In search of the "Duchenne smile": Evidence from eyemovements

Duchenne de Boulogne (1862/1990) observed that authentic smiles are distinguished from posed smiles by contractions of the orbicularis oculi muscle that surrounds the eye. Hager and Ekman (1985) subsequently reported that the "Duchenne smile" is discriminated specifically by contractions at the outer corners of the eyes ("crows feet" wrinkles). Little is known of the visuo-cognitive strategies that underpin perception of the Duchenne smile. We examined ocular dynamics (pattern of eye fixations) as an overt and accessible index of these strategies (Stark & Ellis, 1981). The spatio-temporal fixation indices were number and duration of foveal fixations to the crows feet area relative to the total face area. In line with predictions, subjects (n = 58) made proportionately more fixations of longer duration to the crows feet area for smiling, compared to negative (sad) and baseline (neutral) control expressions. It is suggested that a "hardwired" response may be involved in reference to this particular anatomical marker of the genuine smile. Humans may have evolved to distinguish the Duchenne smile because of its important communicative role.