. Before this, though, I wrote my PhD dissertation in the philosophy department at Deakin University and while visiting at the Department of Clinical, Health and Educational Psychology at University College London. My dissertation focused upon the psychodynamic explanation of anosognosia for hemiplegia (AHP)—denial of paralysis—and its relationship to cognitive deficit models of the condition. I’ve recently had an article published in the Review of Philosophy and Psychology that draws upon some of this work (Sims 2017). Thanks very much to Andrea Polonioli for inviting me to introduce it on the Imperfect Cognitions blog. AHP occurs after brain damage and involves a paralysis on one side along with various attitudinal distortions toward that paralysis. At a minimum, this is an inabil...

In this post, Andy Clark , Professor of Logic and Metaphysics at the University of Edinburgh, introduces his new book: Surfing Uncertainty: Prediction, Action, and the Embodied Mind . Sometimes, we are most forcibly struck by what isn’t there. If I play you a series of regularly spaced tones, then omit a tone, your perceptual world takes on a deeply puzzling shape. It is a world marked by an absence – and not just any old absence. What you experience is a very specific absence: the absence of that very tone, at that very moment. What kind of neural and (more generally) mental machinery makes this possible? There is an answer that has emerged many times during the history of the sciences of the mind. That answer, appearing recently in what is arguably its most comprehensive and persuasive form to date, depicts brains as prediction machines – complex multi-level systems forever trying pre-emptively to guess at the flow of information washing across their many sensory sur...

In this post, Sophie Stammers reports from the Chandaria Lectures , hosted by the School of Advanced Study at the University of London. Professor Andy Clark , of the University of Edinburgh, gave the annual lecture, where he introduced the notion of ‘predictive processing’. Over the course of the three lectures, he put forward the case for understanding many of the core information processing strategies that underlie perception, thought and action as integrated through the predictive processing framework. On a model of perception popular with Cartesians, and undoubtedly dominant in areas of the cannon that I was acquainted with as an undergraduate, perception is something of a passive business. Perceivers employ malleable receptor systems that (aim to) faithfully imprint the world as it is, delivering a raw stream of information that is made sense of downstream in later processing. Clark dubs this the “cognitive couch potato view”. Despite its past popularity, this view see...

Pacifico, Yokohama PERFECT was invited to present a symposium at the 31st International Congress of Psychology (ICP), which took place at Pacifico Yokohama in Japan and was attended by over 8000 people from 95 countries. The symposium, entitled ‘Explaining Delusion: Empirical and Theoretical Approaches to Delusion Formation’ featured speakers from philosophy (myself,  Rachel Gunn ), Kengo Miyazono and Phillip Gerrans) and from psychology (Eriko Sugimori and Rochelle Cox). Eriko Sugimori ’s talk entitled ‘Effects of Positive and Negative Delusional Ideation on Memory’ covered a study where participants were given a learning task in which they were shown 40 adjectives projected one at a time on a screen.  Fifteen minutes later they were shown 80 adjectives and asked to state whether those adjectives had featured in the learning task. The participants were assessed for delusion proneness as well as degree of positive delusional ideation (consisting of traits such as guarde...

This is the second in a series of two posts by Phil Corlett (pictured above) and Sarah Fineberg (pictured below). Phil and Sarah are both based in the Department of Psychiatry at Yale University. In a post published last week, and this post they discuss the adaptive value of delusional beliefs via their predictive coding model of the mind, and the potential delusions have for epistemic innocence  (see their recent paper ' The Doxastic Shear Pin: Delusions as Errors of Learning and Memory ', in Cognitive Neuropsychiatry) .  Phil presented a version of the arguments below at the Royal College of Psychiatrists' Annual Meeting in Birmingham in 2015, as part of a session on delusions sponsored by project PERFECT.  Our analysis depends on two distinct systems for instrumental learning, one goal-directed, the other habitual (Daw et al., 2005 ). The goal-directed system involves learning flexible relationships between actions and outcomes instantiated in the more...

This is the first in a series of two posts by Phil Corlett (pictured above) and Sarah Fineberg (pictured below). Phil and Sarah are both based in the Department of Psychiatry at Yale University. In this post and the next they discuss the adaptive value of delusional beliefs via their predictive coding model of the mind, and the potential delusions have for epistemic benefits (see their recent paper ' The Doxastic Shear Pin: Delusions as Errors of Learning and Memory ', in Cognitive Neuropsychiatry). Phil presented a version of the arguments below at the Royal College of Psychiatrists' Annual Meeting in Birmingham in 2015, as part of a session on delusions sponsored by project PERFECT . The predictive coding model of mind and brain function and dysfunction seems to be committed to veracity; at its heart is an error correcting, plastic, learning mechanism that ought to maximize future rewards, and minimize future punishments like the agents of traditional microec...

This is our third of a series of posts in the papers published in an issue of Avant on Delusions. Here  Rick Adams  summarises his paper (co-written with Harriet R. Brown and Karl J. Friston ) ' Bayesian Inference, Predictive Coding and Delusions '. I am in training to become a psychiatrist. I have also recently completed a PhD at UCL under Prof Karl Friston , a renowned computational neuroscientist. I am part of a new field known as Computational Psychiatry (CP). CP tries to explain how various phenomena in psychiatry could be understood in terms of brain computations (see also Corlett and Fletcher 2014 , Montague et al.,  2012 , and Adams et al. forthcoming in JNNP ). One phenomenon that ought to be amenable to a computational understanding is the formation of both ‘normal’ beliefs (i.e. beliefs which are generally agreed to be reasonable) and delusions. There are strong theoretical reasons to suppose that we (and other organisms) form beliefs in a Bayesi...

