Attentional mechanisms in judging genuine and fake smiles: eye-movement patterns

We investigated the visual attention patterns (i.e., where, when, how frequently, and how long viewers look at each face region) for faces with (a) genuine, enjoyment smiles (i.e., a smiling mouth and happy eyes with the Duchenne marker), (b) fake, nonenjoyment smiles (a smiling mouth but nonhappy eyes: neutral, surprised, fearful, sad, disgusted, or angry), or (c) no smile (and nonhappy eyes). Viewers evaluated whether the faces conveyed happiness ("felt happy") or not, while eye movements were monitored. Results indicated, first, that the smiling mouth captured the first fixation more likely and faster than the eyes, regardless of type of eyes. This reveals similar attentional orienting to genuine and fake smiles. Second, the mouth and, especially, the eyes of faces with fake smiles received more fixations and longer dwell times than those of faces with genuine smiles. This reveals attentional engagement, with a processing cost for fake smiles. Finally, when the mouth of faces with fake smiles was fixated earlier than the eyes, the face was likely to be judged as genuinely happy. This suggests that the first fixation on the smiling mouth biases the viewer to misinterpret the emotional state underlying blended expressions.