Circumscribed delusional beliefs can follow brain injury. We suggest that these involve anomalous perceptual experiences created by a deficit to the person's perceptual system, and misinterpretation of these experiences due to biased reasoning. We use the Capgras delusion (the claim that one or more of one's close relatives has been replaced by an exact replica or impostor) to illustrate this argument. Our account maintains that people voicing this delusion suffer an impairment that leads to faces being perceived as drained of (...) their normal affective significance, and an additional reasoning bias that leads them to put greater weight on forming beliefs that are observationally adequate rather than beliefs that are a conservative extension of their existing stock. We show how this position can integrate issues involved in the philosophy and psychology of belief, and examine the scope for mutually beneficial interaction. (shrink)

Brains, it has recently been argued, are essentially prediction machines. They are bundles of cells that support perception and action by constantly attempting to match incoming sensory inputs with top-down expectations or predictions. This is achieved using a hierarchical generative model that aims to minimize prediction error within a bidirectional cascade of cortical processing. Such accounts offer a unifying model of perception and action, illuminate the functional role of attention, and may neatly capture the special contribution of cortical processing to (...) adaptive success. This target article critically examines this approach, concluding that it offers the best clue yet to the shape of a unified science of mind and action. Sections 1 and 2 lay out the key elements and implications of the approach. Section 3 explores a variety of pitfalls and challenges, spanning the evidential, the methodological, and the more properly conceptual. The paper ends (sections 4 and 5) by asking how such approaches might impact our more general vision of mind, experience, and agency. (shrink)

Jennifer Radden has drawn attention to two features of delusion, ambivalence and subjectivity, which are problematic for theories of delusion that treat delusions as empirical beliefs. She argues for an ‘attitude’ theory of delusion. I argue that once the cognitive architecture of delusion formation is properly described the debate between doxastic and attitude theorists loses its edge. That architecture suggests that delusions are produced by activity in the ‘default mode network’ unsupervised by networks required for decontextualized processing. The cognitive properties (...) of these networks explain the features of delusion which generate the debate between doxastic and attitude theorists. (shrink)

This paper contrasts an interactionist account of delusional misidentification with more traditional one- and two-stage models. Unlike the unidirectional nature of these more traditional models, in which the aetiology of the disorder is said to progress from a neurological disruption via an anomalous experience to a delusional belief, the interactionist account posits the interaction of top-down and bottom-up processes to better explain the maintenance of the delusional belief. In addition, it places a greater emphasis on the patient’s underlying phenomenal experience (...) in accounting for the specificity of the delusional content. The role played by patient phenomenology is examined in light of Ratcliffe’s recent phenomenological account. Similarities and differences are discussed. The paper concludes that a purely phenomenological account is unable to differentiate between non-delusional patient groups, who have what appear to be equivalent phenomenal experiences to patients suffering from delusional misidentification but without the delusional belief, and delusional groups, something the interactionist model is able to do. (shrink)

In recent times, explanations of the Capgras delusion have tended to emphasise the cognitive dysfunction that is believed to occur at the second stage of two-stage models. This is generally viewed as a response to the inadequacies of the one-stage account. Whilst accepting that some form of cognitive disruption is a necessary part of the aetiology of the Capgras delusion, I nevertheless argue that the emphasis placed on this second-stage is to the detriment of the important role played by the (...) phenomenology underlying the disorder, both in terms of the formation and maintenance of the delusional belief. This paper therefore proposes an interactionist two-stage model in which the phenomenal experience of the Capgras patient is examined, emphasised, and its relation to top-down processing discussed. (shrink)

Uttered language does not necessarily reflect the planned communications of schizophrenia patients, nor do their delusions necessarily reflect basic failures of inferential reasoning. The role of inhibitory failure in the production of speech and the role of primary experiences of discrepancy between intention and action, and between experience–based expectations and perceived realities account for many of the clinical phenomena that have led to the conclusion that these patients have a ‘thought’ disorder, or a ‘disturbed’ mind. The alternatives and the evidence (...) are summarized in this paper. (shrink)

Anosognosia is literally ‘unawareness of or failure to acknowledge one’s hemi- plegia or other disability’ (OED). Etymology would suggest the meaning ‘lack of knowledge of disease’ so that anosognosia would include any denial of impairment, such as denial of blindness (Anton’s syndrome). But Babinski, who introduced the term in 1914, applied it only to patients with hemiplegia who fail to acknowledge their paralysis. Most commonly, this is failure to acknowledge paralysis of the left side of the body following damage to (...) the right hemisphere of the brain. In this paper, we shall mainly be concerned with anosognosia for hemiplegia. But we shall also use the term ‘anosognosia’ in an inclusive way to encompass lack of knowledge or acknowledgement of any impairment. Indeed, in the construction ‘anosognosia for X’, X might even be anosognosia for some Y. (shrink)

Abstract Studies of irrationality in cognitive psychology have usually looked at areas where humans might be expected to be rational, yet appear not to be. In this paper the other extreme of human irrationality is examined: the delusion as it occurs in psychiatric illness. A parallel is suggested between the delusion as an aberration of cognition and some illusions which result from aberrations within optics. It is argued that, because delusions are found predominantly within certain limited areas of cognitive functioning, (...) they may represent a form of mental aberration which may tell us something about the abstract properties of mind. Possible implications of this model for several areas of cognitive science are discussed. (shrink)

