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Department of Cognitive Science

Cognitive Science Alumni

Ryan McKay

Ryan McKay

Thesis Details

'Sleights of mind': Delusions and self-deception.

Delusions are false beliefs, sometimes with bizarre content, that are held with strong conviction even in the presence of contrary evidence and despite the efforts of family, friends and clinicians to dissuade the deluded individual. The multiplicity of conditions that can cause delusions and the variable phenomenology associated with delusions are clinically important and theoretically challenging. Recent years have seen motivational accounts of delusions supplanted by cognitive neuropsychiatric formulations that attribute delusions to brain damage. Cognitive neuropsychiatry aims to develop a model of the processes underlying normal belief generation and evaluation, and to explain delusions in terms of damages to processes implicated in this model of normal functioning. The present research attempts to establish that motivational processes are involved in the genesis and maintenance of at least some delusions. This involves investigating whether one can identify any forms of delusion where a cognitive neuropsychiatric explanation is implausible (or even demonstrably false) whereas a motivational explanation is plausible. If successful, the research will call for an integration of motivational approaches (e.g. psychodynamic and social-cognitive) into current cognitive neuropsychiatric formulations - a theoretical overhaul with potentially significant clinical implications. The research involves three strands: 1) Paranoia and Persecutory Delusions. Research by Richard Bentall, Peter Kinderman and colleagues has suggested that persecutory delusions result from a defensive need to maintain self-esteem which drives a characteristic attributional bias (a tendency to make externalising, personalising attributions for negative events). My research aims to re-investigate this cognitive-motivational formulation using deluded participants and to determine whether these processes also operate in non-clinical populations. Evidence that Bentall and Kinderman's framework encompasses both persecutory delusions and paranoid states in general will provide further support for a model of delusions and non-clinical defensive processes as existing on a continuum of delusional severity. 2) Religious Belief and Delusion. At least since Marx (religion as "the opium of the people") and Freud (religion the "universal obsessional neurosis of humanity"), there has existed a conceptualization of religious belief as pathological. The advent of cognitive neuropsychiatry has heralded a new approach to theorizing about such pathologies of belief, or delusions. The aim of the current research program is to evaluate the historical religion-as-delusion claim from the perspective of a current cognitive neuropsychiatric model of delusion formation and maintenance. The model is known as the "two deficit" or "two factor" model of delusions, and has been developed by Max Coltheart, Martin Davies, Robyn Langdon and Nora Breen at the Macquarie Centre for Cognitive Science (MACCS). This model explains delusions in terms of the conjunction of two factors - the first a neuropsychological deficit which gives rise to an aberrant perception of some kind, and the second a dysfunction in the machinery of belief evaluation that leaves people with the first deficit unable to discount or override the (aberrant) evidence of their senses. Equipped with the new theoretical armament of cognitive neuropsychiatry, and in particular with the empirically accommodating two-factor theory of Coltheart and colleagues, we are in a position to re-evaluate the view that religious belief is pathological, that it represents a breakdown in the mechanisms via which we form and evaluate beliefs. 3) Caloric Vestibular Stimulation, Self-deception and Delusions. Caloric Vestibular Stimulation (CVS) is a routine test of the vestibular system that has been shown to attenuate anosognosic delusions for left-hemiplegia. The primary aim of this research avenue is to investigate whether the CVS technique also attenuates levels of self-serving bias (a social-cognitive measure of self-deception). Such a finding would provide support for a model of delusions as constituting (in some cases at least) extreme outcomes of ordinary (motivated) self-deceptive processes.

  • Type: PhD
  • Scholarship : APA
  • Supervisors : Primary Supervisor (Internal): Max Coltheart. Associate Supervisor (Internal): Robyn Langdon. Associate Supervisor (External): Doris McIlwain


Ryan is also a current member of the ARC Centre of Excellence in Cognition and its Disorders. For more information on Ryan's research please visit their CCD profile.

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