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Hadyn D Ellis - One of the best experts on this subject based on the ideXlab platform.
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autonomic responses to familiar faces without autonomic responses to familiar voices evidence for voice specific Capgras Delusion
Cognitive Neuropsychiatry, 2001Co-Authors: Michael Bevan Lewis, Sarah Sherwood, Hamdy Moselhy, Hadyn D EllisAbstract:Introduction: Patients with Capgras Delusion believe that certain individuals have been replaced by duplicates. Unlike normal people, these patients also show reduced autonomic responses to familiar faces, indicating the possibility that it is the covert processes of recognition that are impaired (Ellis, et al., 1997). It has been suggested that such patients would show normal autonomic responses to voices. An auditory parallel of this typical Delusion, therefore, is theoretically possible. That is, a Delusion whereby mis-recognition of the voice produces the Delusional belief of duplication. Such a Delusion would only occur in situations where the person is recognised by voice only; and so, even where it does exist, it would often escape diagnosis. Method: We present here a case, H.L., of what appears to be the Capgras Delusion for voices in a sighted person. This case was investigated using standard skin conductance tests for face and voice recognition. Results: Consistent with this diagnosis, H.L. displays normal autonomic responses for faces but reduced autonomic responses for famous voices. Discussion: H.L. represents a previously unreported form of Capgras Delusion and, further, shows dissociation between autonomic responses to faces and voices. Implications for cognitive models of person recognition are discussed.
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Capgras Delusion a window on face recognition
Trends in Cognitive Sciences, 2001Co-Authors: Hadyn D Ellis, Michael Bevan LewisAbstract:Capgras Delusion is the belief that significant others have been replaced by impostors, robots or aliens. Although it usually occurs within a psychiatric illness, it can also be the result of brain injury or other obviously organic disorder. In contrast to patients with prosopagnosia, who cannot consciously recognize previously familiar faces but display autonomic or covert recognition (measured by skin conductance responses), people with Capgras Delusion do not show differential autonomic activity to familiar compared with unknown faces. This challenges traditional models of the way faces are identified and presents some epistemological questions concerning identity. New data also indicate that, contrary to previous evidence, covert recognition can be fractionated into autonomic and behavioural/cognitive types, which is consistent with a recently proposed modification of the modal face recognition model.
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automatic without autonomic responses to familiar faces differential components of covert face recognition in a case of Capgras Delusion
Cognitive Neuropsychiatry, 2000Co-Authors: Hadyn D Ellis, Michael Bevan Lewis, Hamdy Moselhy, Andrew W YoungAbstract:Introduction. This study was designed to elucidate the relationship between different types of covert face recognition. Some patients with prosopagnosia (i.e., the profound inability to recognise previously familiar faces) nonetheless evince autonomic face recognition (elevated skin-conductance levels to familiar faces) or behavioural indices of covert recognition (i.e., priming; interference effects; matching effects; face-name learning). One prosopagnosic patient revealed both autonomic and behavioural covert face recognition-which suggests they may arise from some common basis. Method. To test this claim a patient with the Capgras Delusion (i.e., holding the belief that others have been replaced by impostors, etc.) was tested on each type of covert face recognition and her results compared with agematched controls. We know that the Capgras Delusion is characterised by good overt or conscious face recognition coupled with the absence of autonomic discrimination between familiar and unfamiliar faces. The question addressed here was whether, compared with age- and gender-matched controls, the patient, B.P., would show neither autonomic nor behavioural covert face recognition. Results. The answer was that, although she showed no autonomic discrimination, her performance on a priming task and a test of face/name interference were normal. The controls, as expected, revealed covert face recognition on both the autonomic and behavioural measures. Conclusions. The results imply in B.P. a clear dissociation between autonomic and behavioural measures of covert face recognition. The theoretical implications of these results are discussed.
