这样，我们没个人讲一个笑话，如果这个笑话有一个人没有笑，他就要被扔到河里去。

In this way, we did not personally tell a joke, if there is a joke people do not laugh, he'd be thrown into the river to go.

youdao

不同的巧克力，可以桩上磅，没有笑声的费用，并不影响我们的腰围。

Unlike chocolate, that can pile on the pounds, laughter costs nothing and doesn't affect our waistlines.

youdao

The general story of why we can't in general is because there's no surprise, there's no mock aggression, and also there may be a general deadening of self-stimulation.

为什么大部分人不能胳肢自己,是因为它在我们意料之内，没有打闹的侵略性，通常这种引自己笑的念头都会嘎然而止。

耶鲁公开课 - 心理学导论课程节选