"Far from the heart far from the eye": evidence from the Capgras delusion.

Introduction: Capgras syndrome is characterised by the belief that a significant other has been replaced by an identical-looking impostor. These patients have no difficulties with visual recognition but fail to show a skin conductance response (SCR) to the objects of the delusion. A case of Capgras delusion (YY), specifically characterised by the absence of brain lesions, constituted a good opportunity to test the relationship between SCR hyporesponsiveness and eye movement patterns to familiar and unfamiliar faces.

Methods: Visual scan path and SCR were recorded for YY and 8 controls during the presentation of family members' photographs matched with unfamiliar faces of the same sex, age, and physical likeness. Eye movement patterns were explored by selecting three specific areas of interest (AOI) involving the eyes, the mouth, and the face regions.

Results: In contrast with controls, YY showed a reduction in number and sum of fixation durations to the eyes (p<.01) and no differential SCRs (p>.05) to familiar vs. nonfamiliar faces. SCR and fixation duration to family members' eyes were significantly correlated (r=.77) in both YY and controls.

Conclusions: Eye region exploration seems to be related to the autonomic reactivity elicited by the affective valence of familiar faces.