Why Do We Yawn?

Have you ever yawned in the middle of an important meeting?

你有没有在重要的会议中途打过哈欠？

Ha, it's so embarrassing, isn't it?

哈，超级尴尬的，对吧？

But don't worry, everybody does it.

不过别担心，每个人都会这样。

Believe it or not, babies even yawn before they're born!

信不信由你，宝宝在出生前就会打哈欠了！

So why do we do it?

那我们为什么会打哈欠呢？

For years, people believed we yawned to get more oxygen.

多年来，人们一直以为打哈欠是为了吸进更多氧气。

It sounds logical, right?

听起来很有道理，对吧？

But scientists actually tested this idea.

但科学家真的验证过这个说法。

They gave people extra oxygen to breathe,

他们让受试者多吸一些氧气，

and guess what? They yawned just as much as before!

你猜怎么着？他们打哈欠的次数跟之前一样多！

So researchers have a newer idea.

所以研究人员提出了一个较新的观点。

A yawn might help to cool down your brain.

打哈欠可能有助于给大脑降温。

You open your mouth wide and take a deep breath.

你会把嘴张得大大的，深深吸一口气。

That cool air and extra blood flow can carry heat away.

那股凉空气和增加的血流能把热量带走。

That might be why we yawn more when our brain gets warm.

这也许就是大脑变热时我们更爱打哈欠的原因。

Pretty cool, right? Literally!

很酷吧？而且是真的能“降温”！

Now, have you noticed that yawns are contagious?

对了，你有没有发现打哈欠会传染？

When one person yawns, people nearby often yawn too.

一个人打哈欠，旁边的人往往也会跟着打。

Scientists think this is connected to how we feel about each other.

科学家认为，这跟我们彼此之间的感情有关。

We catch yawns more from family and friends than from strangers!

比起陌生人，我们更容易被家人和朋友传染哈欠！

So a yawn can be a sweet little sign of connection.

所以，打哈欠也可以是一个温馨的小小亲近信号。

Here's the funny part: even hearing about yawns can start one.

有趣的是，光是听人说起打哈欠，就可能让你打一个。

Hmm, I've said the word "yawn" a lot today...

嗯，我今天说了好多次“哈欠”这个词……

So, be honest... did you just yawn?

那么，老实说……你刚才是不是打哈欠了？

Ha! I knew it!

哈！我就知道！