Delusions come in many forms, but delusions as psychopathologies of belief possess bizarre conceptual contents, and it is delusions of the bizarre sort, oftentimes critically contributing to illnesses such as schizophrenia, to which this book primarily is devoted.

Materials related to each chapter were first presented at a workshop on the theory of mind and psychopathology in the summer of 1998 at Macquarie University in Australia. They were first published in a special issue of the journal Mind and Language, as volume 15 number 1 (February 2000). Some of the authors are philosophers (Currie, Davies, Gerrans, Gold, and Hohway). Others are psychologists or neuropsychologists (Breen, Caine, Coltheart, Hendy, Langdon, Peterson, Siegal, Roberts and Young).

For many investigators of psychopathology, the place to begin is with case studies. Breen and colleagues (Ch.3) examine four cases of delusions of misidentification, including two of misidentification of a reflected (in a mirror) self, one of reduplicative paramnesia, and one of a women’s belief that she is a man. Breen and colleagues claim that a thorough understanding of bizarre delusions depends upon investigation of differences among both individual patients and delusion types. Readers unfamiliar with the literature on bizarre delusions may do well to begin the book with this chapter, since it helps to reveal the important role which attention to cases can and should play in research on pathologies of belief. The cases also help to orient the reader to the sorts of delusions or pathologies around which the book is organized.

Again with attention to cases, though not delusional, Peterson and Siegal (Ch.5) compare and contrast autistic and deaf children with respect to the nature and development of their understanding of other minds. Peterson and Siegal equate this ability with having and deploying a theory of mind, in the now standard sense of this notion among philosophers and psychologists, meaning, roughly, attributing states of mind, including false beliefs, to other people or agents. The authors explore whether acquiring the ability to attribute mental states to others depends upon features of the social environment in which a child is raised, such as the presence of socially reinforced conversation about thoughts and feelings.

The central focus of the volume, as mentioned above, is bizarre delusions. The rest of the chapters are aimed at uncovering how best to account, psychologically, for various features of bizarre delusions. These features include their onset, variation, and persistence, as well as their impact, or lack thereof, on behavior. There are a variety of psychological factors, which the authors claim are at least in part responsible for one or more features.

Perceptual abnormalities provide one cluster of factors held to be responsible for the onset of some bizarre delusions. Many victims of bizarre delusions seem to base their delusions on aberrant perceptual experiences, which offer subjectively powerful evidence that something bizarre nonetheless is true. Brendan Maher, a psychologist not directly represented in this book, but frequently cited by its contributors, has argued that the subjective impression of various aberrant perceptions is often so powerful, that victims of delusions reason to delusional convictions as best explanations of those perceptions.

The Capras delusion, to treat one example in Maher’s spirit if not letter, consists in believing that imposters have replaced one’s own relatives. Such a delusional inference may be an effort to make sense of the bizarre perceptual fact that the relatives may not seem or feel familiar on face recognition. To some subjects, this perceptual fact may warrant the conviction that one’s relatives are imposters. Young (Ch.2) calls such feelings of familiarity ‘emotionally orienting responses’. The Capgras delusion is mainly found with reference to close relatives, says Young, because these are the people for whom absence of orienting responses is most noticeable and disturbing.

Much of the book concerns whether perception-based hypotheses, such as the appeal to orienting responses above, offer complete explanations of the onset, variation, and persistence of delusions. The consensus of the book’s authors is that they do not. As Young says, ‘there seems to be something missing.’

Misgivings with exclusive appeal to perceptual hypotheses are elaborated in a variety of ways. Some authors, such as Davies and Coltheart in their independently contributory editorial introduction (Ch.1), wonder if reasoning biases or failures of probability reasoning are responsible for some delusions, more or less independent of bizarre perceptual experiences. Gold and Hohwy (Ch.6) are convinced that a failure of reason or rationality occurs in delusions. However they claim that in some delusions (such as that of thought insertion) the relevant irrationality is a feature of bizarre perceptual experience itself. Curie (Ch.7) suspects that a fundamental reasoning error behind delusion formation is that a subject who starts by imagining something to be true (in Capgras that relatives are imposters) somehow comes to believe that it is true. Numerous other psychological candidates also suggest themselves to various authors as explanatory supplements to the bizarre perceptual experience account of delusion formation. These include appealing to mood and affect as causal factors in the persistence and content variation of delusions (see Gerrans Ch. 4 and Young Ch.2). Meanwhile attributional biases are invoked by some authors to explain why different delusions possess single-theme contents, and failures of self monitoring as well as of attention strike some authors as causally relevant to the persistence or resistance to extinction of some delusions (see Langdon and Coltheart, Ch.8).

