Blush to judgment

Why do humans alone turn red in the face?

(Cristina Byvik / Union-Tribune photo-illustration)
(Cristina Byvik / Union-Tribune photo-illustration)

In other words, he said, blushing likely moderates bad behavior. And it is a public signal of remorse. If a miscreant blushes with shame or embarrassment, experts say, that is a public admission of wrongdoing and a nonverbal request for forgiveness. Blushing can diffuse tense situations, perhaps reducing the chance of violence, which benefits neither individual nor group. Blushing helps people – and societies – get along.

“The problem with the standard explanation is that people often blush when they have done nothing whatsoever to create problems in the group,” said Mark Leary, director of the social psychology program at Duke University.

“For example, people sometimes blush when complimented, singled out for positive attention, having 'Happy Birthday' sung to them, or merely stared at. My own theory, which I published in the 1990s, suggests that blushing arises from undesired social attention.”

That undesired attention can be negative, such as embarrassment or criticism, or positive, such as lavish praise or excessive visual admiration, or being serenaded when one does not know how to respond, said Leary.

“Blushing seems to signal, 'I'm uncomfortable with the amount of social attention I'm receiving' and actually deter others' attention. People find it hard to continue to look at other people who are blushing.”

But what if the act of blushing isn't apparent? Dark-skinned people blush. What's the benefit of a signal unseen?

“We have two possibilities,” said Christopher Boehm, an anthropologist at the University of Southern California. The first is that blushing is simply an irrelevant physical phenomenon that persists because, while it provides no real value, it doesn't cause harm, either. It's just there – like our appendix.

The second possibility, according to Boehm, is that blushing originated as an internal physiological cue. “The original adaptive function was likely to have been that the burning sensation reminded someone sharply that a deviant act had occurred, which in turn served to inhibit future such acts and reduced the potential reproductive damage society's punitive reactions can bring about.

“If the original population was very dark skinned, this signal would have been private. If it wasn't, it would have been public. In either event, the signal would have assisted people in controlling their deviant tendencies in ways that ultimately were individually adaptive. The advantage of this hypothesis is that it works regardless of skin color and regardless of whether blushing is visible in people with dark skins.”

Red all over

No less confounding is why women appear to blush more easily than men. One notion suggests it's simply a primitive physical cue intended to draw and hold the attention of prospective mates. It's a sign of excitement and arousal.

Darwin and his contemporaries thought so. Blushing was deemed lovely and virtuous. The English novelist Jane Austen (1775-1817) considered it to be an appealing sign of feminine modesty and sincerity. The French Impressionist painter Pierre-Auguste Renoir (1841-1919) favored blushing beauties.

More recently, a Scottish study noted that people find pinker faces to be more appealing than those that are pale or tinged with other colors. Pink, concluded scientists at the University of St. Andrews, suggests health and greater reproductive ability.


