第1540期:Why do we yawn?

Yawning is something we all do – maybe because we’re bored carrying out tedious tasks or because we’re tired. Sometimes, just seeing other people yawn can set you off. But is this biological function really contagious, and why do we do it in the first place?

打哈欠是我们所有人都会做的事情——也许是因为我们厌倦了执行乏味的任务，或者是因为我们累了。有时，仅仅看到别人打哈欠就会让你反感。但是这种生物学功能真的具有传染性吗？我们为什么要这样做呢？

Many of us think we open our mouths when we yawn to take in more oxygen, but in fact it appears there is no clear biological reason. According to BBC Bitesize, new research suggests it might be because yawning cools the brain down and prevents it from overheating, much like the fan in your laptop. This might be why we’re more likely to feel drowsy and yawn in warm temperatures.

我们中的许多人认为，当我们打哈欠时会张开嘴来吸收更多的氧气，但实际上似乎没有明确的生物学原因。根据 BBC Bitesize 的说法，新的研究表明，这可能是因为打哈欠可以冷却大脑并防止其过热，就像笔记本电脑中的风扇一样。这可能就是我们在温暖的温度下更容易感到困倦和打哈欠的原因。

What is clear is that we yawn more when we’re exhausted and ready for a nap, and we can’t control when we do it – once we start, there’s no stopping us! But it’s also true that yawning is a very contagious behaviour. John Drury, a researcher from Sussex University, told the BBC that “it’s meant to be automatic; it’s something that you can’t stop. Dogs yawn when their owners yawn, animals yawn to each other. It happens whether you want to or not.”

很明显，当我们筋疲力尽准备小睡时，我们会打更多的哈欠，而我们无法控制何时打哈欠——一旦开始，就没有人能阻止我们！但是，打哈欠也是一种非常具有传染性的行为。苏塞克斯大学的研究员约翰·德鲁里告诉 BBC，“它是自动的；这是你无法停止的事情。狗在主人打哈欠时打哈欠，动物互相打哈欠。不管你愿不愿意，它都会发生。”

His research into this cognitive behaviour found that there is a connection with our social group and how close we are to the people in it. If we identify with the person who exhibits the behaviour, we are likely to copy it too.

他对这种认知行为的研究发现，这与我们的社会群体以及我们与其中的人有多亲近有关。如果我们认同表现出这种行为的人，我们也可能会复制它。

Other research by the University of Nottingham in 2017 found similar results. They asked volunteers to watch other people yawn. They found their ability to resist yawning when others around them yawned was limited. And the urge to yawn was increased when people were told they couldn’t. They also found, when using electrical stimulation, that they were able to increase people’s desire to yawn. These findings, they say, could be useful because it could help treat other conditions like Tourette’s, which involve the same area of the brain.

诺丁汉大学 2017 年的其他研究也发现了类似的结果。他们要求志愿者看着其他人打哈欠。当周围的人打哈欠时，他们发现自己抵抗打哈欠的能力是有限的。当人们被告知打哈欠时，打哈欠的冲动就会增加。他们还发现，当使用电刺激时，它们能够增加人们打哈欠的欲望。他们说，这些发现可能很有用，因为它可以帮助治疗像图雷特氏症这样涉及大脑同一区域的其他疾病。

What is certain is that a yawn can creep up on us at any time even when we think we’re not tired – but, I hope, not when you’re reading this article!

可以肯定的是，即使我们认为自己不累，哈欠也可能随时向我们袭来——但是，我希望，当您阅读本文时，不会！

词汇表

yawning 打哈欠
bored 感到无聊的
tired 疲倦的，累的
set sb. off 使某人开始做某事
biological function 生物功能
contagious 有感染力的，会蔓延的
oxygen 氧气
overheat 使……变得过热
drowsy 昏昏欲睡的
exhausted 精疲力尽的
a nap 小睡，打盹
behaviour 行为
automatic 不自觉的，无意识的
cognitive 认知的
identify with sb. 与某人产生共鸣
exhibit 表现出
resist 抗拒
urge 强烈的欲望
electrical stimulation 电刺激
creep up on sb. 不知不觉中体验到，悄悄接近某人