As Davies and Coltheart (Ch.1) point out, in recent years there has been a growing realization among theorists of delusions that psychological contributions to delusions form a mixed bag. Perhaps the best way of classifying them is to distinguish those components which figure in the perceptual experiences and those which reflect problems further downstream in cognitive processing, such as failures of probability judgment, attributional biases, and weakened allegiance to background knowledge and belief.

Just as I was finishing reading this book, I had occasion to read a recent issue of The Monist (volume 82 number 4, 1999) devoted to cognitive theories of mental illness. Several papers in this issue, those by John Campbell, Gerrans, Maher, and Young especially, dovetail nicely with chapters in the present volume and are devoted to the topic of delusions. The following picture of delusions is present in this sort of literature, including the present book and the journal issue just mentioned. Scores of other instances of the same picture, both historical and contemporary, can be cited.

Causes of the onset, variation, and persistence of delusions are special. Certain sub-personal aspects of the physical constitution of persons may possess, encode and process information which is relevant to the onset, and so on, of delusions. (See Gerrans, Ch.4) However delusions themselves have personal or conscious level conceptual contents and constituent conceptual structures, which are causally relevant to the onset, and so on, of delusions. A person’s manner of dealing with the content of his or her states of mind contributes to determining whether a delusion occurs, its identity, persistence, and impact on behavior.

Let me illustrate what I mean by the content constituent causes of delusions by means of two brief related examples. Then, I will return quickly to the book.

Compare the following two cases. I am walking the streets of Memphis, attending a philosophical convention, and I spot someone who vividly appears to me to be the Moses of the Old Testament. The bizarre perceptual experience is overwhelming. I return to Birmingham believing that I have seen Moses. I do little or nothing in consequence of this belief. I seem curiously untouched by facts that are incompatible with the existence of Moses. I continue to insist that I saw Moses in Memphis.

Compare that case with the following: My colleague is walking the streets of Cleveland, attending a psychology convention. She bumps into a lamppost. She enters the convention hall, meets the president of the American Psychological Association, and refers to him as Moses. The man is embarrassed. He insists that he is not Moses. She insists that he is Moses. Then, suddenly fatigued, she excuses herself and goes to her room for a nap, after which, fortunately, she forgets the Moses incident, meets the president, and refers to him with his proper name.

Presumably the conceptual content of the first delusion is causally-explanatorily relevant to questions about its onset, persistence, and so on, whereas the content of the second delusion is not. In my case, I have a bizarre perceptual experience with “Moses in Memphis” as content. In my colleague’s case, she hits her head on a lamppost. For me the specific content of the experience plus other content relevant factors (unmentioned in my sketch, but perhaps including my attention to it, content related mood, and so on) are responsible for the delusion and its persistence. In my colleague’s case, “Moses” is not part of the explanatory fabric of the delusion. Her conviction somehow is lamppost impact dependent and perhaps partly for this reason is eliminated, unawares, after a nap.

The authors in the present volume would be committed to understanding my delusional conviction in terms, in part, of the fact that it is a Moses conviction. The very idea of “Moses in Memphis” has something to do with different features of the delusion, including how I acquire it and why it persists. The ‘something’ to which various authors appeal (such as moods, reasoning deficits, and so on) differ in type or emphasis from chapter to chapter, but lampposts (non-conceptual factors), by and large, possess little or no causal-explanatory relevance. Such is the sort of explanatory picture shared by the authors of the present book.

A good book, this, and insightful too. The chapters are well written, and without exception advance discussion on many different fronts. This is not a book to take to the beach, since the writing (except for the Breen chapter) is intricate and without concession to the topically uninformed reader. Still, Pathologies of Belief should enhance any serious and informed reader’s grasp of its topics.

 

 

George Graham, Ph.D., is Chair and Professor, Department of Philosophy, Professor of Psychology, and Associate Director of Cognitive Science, University of Alabama at Birmingham. Graham is the co-author with G. Lynn Stephens of When Self-Consciousness Breaks: Alien Voices and Inserted Thoughts (MIT Press, 2000). Graham may be reached at the following email address: ggraham@uab.edu.

Categories: Philosophical, MentalHealth