Seeing red: why do we blush?

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Evolution / Health / Myths / Psychology

Do you blush easily? Many of us blush when we feel embarrassed, ashamed, or nervous, generally when we least want to be noticed. It might happen when you meet someone new, receive a compliment or have to speak in front of a group. Why do our cheeks go red, and why can’t we control it? And do our red cheeks serve any purpose?

Why do we blush? Why do some of us blush more than others? And could blushing actually be useful? Image credit rebecca pedro via Flickr

Why do we blush? Why do some of us blush more than others? And could blushing actually be useful? Image credit rebecca pedro via Flickr

The puzzle of blushing

Back in 1872, Charles Darwin wrote a whole chapter about blushing and concluded:

Blushing is the most peculiar and most human of all expressions. Charles Darwin, The Expression of Emotion in Man and Animals 

Darwin wrote letters to colony administrators and missionaries all over the world to find out the answer to one simple question: do all humans blush? The answer is yes, people of all ethnicities blush, although blushing is less visible on darker skin. Fascinatingly, blushing is one of the things that sets us apart from other animals: unlike most expressions, no equivalent has been found in any animal. It’s not that we can’t see an animal blushing under its fur or feathers; animals just don’t blush.

On the one hand, the process of the skin on our faces turning crimson isn’t terribly complicated. The muscles in the walls of your veins relax and allow more blood to flow. Blood flow to your skin is controlled by the sympathetic nervous system (the part of your nervous system responsible for the fight or flight response). When this part of your nervous system is activated, the hormone adrenaline is released into your system. Adrenaline acts as a stimulant. Your heart rate goes up, your pupils dilate so you can take in as much visual information as possible. Your blood vessels dilate to improve blood flow and maximise the delivery of oxygen to your muscles. You’re all ready to put up a good fight or get the hell out of there.

I’m so embarrassed

But sometimes, the veins in your face also respond to the adrenaline, dilating and letting more blood flow through them than usual. This increased blood flow is responsible for the spreading crimson and warmth we call blushing and we have no conscious control over it. You can’t blush on command and neither can you stop blushing when you want to. The interesting thing is veins don’t normally respond to adrenaline: in other parts of your body, your veins don’t do much in the presence of adrenaline. There are other times when your cheeks may become flushed: after a couple of drinks at the pub or when you’re exercising, but these are different to what we call blushing.

So why do our cheeks go bright red? We don’t know for sure, but we do know there are specific triggers for blushing: we blush when we’re feeling embarrassed, ashamed or exposed. Blushing occurs when we are receiving unwanted social attention. It seems cruel that at the exact moment we wish the floor would swallow us up because we’re so embarrassed, our cheeks turn flame-red, drawing even more attention to ourselves. Fear of blushing (erythrophobia) is a recognised social phobia and causes enormous distress to sufferers. Research has shown people who fear blushing believe they will be judged negatively for blushing. Feeling anxious about being judged means blushing can become a self-fulfilling prophecy. Even being told we are blushing when we’re not can cause many of us to actually blush.

When blushing is a problem

Chronic blushing – when a person blushes more often and more obviously than most of us – is also a debilitating condition. About 5% of the population suffer from it and a quick read of an online support page reveals stories of sufferers feeling unable to leave the house. Chronic blushers blush in normal social situations that wouldn’t usually result in blushing, for example, in response to someone saying their name. There are a few different treatment options for chronic blushers: some sufferers use corrective make-up, others have success with medication, others find relief with cognitive behavioural therapy or hypnotherapy.

A more controversial response is surgery. Bilateral Endoscopic Thoracic Sympathectomy involves cutting the nerves responsible for blushing. These are the nerves that cause the veins in the face to dilate and are usually cut under the armpit. This surgery has mixed reviews: while many patients report it solves their blushing problem, some are unhappy. Because the nerves involved with blushing are also involved in sweating, some patients end up with a different, but equally unsettling problem. Post-surgery, patients are unable to sweat from the face, which can lead to excessive sweating in other parts of the body.

The benefits of blushing

All of this begs the question: why have we evolved to blush? Can there be any benefit to that hot glow of embarrassment most of us have experienced? Research suggests the answer is a definite yes. One study demonstrated we are more likely to trust people who are easily embarrassed. For example, we are far more likely to trust and want to hang out with someone who shows embarrassment rather than pride at being told they’ve done well on a test.

And what of blushing itself? A number of studies point to the fact blushing may have evolved as a way of signaling regret or remorse. Blushing signals we know we’ve done something wrong and we’re sorry. It’s reliable evidence of the fact we genuinely feel bad about having done something wrong because it can’t be faked. Because it’s out of your control, blushing is much more reliable than a verbal ‘sorry’. We trust and forgive people who blush more than those who don’t: a number of researchers believe blushing is an important part of the social glue that keeps human societies functioning.

So next time you feel that familiar warm glow of discomfort, try to remember there is an upside. You’re telling the world you can be trusted.

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  1. Great article. Never thought of bushing from that perspective. It makes me reflect on the last time I blushed…and I can’t remember, so now wondering what that says about me and my trustworthiness 😦
    PS. Sorry for slow response. School hol’s getting the better of my time

    • Thanks, as always for reading and commenting Marti. I’m away at a conference at the moment, so I’m even slower! I still trust you 😀

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