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  • Hey, Vsauce. Michael here. And today we're going to talk about

  • yawning.

  • Why do we yawn and why is yawning contagious?

  • How come when I see someone yawn or even think about it it makes me

  • kinda of want to yawn? First things first, definitions.

  • When you yawn, you inhale air and

  • stretch your ear drums. That's why your ears pop when you yawn.

  • Now, if you yawn and at the same time stretch your whole body,

  • that is called pandiculation. A common misconception about

  • yawning is that people yawn when they need more air,

  • more oxygen. But studies have shown that no matter how much

  • oxygen is in the air around a person, they won't yawn more or less frequently.

  • And when people exercise and their bodies do, in fact,

  • need more oxygen, they don't yawn more often.

  • Instead, research has shown that our first answer most likely lies

  • in being cool. When you are

  • exhausted, tired, deep brain

  • temperatures increase, but your brain is like a computer - it operates best

  • at a very specific temperature. And so yawning,

  • bringing all this outside air in through your ears and your mouth,

  • cools your facial blood and actually helps cool down

  • your brain. This phenomenon is particularly easy to observe

  • when parakeets yawn. Researchers have found that parakeets only yawn within a

  • very specific range of temperatures.

  • Too cold outside and yawning will cool the brain too much.

  • Too hot and yawning will actually warm it up. Parakeets are perfect test

  • subjects for this effect,

  • because they yawn just like you and me, except they don't exhibit

  • contagious yawn. If you show a person a video of other people

  • yawning, it's likely that the person watching will yawn

  • his or herself, unless you put an

  • ice pack on their forehead, keeping their brain cooler.

  • Seriously. The University of Albany has found that people contagiously yawn

  • less frequently when they have ice packs on their head,

  • which means that yawning to cool your brain

  • isn't just for the birds. Studies have shown that

  • yawning also increases blood pressure, stretches

  • facial muscles and increases focus.

  • When you panticulate, you stretch

  • all of your muscles, making them better ready to be used

  • at any moment. So when it comes to a herd of prey animals,

  • contagious yawning make sense, because a herd that

  • yawns together stays alert together.

  • Under this theory, yawning is advantageously

  • contagious, because that first animal to yawn

  • acts as a sort of reminder to the rest of the herd to keep themselves

  • ready and alert. But, of course, when we say that yawning is contagious, we don't mean

  • like

  • a disease. Instead, it's a bit more closely related

  • to empathy.

  • Sympathy is when you are concerned for others, where you wish

  • someone was better off. Empathy is the ability to

  • recognize and share the emotions that other people

  • feel. Emotional contagion is when

  • the emotions of people around you influence the way you feel

  • without you even having to separate yourselves from them, like when

  • being around happy people lifts your spirits or how

  • anger and fear can lead to mob mentality. Now,

  • children with autism, who exhibit impaired social interaction and

  • communication,

  • yawn less frequently than other children

  • when viewing videos of people yawning. So,

  • is yawning an emotional contagion or is it about

  • empathy? Well last year, the University of Pisa

  • found that yawn contagiousness is greatest with

  • family and then friends and then

  • acquaintances and lastly strangers.

  • And a study at Leeds University brought in participants to take a test that

  • measured how

  • empathetic they were. But before the test began,

  • amongst them was one person who worked for the researchers

  • and this person yawned every minute for 10 minutes.

  • Interestingly, the people who wound up scoring the highest

  • on the empathy test were also the ones who contagiously yawned along

  • the most. Let's talk more about animal

  • yawning. What fascinates me so much is that animals across many species

  • all yawn, but they do so for different reasons.

  • Animals like guinea pigs and some monkeys yawn

  • to intimidate and show their sharp scary teeth.

  • Some penguins yawn to attract mates and when snakes yawn,

  • it seems to be about realigning their jaws and opening their tracheas

  • to breathe better after a big body disfiguring

  • meal. Fish yawn more frequently when water

  • oxygen levels are low or water heat levels

  • are high. So, when you yawn you're participating in the behavior shared

  • across all kinds of animals,

  • but most likely you're yawning for purposes unique to your species -

  • us humans.

  • What's really cool is that

  • yawning is most likely an ancient signal telling the rest of us humans

  • "let's do this, let's survive."

  • And as always,

  • thanks for watching.

Hey, Vsauce. Michael here. And today we're going to talk about

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