The temporal connection between smiles and blinks

In this paper, we present evidence for a temporal relationship between eye blinks and smile dynamics (smile onset and offset). Smiles and blinks occur with high frequency during social interaction, yet little is known about their temporal integration. To explore the temporal relationship between them, we used an Active Appearance Models algorithm to detect eye blinks in video sequences that contained manually FACS-coded spontaneous smiles (AU 12). We then computed the temporal distance between blinks and smile onsets and offsets. Our data shows that eye blinks are correlated with the end of the smile and occur close to the offset, but before the lip corners stop moving downwards. Furthermore, a marginally significant effect suggests that eye blinks are suppressed (less frequent) before smile onset. For computer-generated characters, this model of the timing of blinks relative to smiles may be useful in creating compelling facial animations.