Automatic without autonomic responses to familiar faces: Differential components of covert face recognition in a case of Capgras delusion

Abstract

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 To test this claim a patient with the Capgras delusion (i.e., holding the belief that others have been replaced by impostors, etc.)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.

Psychological processes and paranoia: implications for forensic behavioural science

“…According to this analysis, the Capgras patient recognizes a face as familiar at an intellectual level, but fails to experience the feeling of recognition that normally occurs whenever we encounter someone well known to us. In a test of this hypothesis, Ellis, Lewis, Moselhy, and Young (2000) were able to show that Capgras patients did not exhibit the autonomic response that is normally elicited when viewing a familiar face.…”

Autonomic responses to familiar faces without autonomic responses to familiar voices: Evidence for voice-specific Capgras delusion

“…Following the procedure detailed in Ellis et al (2000), each face was presented for 2 seconds, with an interval of 20 seconds between stimuli. The first five faces were unfamiliar practice faces and were not analysed.…”

“…Specifically, they should show no differential responses for familiar compared with unfamiliar faces. This prediction has been tested by Ellis, Lewis, Moselhy, and Young (2000), Ellis, Young, Quayle, and de Pauw (1997b), and Hirstein and Ramachandran (1997). All these studies found that patients with Capgras delusion produced no differential SCRs to familiar and unfamiliar faces.…”

Delusions: A suitable case for imaging?

“…To answer this question Ellis et al (2000) tested B.P., a 69-year-old woman with Capgras delusion, together with six non-psychiatric controls. Each was given a standard familiar/unfamiliar face SCR test; a self-priming task (names to be classified for familiarity preceded by same face or another's face); and an interference test (incidental faces present while names were classified by occupation).…”