Facial width-to-height ratio underlies perceived dominance on facial emotional expressions

The facial width-to-height ratio (fWHR) is a perceptual cue that affects the perception of psychological traits such as dominance. The current research examined whether the fWHR would impact the perception of dominance and emotional intensity when expressing emotions. In study one, we examined whether the emotional facial expressions (EFEs) modify the visually perceivable fWHR by following a specific pattern reflecting the perception of dominance associated with basic EFEs. We found that EFEs differed from neutral poses following the expected pattern: high dominance EFEs (anger, disgust, happiness) increased the fWHR, whereas low dominance EFEs (fear, sadness, surprise) decreased the fWHR. In study two, we investigated whether manipulating the fWHR (low, average, high) would affect the perception of dominance and emotional intensity. We obtained that the fWHR influenced the perception of dominance and emotional intensity but its effect on dominance was only present with high dominance EFEs. One social implication of this effect is that individuals for which expressing dominant emotions lead to high increase of their fWHR would be perceived highly dominant. We discuss that such effect could participate in the development of individuals' dominance and further researches are still needed to determine its social impact in interaction with other factors.