Clarifying "Familiarity": Examining Differences in the Phenomenal Experiences of Patients Suffering From Prosopagnosia and Capgras Delusion

Current explanations of Capgras delusion, whether one or two stage, tend to accept the view that the Capgras patient suffers from an anomalous, often disturbing, phenomenal experience. These explanations also tend to incorporate Ellis and Young's mirror-image model, in which the neurological dysfunction underlying the Capgras patient's disturbed phenomenal experience is said to mirror that of the prosopagnosic patient. The aim of this paper is not to endorse either a one- or two-stage explanation; nor is it my aim to assess the validity of the mirror-image model. Rather, I intend to highlight discrepancies and ambiguities in the language used to describe the deficits characteristic of prosopagnosia and Capgras delusion, particularly by proponents of the mirror-image model. It is my view that clarification of the word "familiarity" and the phrase "lacking a sense of familiarity" is needed, because both are used to describe quite distinct phenomenal experiences. A closer examination of what is involved in the prosopagnosic and Capgras "experience" should prove useful in explaining the manner in which each respective patient's experience differs. In addition, a more detailed analysis of what is and is not meant by the phrase "lacking a sense of familiarity" should offer greater insight into the nature of the anomalous experience that forms the basis for the Capgras delusion—namely, the what-it-is-likeness of preference, often expressed by the patient as a sense of estrangement.