The ‘multicultural clinical interaction’ presents itself as a dilemma for the mental health practitioner. Literature describes two problematic areas where this issues emerges - how to make an adequate distinction between religious rituals and the rituals that may be symptomatic of ‘obsessive compulsive disorder’ (OCD), and how to differentiate ‘normative’ religious or spiritual beliefs, behaviours, and experiences from ‘psychotic’ illnesses. When it comes to understanding service user’s ‘idioms of distress’, beliefs about how culture influences behaviour can create considerable confusion and (...) ‘normative uncertainty’ for mental health practitioners. In the absence of clear diagnostic and assessment criteria on distinguishing between ‘culture’ and ‘psychopathology’, practitioners have had to rely on their own intuition and seek out possible ‘strategies’ or ‘procedures’ from a contradictory and cross-disciplinary evidence base. Decontextualisation of service users’ experiences may result in the pathologisation of culturally ‘normative’ phenomenon, ‘category fallacy’ errors, and poor health care experiences and outcomes for service users. This paper situates this dilemma within a wider debate that has concerned both the biomedical and social sciences, namely, the unresolved question of ‘normality’ or ‘abnormality’. Indeed, issues that arise from dilemmas surrounding the question of ‘culture’ or ‘psychopathology’ are intimately tied to wider cultural ideas about what is considered ‘normal’. The disciplines of psychiatry, psychology, and medical anthropology have struggled to establish workable criteria against which to judge behaviour as ‘normal’, ‘abnormal’, or ‘pathological’. Three models for understanding mental ‘abnormality’ are evident in ‘transcultural psychiatry’ (what is now commonly known as ‘cultural psychiatry’), and these models have corresponded closely to the interpretive models used by anthropologists attempting to make sense of the apparent diversity of human societies. The three models of ‘absolutism’, ‘universalism’ and ‘cultural relativism’ have not only important consequences for the nature and conduct of research enquiry, but also have implications for how the dilemma of ‘culture’ or ‘psychopathology’ is attended to in clinical practice. (shrink)

The standard approach to the core phenomenology of thought insertion characterizes it in terms of a normal sense of thought ownership coupled with an abnormal sense of thought agency. Recently, Fernández (2010) has argued that there are crucial problems with this approach and has proposed instead that what goes wrong fundamentally in such a phenomenology is a sense of thought commitment, characterized in terms of thought endorsement. In this paper, we argue that even though Fernández raises new issues that enrich (...) the topic, his proposal cannot rival the version of the standard approach we shall defend. (shrink)

This article examines the supposedly incomprehensibility of schizophrenic delusions. According to the contemporary classificatory systems (DSM-IV-TR and ICD-10), some delusions typically found in schizophrenia are considered bizarre and incomprehensible. The aim of this article is to discuss the notion of understanding that deems these delusions incomprehensible and to see if it is possible to comprehend these delusions if we apply another notion of understanding. First, I discuss the contemporary schizophrenia definitions and their inherent problems, and I argue that the notion (...) of incomprehensibility in these definitions rests heavily on Jaspers’ notions of understanding and empathy. Secondly, I discuss two Wittgensteinian attempts to comprehend bizarre delusions: (a) Campbell’s proposal to conceive delusions as framework propositions and (b) Sass’s suggestion to interpret delusions in the light of solipsism. Finally, I discuss the phenomenological conception of schizophrenia, which conceives delusion formation as resulting from alterations of the structure of experiencing and from underlying self-disorders. I argue that although a psychological understanding that seeks to grasp meaning in terms of motivations, desires, and other more straightforward psychological connections between mental states is impossible in schizophrenia, we can in fact have a philosophical understanding of the schizophrenic world and of the emergence of delusions typically found in schizophrenia. (shrink)

Delusional misidentification is commonly understood as the product of an inference on the basis of evidence present in the subject's experience. For example, in the Capgras delusion, the patient sees someone who looks like a loved one, but who feels unfamiliar, so they infer that they must not be the loved one. I question this by presenting a distinction between “recognition” and “identification.” Identification does not always require recognition for its epistemic justification, nor does it need recognition for its psychological (...) functioning. Judgments of identification are often the product of a non-inferential mechanism. Delusional misidentification arises as the product of this mechanism malfunctioning. (shrink)

My response to the preceding essays begins with some preliminaries about my terminology, approach, and conception of rationality as a regulative ideal. I then comment on the Murphy's discussion about normal religious belief and religious delusions, and on causal assumptions challenged by Langdon's folies à deux. Responding to Gerrans's imagination-based account of delusion and Hohwy's discussion of illusions, I next try to envision what both doxastic and imagination-based approaches might have overlooked by asking whether there can be delusional feelings. Final (...) comments address the place of phenomenology within Coltheart's two-factor theorizing. (shrink)

The condition known as Multiple Personality Disorder (MPD) or Dissociative Identity Disorder (DID) is metaphysically strange. Can there really be several distinct persons operating in a single body? Our view is that DID sufferers are single persons with a severe mental disorder. In this paper we compare the phenomenology of dissociation between personality states in DID with certain delusional disorders. We argue both that the burden of proof must lie with those who defend the metaphysically extravagant Multiple Persons view and (...) that there is little theoretical motivation to yield to that view in light of the fact that the core symptoms of DID bear remarkable similarity to the symptoms of these other disorders where no such extravagance is ever seriously entertained. (shrink)