Thursday, 20 June 2019

Epistemic Duty Workshop

We often say things like “you shouldn’t believe that the Earth is flat” or “just look at the evidence, you really ought to believe that vaccinations save lives”. Just as one might think that we have particular obligations to behavemorally, one might suspect that this sort of talk reveals that we have obligations to believeparticular things, or perhaps, to believe in a particular way. Is that right? And if so, what do those obligations consist in?

On 30th – 31st May, a workshop investigating issues related to these questions was held at St. Thomas University, Fredericton, New Brunswick, Canada. Organised by Scott Stapleford, Professor of Philosophy at St Thomas University, and Kevin McCain, Associate Professor in Philosophy at the University of Alabama at Birmingham, the workshop comprised eight talks over the course of two days. Here, I summarize just a few of them.

Sharon Ryan was interested in the question of whether we have an epistemic obligation to be open-minded. She maintained that we do have epistemic responsibilities, and moreover, that our epistemic responsibilities are among some of the most important. For Sharon, understanding reality certainly has instrumental value (in so far as it helps us to fulfil our practical goals) but it is also intrinsicallygood. Sharon suggested that one of the significant outputs of philosophy is that it helps to make us more epistemically responsible.

She argued there is a particular conception of open-mindedness that is a necessary condition for wisdom. She first examined some alternative constructions of open-mindedness, and found them deficient. For instance, a construction on which being open-minded amounts to withholding judgements on propositions about reality, or one which centers being aware of one’s own fallibility as a believer, might point to epistemically valuable characteristics, but also don’t give us positive instructions regarding how we should navigate information.

Wednesday, 19 June 2019

The Two-factor Theory of Delusions: A reply to Amanda Barnier

This post is by Philip Corlett who is currently engaging in a debate with Ryan McKay on this blog about the two-factor theory of delusions (see Phil's and Ryan's previous posts). Here Phil replies to Amanda Barnier's comment.

I am grateful to Amanda for her contributions, to the blog exchange and to the literature on delusions. I am of course aware of her hypnosis work – having spent time at Macquarie and even been hypnotized (I am highly hypnotizable, which is perhaps too much to share here).

My article and post were provocative and perhaps too confrontational. Having spent time at the Belief Formation Program Table, I understand how exciting and generative it can be. My word choice was perhaps a little too strong. 'Adherents' may have been better. I see that 'acolytes' may be particularly insulting to practicing scientists.

My article was about the basic foundational data and arguments of two-factor theory. Whilst Amanda is right to criticize my word choices, and to chastise me for not acknowledging Robyn Langdon, do either of those points detract from my case? To presage next week’s response to Ryan, if 2-F theorists knew about the contents of my article; the broader SCR deficits and right DLPFC lesions in the control cases, why weren’t they mentioned in the many papers on 2-F theory? Did they come up around the big table? They did not when I sat at the table when I visited.

I think some of my vitriol comes from having sat at that very table and shared my ideas and data, only to have them rather harshly derided in print, without forewarning or right to prompt reply. I did eventually get to respond. If we are calling the tone police, I think it apt to return to the scene of the original crime. Squabbling aside, my use of the terms acolyte and magical properties, reflect a dissatisfaction in the way exchanges with 2-F theorists often evolve. If the stall is set out such that only one style of explaining the data, and certain data, are on the table, it is very difficult to disagree.

One must challenge the explanation, and the data, as I did in my article and post.

I could and perhaps should have done so in a less ad hominem way. But it wasn’t all ad hominem. Does Amanda disagree that the imprecise SCR response or the right DLPFC lesions of the VMPFC cases are a problem? Did the big table ever test the 2-F predictions about SCR in the other monothematic delusions? And what of modularity – if it doesn’t obtain, what will be the fate of 2-F? I will unpack these ideas further next week, but did not want to leave Amanda’s important post unanswered.

Two-factor Theory of Delusions: A commentary on the debate

This post is by Amanda Barnier, Professor of Cognitive Science and Associate Dean Research in the Faculty of Human Sciences at Macquarie University. She was Deputy Leader of the Belief Formation Program and Chief Investigator of the Australian Research Council (ARC) Centre of Excellence in Cognition and its Disorders from 2011-2018. In her work she has attempted to use hypnotic methods to recreate clinical delusions in the laboratory. Here she contributes to the exchange between Phil Corlett and Ryan McKay on the two-factor theory of delusions.

I read Phil Corlett’s and Ryan McKay’s blog posts with great interest as well as their original article and commentary. As someone who has worked in the field of delusions (albeit on a bit of a hypnotic tangent) for about 15 years (including for 12 years since I arrived at Macquarie University in 2007 to work with Max Coltheart), I wanted to share some insights.

