Don't look at my teeth when I smile: Teeth visibility in smiling faces affects emotionality ratings and gaze patterns.

Research on facial emotion processing has offered inconclusive results on whether certain emotional expressions, like happiness, are detected faster over others. A source of discrepancy among studies could stem from differences in physically salient features (e.g., teeth visibility), which are often left uncontrolled in this field of research. In Study 1, happy faces from the Karolinska Database Emotional Databse with visible, normal teeth unexpectedly obtained lower scores on intensity and prototypicality than the same faces with covered teeth. In Study 2, an eye-tracking methodology revealed that although faces with normal teeth drew participants' initial attention, participants spent more time looking at the eye region in faces with covered teeth, a region that previous research had found to be more informative of emotion than the mouth region. Overall, these results suggest that advantages often associated with certain emotional faces might be partially due to artifacts that should be systematically controlled for in future studies. (PsycINFO Database Record (c) 2017 APA, all rights reserved).