国外媒体:人为什么会打呵欠（在线收听）

今天，我们来探讨一下为什么人们会打呵欠。专家们指出， 打呵欠不仅仅是因为你困了。当你对什么事表示担忧，或者有点烦躁，无聊的时候也会打呵欠。

Today, a student from the Caribbean island of Bonaire asks the scientists about something all animals do.

Ziran Chin-On: I’m Ziran, I’m 15 years old and question is why do people yawn?

yamn:呵欠

For an answer, EarthSky asked a neuroscientist at the University of Maryland, Baltimore. He studied yawning for over 30 years – but says why we yawn is still something of a mystery. Here’s Dr. Robert Provine.

Robert Provine: Yawning is a curious behavior because on one level, you can say that we don’t really understand why we do it. So throughout our life, in face, even before birth, we start yawning. And it’s unclear about why we produce this act.

Provine said you might yawn because you’re tired,anxious, or bored.

Robert Provine: What all of these things have in common is a change in state. We’re changing from one kind of mood, one kind of exercise level to another. Yawning may help us through these states by stirring up our physiology.

stirring up adj. 搅拌的(翻料的)，激动人心的

Yawning is also highly contagious – which makes it even more interesting to neuroscientists.

Robert Provine: It gives us insight about how the brain links people together in social patterns.

Scientists at the University of Albany have also suggested that yawning may cool down our brains. Our thanks to Ziran Chin-On and Dr. Robert Provine.

Thanks also to the Monsanto Fund. I am Joel Block from E&S, a clear voice for science. We are at E&S. org.