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Automatic without autonomic responses to familiar faces: Differential components of implicit face recognition in a case of Capgras Delusion
2000Co-Authors: Hadyn D Ellis, Hamdy Moselhy, Michael B Lewis, Andrew W YoungAbstract:Introduction. This study was designed to elucidatethe relationshipbetween different types of covert face recognition. Some patients with prosopagnosia (i.e., the profound inability to recognise previously familiar faces) nonetheless evince autonomic face recognition (elevated skin-conductance levels to familiar faces) or behavioural indices of covert recognition (i.e., priming; interference effects; matching effects; face-name learning). One prosopagnosic patient revealed both autonomic and behaviouralcovert face recognition-which suggests they may arise from some common basis. Method. To test this claim a patient with the Capgras Delusion (i.e., holding the belief that others have been replaced by impostors, etc.) was tested on each type of covert face recognitionand her results compared with agematched controls. We know that the Capgras Delusion is characterised by good overt or conscious face recognitioncoupled with the absence of autonomic discrimination between familiar and unfamiliar faces. The question addressed here was whether, compared with age-and gender-matched controls, the patient, B.P., would show neither autonomic nor behaviouralcovert face recognition.Results. The answer was that, although she showed no autonomic discrimination, her performance on a priming task and a test of face/name interference were normal. The controls, as expected, revealed covert face recognition on both the autonomic and behavioural measures. Conclusions. The results imply in B.P. a clear dissociation between autonomic and behavioural measures of covert face recognition. The theoretical implications of these results are discussed
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reduced autonomic responses to faces in Capgras Delusion
Proceedings of The Royal Society B: Biological Sciences, 1997Co-Authors: Hadyn D Ellis, Andrew W Young, Angela H Quayle, Karel W De PauwAbstract:People experiencing the Capgras Delusion claim that others, usually those quite close emotionally, have been replaced by near–identical impostors. Ellis and Young suggested in 1990 that the Capgras Delusion results from damage to a neurological system involved in orienting responses to seen faces based on their personal significance. This hypothesis predicts that people suffering the Capgras Delusion will be hyporesponsive to familiar faces. We tested this prediction in five people with Capgras Delusion. Comparison data were obtained from five middle–aged members of the general public, and a psychiatric control group of five patients taking similar anti–psychotic medication. Capgras Delusion patients did not reveal autonomic discrimination between familiar and unfamiliar faces, but orienting responses to auditory tones were normal in magnitude and rate of initial habituation, showing that the hyporesponsiveness is circumscribed.
Michael Bevan Lewis - One of the best experts on this subject based on the ideXlab platform.
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autonomic responses to familiar faces without autonomic responses to familiar voices evidence for voice specific Capgras Delusion
Cognitive Neuropsychiatry, 2001Co-Authors: Michael Bevan Lewis, Sarah Sherwood, Hamdy Moselhy, Hadyn D EllisAbstract:Introduction: Patients with Capgras Delusion believe that certain individuals have been replaced by duplicates. Unlike normal people, these patients also show reduced autonomic responses to familiar faces, indicating the possibility that it is the covert processes of recognition that are impaired (Ellis, et al., 1997). It has been suggested that such patients would show normal autonomic responses to voices. An auditory parallel of this typical Delusion, therefore, is theoretically possible. That is, a Delusion whereby mis-recognition of the voice produces the Delusional belief of duplication. Such a Delusion would only occur in situations where the person is recognised by voice only; and so, even where it does exist, it would often escape diagnosis. Method: We present here a case, H.L., of what appears to be the Capgras Delusion for voices in a sighted person. This case was investigated using standard skin conductance tests for face and voice recognition. Results: Consistent with this diagnosis, H.L. displays normal autonomic responses for faces but reduced autonomic responses for famous voices. Discussion: H.L. represents a previously unreported form of Capgras Delusion and, further, shows dissociation between autonomic responses to faces and voices. Implications for cognitive models of person recognition are discussed.
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Capgras Delusion a window on face recognition
Trends in Cognitive Sciences, 2001Co-Authors: Hadyn D Ellis, Michael Bevan LewisAbstract:Capgras Delusion is the belief that significant others have been replaced by impostors, robots or aliens. Although it usually occurs within a psychiatric illness, it can also be the result of brain injury or other obviously organic disorder. In contrast to patients with prosopagnosia, who cannot consciously recognize previously familiar faces but display autonomic or covert recognition (measured by skin conductance responses), people with Capgras Delusion do not show differential autonomic activity to familiar compared with unknown faces. This challenges traditional models of the way faces are identified and presents some epistemological questions concerning identity. New data also indicate that, contrary to previous evidence, covert recognition can be fractionated into autonomic and behavioural/cognitive types, which is consistent with a recently proposed modification of the modal face recognition model.
