Well, here are some basic facts that--

这儿有一些关于笑的基本常识
remember we're trying to think like evolutionary biologists here.

记住我们要努力从进化生物学家的角度看问题
Humans have this universal trait. There's no society without laughter.

笑是人类普遍的特征社会离不开笑
It's early emerging as we saw in those clips.

我们刚在剪辑中看到笑很早就出现了
So, what's it for? What does it do?

这说明了什么笑又有什么作用呢
If it's an accident, what's it an accident from? What properties does it have?

如果是个意外又是什么引起这意外的呢它有什么性质呢
And there are some properties that are important to know.

有几个笑的重要性质我们需要了解
It's social and communicative. Why do we know that? Because it's loud.

就是社会性和交际性我们从何得知的因为它很大声
Laughter is not like hunger. Hunger can be silent.

笑不像饥饿饥饿是无声的
Hunger is not essentially a message to other people

饥饿本来就不是要传递给他人的信息
but when humans – when it involves a loud noise –

但人类发出很大的声音
the reason why we've evolved loud noises is to communicate with other people.

为什么我们要进化出很大声音是因为我们要跟他人交流