Facial coloration influences social approach-avoidance through social perception.

Perceptions of others' social characteristics are essential for guiding social behaviour and decision making. Recent research has demonstrated that increased facial redness facilitates both positive (e.g. health, attractiveness, happiness) and negative (e.g. dominance, anger) social evaluations. Given that similar facial colouration can lead to diverging evaluations, it is unclear how people integrate these cues to inform social decisions (e.g. approach-avoidance). We suggest that the influence of facial redness on social perceptions and decisions depends on contextual information, including facial-muscular emotion expressions. We test this hypothesis across two studies where participants view faces either increasing or decreasing redness, evaluate them on a range of social characteristics (i.e. aggressiveness, attractiveness, health, friendliness, dominance) and decide whether to approach or avoid them. Increased facial redness facilitated, and decreased redness impeded (to a greater extent), perceptions of each social characteristic. However, the extent of this influence was moderated by the muscular expression (i.e. neutral, happy, angry). Further, we found that the influence of facial redness on approach-avoidance was largely mediated by evaluations of attractiveness and health. Altogether, the current work provides nuanced insights into facial colouration's role as a social signal that informs social perception and decision making.