You can prove that, in fact, if you were writing a contract, if there was a social planner you'd work more.

事实上你会发现,如果有书面合同,或者有个规划师的话人们会超常发挥

耶鲁公开课 - 博弈论课程节选

Why do you manage to get some cooperation between you and your roommates even without a written contract?

为什么即便没有书面合同,你一样可以和你室友合作得愉快

耶鲁公开课 - 博弈论课程节选

That is before there is any written evidence from the period in which you are interested.

那是一个你所感兴趣,而无任何书面记录的时代

耶鲁公开课 - 古希腊历史简介课程节选

If you go to Provence then, Provencal is a written language.

你要是去普罗旺斯,普罗旺斯方言是书面语

耶鲁公开课 - 1871年后的法国课程节选

Yeah, so maybe even among your roommates, maybe you don't need a contract because you can manage to achieve the same ends, by the fact that you're going to be interacting with the same person, over and over again during your time at Yale.

没错,就算你和室友没有书面协议,你们一样能达到预期的目的,因为在耶鲁大学上学期间,你们总要碰面

耶鲁公开课 - 博弈论课程节选