Beyond smile dynamics: Mimicry and beliefs in judgments of smiles.

The judgment that a smile is based on "true," usually positive, feelings affects social interaction. However, the processes underlying the interpretation of a smile as being more or less genuine are not well understood. The aim of the present research was to test predictions of the Simulation of Smiles Model (SIMS) proposed by Niedenthal, Mermillod, Maringer, and Hess (2010). In addition to the perceptual features that can guide the judgment of a smile as genuine, the model identifies the conditions that the judgments rely on: (a) the embodiment of the facial expression and its corresponding state, and (b) beliefs about the situations in which genuine smiles are most often expressed. Results of two studies are consistent with the model in that they confirm the hypotheses that facial mimicry provides feedback that is used to judge the meaning of a smile, and that beliefs about the situations in which a smile occurs guides such judgments when mimicry is inhibited.