Yet the embarrassed smile is more than just a smile; it has accompanying arabesques, muscle actions in the mouth that alter the appearance of the smile. The most frequent one is the lip press, a sign of inhibition. When people encounter strangers in the street, they often acknowledge each other with this modest smile. Just as common are lip puckers, a faint kiss gracing the embarrassed smile as it unfolds during its two-to-three second attempt to make peace.

This view might make sense for solitary species, like the golden hamster, which flees upon being attacked, or territorial species, like many birds, that rely upon territorial arrangements to avoid deadly conflicts. But many mammals, and in particular primates, need each other to survive. Ostracism and marginalization are tickets to shortened lives. Among humans, individuals who have fewer and less healthy social bonds have been shown to live shorter lives, have compromised immune function, and be more vulnerable to disease. Our sociality, and that of many nonhuman primates, requires a mechanism that brings individuals together in the midst of conflict and aggression.

This offers us insight into the true nature of embarrassment: I have discovered that this subtle display—the averted gaze, the pressed lips—is a sign of our respect for others, our appreciation of their view of things, and our commitment to the moral and social order. Far from reflecting confusion, it turns out that embarrassment can be a peacemaking force that brings people together—both during conflict and after breeches of the social contract, when there’s otherwise great potential for violence and disorder. I’ve even found evidence that facial displays of embarrassment have deep evolutionary roots, and that this seemingly inconsequential emotion provides us with a window into the ethical brain.

Dacher documents his research on embarrassment, an often involuntary emotional response to having committed a social faux pas. People all around the world reflexively signal appeasement when they feel embarrassed, which serves as an unspoken acknowledgement of wrongdoing or having broken a social contract. This submissive, apologetic signal serves to avoid or prevent--rather than invite--conflict.