Previous: Graphene: The Next Big (But Thin) Thing
Next: SciShow Quiz Show: Dr. Lindsey Doe



View count:422,275
Last sync:2024-04-01 11:30


Citation formatting is not guaranteed to be accurate.
MLA Full: "Why Do We Blush?" YouTube, uploaded by SciShow, 15 July 2014,
MLA Inline: (SciShow, 2014)
APA Full: SciShow. (2014, July 15). Why Do We Blush? [Video]. YouTube.
APA Inline: (SciShow, 2014)
Chicago Full: SciShow, "Why Do We Blush?", July 15, 2014, YouTube, 02:19,
Aw, don't be embarrassed everyone does it! Quick Questions explains what causes blushing, which Darwin called "the most peculiar and most human of all expressions."
Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records:

Or help support us by subscribing to our page on Subbable:
Looking for SciShow elsewhere on the internet?

Thanks Tank Tumblr:


In every culture and every ethnicity around the world, people blush, but animals don't. And it's not just that most animals' faces are covered in fur and feathers and stuff so we can't see them blushing -- they actually don't blush.

Charles Darwin called blushing the most peculiar and most human of all expressions, which is awesome, but why do we blush?

Physiologically, we understand it. I mean, we get the mechanics of why your face turns red when Bernice sneaks up behind you and pulls your pants down in front of the whole rest of the marching band. Bernice!

Anyway, your face turns red because your sympathetic nervous system kicks in. That's the network of nerves that controls your fight or flight response. When it's triggered, it signals the release of adrenaline. Suddenly, your heart rate picks up, and you start breathing faster, and then you're ready to run away. Your pupils dilate, blood rushes to your brain so you can take in as much information as possible, and your blood vessels dilate in a process called vasodilation to improve oxygen flow.

It's basically the same effect you get from warming up before a workout. But in the very hypothetical instance of my pants being pulled down, the blood vessels in my face were responding specifically to a chemical transmitter called adenylyl cyclase. It basically tells the blood vessels in your face to let the adrenaline in.

The weird thing is that these same superficial blood vessels in your face aren't usually affected by sympathetic responses. I mean we don't blush when we're scared. If we did, that might be a sign that blushing served some sort of survival purpose. But it only happens when we're not actually in danger. So, like, why?

Well, some scientists believe that blushing evolved as a social survival trait. When you blush, then the person who's angry at you can see that you're really sorry. The person who's laughing at you can see that you're visibly embarrassed. If that sounds weird, just think about the last time your dog chewed on the furniture, then rolled onto its back when you got mad. Lots of animals have evolved this sort of behavior so they can say, "Hey, whoa, I messed up, I feel terrible."

And it's really hard to stay mad at your dog when it does that. That's how you know it's working. We may never know for sure why blushing became a thing, but it could just be our way of saying "sorry for chewing on the furniture."

Thanks for watching this Quick Questions, especially to our Subbable subscribers who keep these answers coming. To find out how you can support our question answering endeavours, just go to, and if you have a quick question, let us know on Facebook, or on Twitter, or in the comments below, and don't forget to go to and subscribe.