Why do we blush?

Blushing is a sudden reddening of the face, neck or upper chest caused by increased blood flow to the skin. It is a normal response to embarrassment, anger, excitement or other strong emotion, according to [medlineplus.gov](https://medlineplus.gov/ency/article/003241.htm). The mechanism is well described. The reason it exists is less settled, and researchers mostly point to a social function. [1]

According to [ist.ac.at](https://www.ist.ac.at/en/news/why-do-we-blush/), the feeling arises in the limbic system, the brain's emotional center, and signals travel to the body through the autonomic nervous system. The sympathetic branch raises the pulse rate and dilates blood vessels in the facial skin so they can take in more blood. [2]

A report in [theconversation.com](https://theconversation.com/why-do-we-blush-turning-red-may-have-surprising-social-benefits-267012) adds that adrenaline is released and the small muscles in vessel walls relax. Adrenaline usually tightens blood vessels, but in the face the vessels widen. The rush of blood near the surface makes the skin red and warm. [distance.physiology.med.ufl.edu](https://distance.physiology.med.ufl.edu/about/articles/physiology/the-science-behind-blushing-from-embarrassment/) likewise describes embarrassment activating the sympathetic system and causing vasodilation. [3] [4]

People of any skin tone blush. The redness is more visible in lighter skin, but the same process occurs in darker skin, and the person still feels warmth or tingling. [3]

One view, reported in [theconversation.com](https://theconversation.com/why-do-we-blush-turning-red-may-have-surprising-social-benefits-267012), is that blushing evolved as a social signal. It shows others that we recognise a mistake, works as a non-verbal apology, and helps maintain social bonds. Because it is involuntary, people tend to read it as honest. [3]

Raymond Crozier of Cardiff University describes a related evolutionary idea in [theconversation.com](https://theconversation.com/explainer-why-do-we-blush-25827). Shame and its accompanying behaviors may be appeasement displays, which signal to dominant individuals that one is not a threat. Such displays are common among primates, and the blush might be the human equivalent. Crozier states that there is no direct evidence for this, and no indication whether the blush serves similar functions across cultures or skin types. He also says research has not reached a consensus on answers. [5]

Experiments offer some support for the social-signal view. People seen blushing after breaking a norm, such as knocking over a pile of cans in a supermarket, tend to be judged less harshly. But work by Peter de Jong and colleagues found that when motives are ambiguous, such as being unable to produce a ticket, a blush can be read as guilt and does not improve how a person is viewed. Context shapes how a blush is interpreted. [5]

Emotion is not the only trigger. MedlinePlus lists high fever, menopause, rosacea and carcinoid syndrome as conditions linked to facial flushing. Other causes include alcohol, certain medicines for diabetes and high cholesterol, exercise, hot or spicy foods, and rapid temperature changes. The [nhs.uk](https://www.nhs.uk/symptoms/blushing/) page notes that blushing is often caused by feeling embarrassed, hot or anxious, and that accompanying symptoms can hint at an underlying cause, such as an overactive thyroid. [1] [6]

Fear of blushing is considered a symptom of social anxiety disorder in psychiatric diagnoses, according to Crozier. [5]