Why Do We Go Red When We Blush?

Blushing is “the colour of virtue”, according to the Greek philosopher Diogenes (412-323 BC). A quickness to blush can also make you a lousy poker player, and for some people the involuntary reddening of the cheeks, ears, neck and chest can be acutely embarrassing in itself.

So why do people blush when they are suddenly made self-conscious in a social situation?

When we are embarrassed our sympathetic nervous system can trigger the dilation of blood vessels. The skin of the face is richly endowed with capillaries, and increased blood flow can appear as that unstoppable flushing across the cheeks and beyond.

But why would there be such a potentially embarrassing reaction to being embarrassed in the first place? Blushing in some contexts has been suggested as a signal of contrition or genuine regret.

In a study published in the journal Emotionlast year, subjects were asked to read a scenario about a transgression (such as jumping a queue) or an accident (such as spilling a drink on someone) and then rate images of people who were either blushing or not.

Their conclusions? That blushing helps to increase the remedial properties of an embarrassed expression. The researchers write: “Although people often consider blushing to be an undesirable response, our results showed that, in the context of transgressions and mishaps, blushing is a helpful bodily signal with face-saving properties.”