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automatic without autonomic responses to familiar faces differential components of covert face recognition in a case of Capgras Delusion
Cognitive Neuropsychiatry, 2000Co-Authors: Hadyn D Ellis, Michael Bevan Lewis, Hamdy Moselhy, Andrew W YoungAbstract:Introduction. This study was designed to elucidate the relationship between different types of covert face recognition. Some patients with prosopagnosia (i.e., the profound inability to recognise previously familiar faces) nonetheless evince autonomic face recognition (elevated skin-conductance levels to familiar faces) or behavioural indices of covert recognition (i.e., priming; interference effects; matching effects; face-name learning). One prosopagnosic patient revealed both autonomic and behavioural covert face recognition-which suggests they may arise from some common basis. Method. To test this claim a patient with the Capgras Delusion (i.e., holding the belief that others have been replaced by impostors, etc.) was tested on each type of covert face recognition and her results compared with agematched controls. We know that the Capgras Delusion is characterised by good overt or conscious face recognition coupled with the absence of autonomic discrimination between familiar and unfamiliar faces. The question addressed here was whether, compared with age- and gender-matched controls, the patient, B.P., would show neither autonomic nor behavioural covert face recognition. Results. The answer was that, although she showed no autonomic discrimination, her performance on a priming task and a test of face/name interference were normal. The controls, as expected, revealed covert face recognition on both the autonomic and behavioural measures. Conclusions. The results imply in B.P. a clear dissociation between autonomic and behavioural measures of covert face recognition. The theoretical implications of these results are discussed.
Garry Young - One of the best experts on this subject based on the ideXlab platform.
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amending the revisionist model of the Capgras Delusion a further argument for the role of patient experience in Delusional belief formation
Avant: Journal of the Philosophical-Interdisciplinary Vanguard, 2014Co-Authors: Garry YoungAbstract:Recent papers on the Capgras Delusion have focused on the role played by subpersonal abductive inference in the formation and maintenance of the Delusional belief. In these accounts, the Delusional belief is posited as the first Delusion-related event of which the patient is conscious. As a consequence, an explanatory role for anomalous patient experience is denied. The aim of this paper is to challenge this revisionist position and to integrate subpersonal inference within a model of the Capgras Delusion which includes a role for experiential content. I argue that the following revisionist claims are problematic: (a) that a fully-formed belief enters consciousness, and (b) that this is the first conscious Delusion-related event. Instead, it is my contention that a Delusional thought (arrived at through subpersonal abductive inference) and an anomalous experience co-occur in consciousness prior to the formation of the Delusional belief. The co-occurrence of thought and anomalous experience overcomes problems with the revisionist position resulting in an account of the Capgras Delusion with greater explanatory efficacy.
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the Capgras Delusion
2013Co-Authors: Garry YoungAbstract:Delusional misidentification is the term used to classify a rare set of psychiatric disorders whose symptomatology involves the formation of specific mono-thematic and circumscribed Delusions which are resistant to revision. The specificity of the Delusional content is a characteristic feature of each respective condition, and a key explanadum. Over the years, a variety of Delusional misidentifications have been reported and added to periodically, albeit with a regularity in keeping with their rarity. Voros, Tenyi, Simon and Trixler (2003), for example, recently reported a new form of Delusional misidentification — Clonal Pluralization of the Self — in which the patient believed he was being cloned as a woman. More common is the Fregoli Delusion in which patients believe that strangers are the same person in disguise. The most commonly reported and discussed example of Delusional misidentification is the Capgras Delusion: typically the belief that at least one family member or friend — some significant other — is an impostor.
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on abductive inference and Delusional belief why there is still a role for patient experience within explanations of Capgras Delusion
Cognitive Neuropsychiatry, 2011Co-Authors: Garry YoungAbstract:This paper aims to examine critically the explanatory model of Delusional belief presented in Coltheart, Menzies, and Sutton's (2010) paper, "Abductive Inference and Delusional Belief". The authors acknowledge that certain aspects of the model are speculative. In return, I speculate over the likelihood that the model's emphasis on subpersonal processing adequately and coherently explains the symptoms (as best we know them) of patients with Delusional misidentification (specifically, the Capgras Delusion) and nondeluded equivalent patient groups. In addition, I offer an account of the Capgras Delusion that is compatible with many of the tenets of Coltheart et al.'s model, but which preserves an important explanatory role for patient experience absent, and erroneously so, I contend, from the aforementioned model. The more integrated explanation I am proposing here also provides a number of pertinent empirical questions and testable hypotheses that could inform future models of Delusional belief.