Max Coltheart This is the first in a series of posts on the papers published in an issue of AVANT on Delusions. Here  Max Coltheart  summarises his paper  ' From the Internal Lexicon to Delusional Belief '. Ten years ago, in an article on the two-factor theory of delusion, I wrote:  'Suppose that as we go about everyday life we use an internal model of the world (Gray  1995 ;  Sokolov  1963 ) to continuously predict what we will experience next. These predictions will normally be fulfilled, but occasionally not: occasionally something not predicted by the internal model occurs. That event indicates that there is something wrong with the database of beliefs that the model uses to predict what will happen next in the world. So the database needs to be fixed (by modifying e xisting beliefs or adopting new ones) so that it becomes compatible with the unexpected event' (Coltheart 2005 ). As I emphasize in my Avant  article, this is th...

This a response to Phil Corlett's  contribution to the blog , posted on behalf of Max Coltheart. Max Coltheart Dear Phil Let’s focus for the moment on the best-studied monothematic delusion, Capgras delusion, and let me ask you two questions so that we can decide whether your account differs from ours. First question: there are 3 studies of autonomic responding to familiar faces in patients with Capgras delusion, and all showed that these deluded patients don’t show greater response when faces are familiar than when they are not, and general show weak faces. Would you agree that this abnormality is not a coincidence, but instead plays a causal role in the delusion? And if your answer is Yes, what do you see this causal role as being? (Our answer to this question: the absence of autonomic response to the face of a spouse is unexpected i.e. unpredicted, and that triggers a search for an explanation of the prediction error, which takes the form of a candidate belief)...

This is a response to Max Coltheart's contribution to the blog , posted on behalf of Phil Corlett.   Phil Corlett Thanks Max. I suppose if a two-factor explanation of polythematic delusions is an open question, then an aberrant prediction error explanation of monothematic delusions is likewise open. I think our theories have more in common than perhaps we are allowing with this debate and our apparent disagreement. I think we are talking about different levels of explanation (Marr, 1977). My implementational and algorithmic explanations may be overlapping with your computational one, but it seems you disagree. This is curious and unfortunate, since prediction error is at the heart of both of our explanations. We make our prediction error case using behavioral and functional imaging data – if people with monothematic delusions were to show aberrant prediction error signals that correlate with delusion severity (as we showed in endogenous and pharmacological settings as...

This is a response to Phil Corlett's  contribution to the blog , posted on behalf of Max Coltheart.  Max Coltheart I think it would be helpful if at this stage the distinction between monothematic and polythematic delusions were introduced. A monothematic delusional condition is one where the patient has only a single delusional belief (or a small set of delusional beliefs related to a single theme). A polythematic delusional condition is one where the patient has many different and unrelated delusional beliefs. This distinction between monothematic and polythematic delusion was offered by Davies, Coltheart, Langdon and Breen (2001) and has been discussed by the philosopher Jennifer Radden in her book (Radden, 2010). As Coltheart (2013) noted “Well-known cases of polythematic delusion include Daniel Schreber, a judge in the German Supreme Court, who believed that he had the plague, that his brain was softening, that divine forces were preparing him for a sexual union wi...

Phil Corlett This is a response to Max Coltheart's  contribution to the blog , posted on behalf of Phil Corlett. Thank you Max. Your responses are enlightening. I do have a number of follow-up questions, if I may. Follow up to Q 1 – If prediction error is intact in people with delusions, how would we observe the patterns of prediction error disruption in our data? These patterns have been consistent across endogenous ( Corlett et al., 2007 ) and drug induced delusions ( Corlett et al., 2006 ) as well as in healthy people with delusion-like ideas (beliefs in telekinesis for example) ( Corlett & Fletcher, 2012 ). Importantly, these neural responses (aberrant prediction errors) correlated with delusion severity across subjects in these studies. On the other hand, if prediction error must be intact for 2-factor theory, do our data suggest that 2-factor theory not apply to delusions that occur in schizophreniform illnesses?

This is a response to Phil Corlett's  contribution to the blog ,  posted on behalf of Max Coltheart. Max Coltheart I thank Phil for his illuminating questions about my post, and will attempt to answer them, in Q&A format (Q is Phil, A is me). Q: Are you aligning prediction error with Factor 1 or Factor 2? It seems Factor 1, but I wanted to check – particularly since you align Factor 2 with the functioning of right dorsolateral prefrontal cortex, which, as you know, we’ve implicated in prediction error signaling with our functional imaging studies. A: In our account, what generates prediction error is Factor 1: for example, in Capgras delusion, the prediction is that an autonomic response will occur when the face of one’s spouse is seem, but that prediction is in error, since the predicted response does not occur. But detection of this prediction error would only occur if the system that detects such errors is intact. And the job of this system is to generate ...

This is a response to Max Coltheart's post (and comments) , posted on behalf of Phil Corlett. Phil Corlett As usual Max, a thorough, interesting and well written piece. I am curious about a couple of things. First, you say that the prediction error signal fails in our model. Are you implying that we believe delusions form in the absence of prediction error? Our data point to the opposite case. Prediction errors are inappropriately engaged in response to events that ought not to be surprising. That is why people with delusions learn about events (stimuli, thoughts, percepts) that those without delusions would ignore. Second, you claim that prediction error is key to belief updating in your model. Are you aligning prediction error with Factor 1 or Factor 2? It seems Factor 1, but I wanted to check – particularly since you align Factor 2 with the functioning of right dorsolateral prefrontal cortex, which, as you know, we’ve implicated in prediction error sign...