How and why head position changes the perception of facial expressions of emotion.

A large body of research on emotion communication has demonstrated that facial muscle movements (i.e., facial expressions) influence social perceptions made from faces. However, new research suggests that head position can also affect the way that faces are perceived, by systematically changing the appearance of the face. More specifically, according to the action-unit imposter account, tilting one's head downward causes the eyebrows to appear lower and take on a V shape-the same appearance cues associated with a particular facial muscle movement (corrugator activity, or Action Unit 4 [AU4]). Drawing on this account, four studies (two of which were preregistered) tested whether a downward head tilt intensifies perceptions of facial expressions of emotion that include V-shaped eyebrows from AU4 but weaken perceptions of expressions that do not. Supporting this hypothesis, findings showed that (a) when the head is tilted downward, anger expressions-which include V-shaped eyebrows from AU4-are perceived as more intense, whereas expressions of happiness, disgust, fear, and surprise-which do not include V-shaped eyebrows from AU4-are perceived as less intense; (b) visually apparent changes to the eyebrows caused by the action-unit imposter effect account for the effect of a downward head tilt on perceptions of anger; and (c) this head movement is spontaneously used by individuals seeking to encode facial expressions of anger. Together, findings suggest that head movements play an important role in communicating emotion expressions from the face, especially anger. (PsycInfo Database Record (c) 2020 APA, all rights reserved).