It’s something I’ve learned to live with over the years, but with this acceptance has come curiosity. Why do people blush? What does it mean? And what, if anything, can I do about it?

The science of blushing is straightforward, if not entirely comprehensive. Not much more is known now than it was when Charles Darwin first referred to blushing as “the most peculiar and most human of all expressions,” in The Expression of the Emotions in Man and Animals. Physiologically, blushing occurs when adrenaline causes the capillaries that carry blood to the skin to widen. Many scientists explain blushing in terms of the fight or flight response; people wear the stress of a difficult or confusing situation directly on their faces, in circumstances where throwing a punch or making a run for it aren’t feasible reactions.

For psychologist Ray Crozier, the small amount of information that is known about blushing simply raises more questions. “Blushing is a ubiquitous yet little-understood phenomenon,” he writes in “The Puzzle of Blushing.” “It is a visible change in our most conspicuous feature, yet it can occur when we least want to be noticed and, indeed, can draw attention to our behavior. We redden when we make a faux pas but also when we are praised or thanked. A blush is involuntary and uncontrollable—an actor might simulate a smile, laughter or a frown, but not a blush.”

Regardless of cause, blushing often does serve as a signal or a message to the outside world, Crozier points out—even if it’s a message a person may not be consciously choosing to send. This rings true to me: I see blushing as a loud-mouthed friend who insists on telling the world exactly what you’re thinking, and worse, often explains it badly. Yet in the literary world, at least, blushing’s ambiguity can be an incredibly useful device; a writer can paint a character’s face red and leave readers to figure out the meaning. Blushing appears in everything from Shakespeare, to the Romantic poets, to Rudyard Kipling, whose 17-year-old ingénue in “My Rival” “cannot check” her girlish blush, much to her annoyance.

Even Salman Rushdie in his (perhaps aptly-named) novel Shame includes a character whose “stinky blushes” are so hot they smell of petrol. “She’s a character he imagines as so responsive to the social pressure to blush for others that she blushes for the whole world, says Mary-Ann O’Farrell, the author of Telling Complexions: The Nineteenth-Century English Novel and the Blush. “But literary characters blush not only when they are embarrassed or ashamed but when they feel anger or pain or mortification, when they flirt, when they cover secrets and when they tell them, when they acknowledge love or try to deny that they are feeling it, when they feel the social pressure to behave well and when they notice someone else isn’t.”