In his original published article in Cognitive Neuropsychiatry, Phil described me and others who have collaborated with Max Coltheart as “acolytes” who ascribe “magical properties” to the two-factor theory. Here’s the relevant paragraph from Phil’s original paper (with a quote bolded by me):

A colleague and collaborator of Coltheart, and co-creator of two-factor theory, Martin Davies’ remarks of cognitive neuropsychology (Davies, 2010), apply to the strange status that two-factor theory has attained (above reproach, immune to criticism, unmolested by direct empirical examination):
... it is a familiar point about science in general that there is no logically valid deductive inference from evidence to explanatory theory. To be explanatory, a theory must go beyond a summary of the evidence and so cannot be entailed by the evidence. Within the narrower domain of psychology, it is well understood that there is no logically valid deductive inference from data, such as reaction time data, to an explanatory theory about cognitive structures and processes. It is very unlikely that cognitive neuropsychologists regard their research program as being different from all the rest of empirical science and take themselves to have access to evidence with magical properties. (Davies, 2010)
I suggest that acolytes of two-factor theory attribute it the magical properties Davies outlines. It appears to me to be a deduction that is unwarranted by the data. While Coltheart would likely respond that argumentation in cognitive neuropsychology is abductive infer- ence (to the best explanation), I would contend that two-factor theory, as he and his colleagues espouse, is an erroneous summary of rather scant evidence, and so not the best available explanation of those data, nor of delusions.
First, I want to highlight that Associate Professor Robyn Langdon always should be mentioned in discussions of two-factor theory as its co-creator. Her careful, insightful, clinically inspired thinking has been instrumental to both the theoretical and empirical work flowing from the two-factor model. Although mentioning her may not have fit the somewhat combative narrative of Phil’s original article, credit where credit is due.

Tuesday, 18 June 2019

Measles, Magic and Misidentifications

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 delusion) and as “interpreting data falsely” (factor two). Factor two is necessary, they claim, because some patients who appear to “receive false data for interpretation” are not delusional. The two-factor theory is thus based on the dissociation between “false data” and “false belief”.

Take Capgras delusion, for instance. For two-factor theorists, the “false data” in the Capgras case is a deficient autonomic response to familiar faces (indexed by skin conductance response [SCR]). The apparent dissociation between these “false data” and “false belief” comes from the fact that patients with damage to ventromedial prefrontal cortex (vmPFC) have also been shown to have deficient SCRs to familiar faces ¬– but these patients are not delusional (Tranel et al., 1995). So, something must explain why Capgras patients – but not the vmPFC patients – adopt the delusion. For two-factor theorists, that “something” is a deficient ability to evaluate candidate explanations of false data – the eponymous factor two.

Thursday, 13 June 2019

The Medical Model in Mental Health

Today's post is by Dr Ahmed Samei Huda, a Consultant Psychiatrist working mostly in Early Intervention in Psychosis for Pennine Care NHS Foundation Trust. He is introducing his book, The Medical Model in Mental Health: An Explanation and Evaluation (OUP, 2019). Huda is on Twitter (@SameiHuda), and blogs here.

I am a clinician not an academic who became increasingly frustrated with the strawman depictions of psychiatry in the fraught conflicts between different professions and ideologies in mental health. So I decided to read more about what the medical model was and the more I read the more he realised there was an absence of a book explaining from first principles what the medical model was and how it was applied in mental health. 

I’m not a world class expert but my over 20 years experience of clinical practice combined with extensive reading including several volumes of the excellent International Perspectives in Philosophy and Psychiatry series and Davidson’s Textbook of Medicine as well as several hundred papers helped qualify me to write this book and luckily OUP agreed.

The book starts with an outline of the medical model as a model of practice – using the best evidence to guide clinical decision-making – and as a model of explanation (currently biopsychosocial not biomedical) and the lack of clear-cut definitions for disease and illness in all of medicine.

Categorical diagnostic constructs are used as an easy way to acquire, learn and recall relevant information for clinical practice. Doctors match the clinical picture of the patient to the best matching clinical picture of a diagnostic construct. These constructs carry attached information such as on prognosis, complications or treatment effectiveness. 

Diagnostic constructs are classified on similarities of clinical picture, changes in structure/ process and/or causes. They are used to represent several different types of conditions such as spectrums with health, spectrums of conditions, injuries or problems thought to benefit from healthcare professionals’ interventions. Doctors work as part of teams and the medical model is not the only way and not always the best way to help people with the problems they come with to services.

The book then discusses some relevant papers to identify criticisms of psychiatric diagnostic constructs and treatments. The best comparison is with general medicine and the rest of the book analyses the relevant evidence which shows there is significant overlap between psychiatry and general medicine – for example both their diagnostic constructs often lack clear boundaries with healthy states, lack clear boundaries between each other and require additional information apart from diagnosis to guide clinical decision making, lack of knowledge of biological mechanisms or causes and the importance of social factors as well as overlapping effectiveness of their treatments which in both psychiatry and medicine which in both specialties are usually not cures or reverse diseases. 

Psychiatry is thus a member of family of the medical specialties despite the claims of its’ critics but necessarily must work in a multidisciplinary way and diagnostic constructs whilst the most useful classification for social purpose such as access to welfare and administration are often not ideal for different ways of working with mental health patients such as psychotherapy.