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Capgras Delusion an interactionist model
Consciousness and Cognition, 2008Co-Authors: Garry YoungAbstract:Abstract In this paper I discuss the role played by disturbed phenomenology in accounting for the formation and maintenance of the Capgras Delusion. Whilst endorsing a two-stage model to explain the condition, I nevertheless argue that traditional accounts prioritise the role played by some form of second-stage cognitive disruption at the expense of the significant contribution made by the patient’s disturbed phenomenology, which is often reduced to such uninformative descriptions as “anomalous” or “strange”. By advocating an interactionist model, I argue that the Delusional belief constitutes an attempt on the part of the patient to explain his/her initially odd and somewhat disturbed phenomenal content (which I refer to as a sense of estrangement) and, moreover, that the Delusion then structures the patient’s experience such that what he/she perceives is an impostor. This fact is used to explain the Delusional belief’s maintenance and resistance to revision. Thus, whilst accepting that second-stage cognitive disruption has a part to play in explaining the Capgras Delusion, the emphasis here is placed on the role played by the patient’s changing phenomenal content and its congruence with the Delusional belief. Unlike traditional two-stage models, which posit a unidirectional progression from experience to belief, the interactionist model advocates a two-way interaction between bottom-up and top-down processes. The application of this model to other Delusional beliefs is also considered.
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Restating the role of phenomenal experience in the formation and maintenance of the Capgras Delusion
Phenomenology and the Cognitive Sciences, 2008Co-Authors: Garry YoungAbstract: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.
Andrew W Young - One of the best experts on this subject based on the ideXlab platform.
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automatic without autonomic responses to familiar faces differential components of covert face recognition in a case of Capgras Delusion
Cognitive Neuropsychiatry, 2000Co-Authors: Hadyn D Ellis, Michael Bevan Lewis, Hamdy Moselhy, Andrew W YoungAbstract:Introduction. This study was designed to elucidate the relationship between different types of covert face recognition. Some patients with prosopagnosia (i.e., the profound inability to recognise previously familiar faces) nonetheless evince autonomic face recognition (elevated skin-conductance levels to familiar faces) or behavioural indices of covert recognition (i.e., priming; interference effects; matching effects; face-name learning). One prosopagnosic patient revealed both autonomic and behavioural covert face recognition-which suggests they may arise from some common basis. Method. To test this claim a patient with the Capgras Delusion (i.e., holding the belief that others have been replaced by impostors, etc.) was tested on each type of covert face recognition and her results compared with agematched controls. We know that the Capgras Delusion is characterised by good overt or conscious face recognition coupled with the absence of autonomic discrimination between familiar and unfamiliar faces. The question addressed here was whether, compared with age- and gender-matched controls, the patient, B.P., would show neither autonomic nor behavioural covert face recognition. Results. The answer was that, although she showed no autonomic discrimination, her performance on a priming task and a test of face/name interference were normal. The controls, as expected, revealed covert face recognition on both the autonomic and behavioural measures. Conclusions. The results imply in B.P. a clear dissociation between autonomic and behavioural measures of covert face recognition. The theoretical implications of these results are discussed.
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Automatic without autonomic responses to familiar faces: Differential components of implicit face recognition in a case of Capgras Delusion
2000Co-Authors: Hadyn D Ellis, Hamdy Moselhy, Michael B Lewis, Andrew W YoungAbstract:Introduction. This study was designed to elucidatethe relationshipbetween different types of covert face recognition. Some patients with prosopagnosia (i.e., the profound inability to recognise previously familiar faces) nonetheless evince autonomic face recognition (elevated skin-conductance levels to familiar faces) or behavioural indices of covert recognition (i.e., priming; interference effects; matching effects; face-name learning). One prosopagnosic patient revealed both autonomic and behaviouralcovert face recognition-which suggests they may arise from some common basis. Method. To test this claim a patient with the Capgras Delusion (i.e., holding the belief that others have been replaced by impostors, etc.) was tested on each type of covert face recognitionand her results compared with agematched controls. We know that the Capgras Delusion is characterised by good overt or conscious face recognitioncoupled with the absence of autonomic discrimination between familiar and unfamiliar faces. The question addressed here was whether, compared with age-and gender-matched controls, the patient, B.P., would show neither autonomic nor behaviouralcovert face recognition.Results. The answer was that, although she showed no autonomic discrimination, her performance on a priming task and a test of face/name interference were normal. The controls, as expected, revealed covert face recognition on both the autonomic and behavioural measures. Conclusions. The results imply in B.P. a clear dissociation between autonomic and behavioural measures of covert face recognition. The theoretical implications of these results are discussed
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reduced autonomic responses to faces in Capgras Delusion
Proceedings of The Royal Society B: Biological Sciences, 1997Co-Authors: Hadyn D Ellis, Andrew W Young, Angela H Quayle, Karel W De PauwAbstract:People experiencing the Capgras Delusion claim that others, usually those quite close emotionally, have been replaced by near–identical impostors. Ellis and Young suggested in 1990 that the Capgras Delusion results from damage to a neurological system involved in orienting responses to seen faces based on their personal significance. This hypothesis predicts that people suffering the Capgras Delusion will be hyporesponsive to familiar faces. We tested this prediction in five people with Capgras Delusion. Comparison data were obtained from five middle–aged members of the general public, and a psychiatric control group of five patients taking similar anti–psychotic medication. Capgras Delusion patients did not reveal autonomic discrimination between familiar and unfamiliar faces, but orienting responses to auditory tones were normal in magnitude and rate of initial habituation, showing that the hyporesponsiveness is circumscribed.
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face processing impairments and the Capgras Delusion
British Journal of Psychiatry, 1993Co-Authors: Andrew W Young, Ian C Reid, Simon Wright, Deborah J HellawellAbstract:Investigations of two cases of the Capgras Delusion found that both patients showed face-processing impairments encompassing identification of familiar faces, recognition of emotional facial expressions, and matching of unfamiliar faces. In neither case was there any impairment of recognition memory for words. These findings are consistent with the idea that the basis of the Capgras Delusion lies in damage to neuro-anatomical pathways responsible for appropriate emotional reactions to familiar visual stimuli. The Delusion would then represent the patient's attempt to make sense of the fact that these visual stimuli no longer have appropriate affective significance.
Arno Villringer - One of the best experts on this subject based on the ideXlab platform.
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Capgras Delusion in posterior cortical atrophy a quantitative multimodal imaging single case study
Frontiers in Aging Neuroscience, 2020Co-Authors: Franziska Albrecht, Tommaso Ballarini, Dominique Leuthold, Angela Legler, Simone Hartwig, Matthias L Schroeter, Solveig Tiepolt, Arno VillringerAbstract:Although Alzheimer's disease presents homogeneous histopathology, it causes several clinical phenotypes depending on brain regions involved. Beside the most abundant memory variant, several atypical variants exist. Among them posterior cortical atrophy (PCA) is associated with severe visuospatial/visuoperceptual deficits in the absence of significant primary ocular disease. Here, we report for the first time a case of Capgras Delusion-a Delusional misidentification syndrome, where patients think that familiar persons are replaced by identical "doubles" or an impostor-in a patient with PCA. The 57-year-old female patient was diagnosed with PCA and developed Capgras Delusion 8 years after first symptoms. The patient did not recognize her husband, misidentified him as a stranger, and perceived him as a threat. Such misidentifications did not happen for other persons. Events could be interrupted by reassuring the husband's identity by the patient's female friend or children. We applied in-depth multimodal neuroimaging phenotyping and used single-subject voxel-based morphometry to identify atrophy changes specifically related to the development of the Capgras Delusion. The latter, based on structural T1 magnetic resonance imaging, revealed progressive gray matter volume decline in occipital and temporoparietal areas, involving more the right than the left hemisphere, especially at the beginning. Correspondingly, the right fusiform gyrus was already affected by atrophy at baseline, whereas the left fusiform gyrus became involved in the further disease course. At baseline, glucose hypometabolism as measured by positron emission tomography (PET) with F18-fluorodesoxyglucose (FDG-PET) was evident in the parietooccipital cortex, more pronounced right-sided, and in the right frontotemporal cortex. Amyloid accumulation as assessed by PET with F18-florbetaben was found in the gray matter of the neocortex indicating underlying Alzheimer's disease. Appearance of the Capgras Delusion was related to atrophy in the right posterior cingulate gyrus/precuneus, as well as right middle frontal gyrus/frontal eye field, supporting right frontal areas as particularly relevant for Capgras Delusion. Atrophy in these regions respectively might affect the default mode and dorsal attention networks as shown by meta-analytical co-activation and resting state functional connectivity analyses. This case elucidates the brain-behavior relationship in PCA and Capgras Delusion.
