耶鲁大学博弈论公开课 - 第1集 导论-五个入门结论

视频全文转录（中英双语）

以下为完整中英双语转录，已加标点。英文在前，中文在后，逐段对照。

由 Groq Whisper 转录 → M2.7 B 方案整文标点 + 分段 → M2.7 段号保留翻译 → 逐段对照。

[段 1]

So this is Game Theory Economics 159. If you’re here for Art History, you’re either in the wrong room or stay anyway. Maybe this is the right room, but this is Game Theory, okay? You should have four handouts. Everyone should have four handouts. There is a legal release form. We’ll talk about it in a minute, about the videoing. There is a syllabus, which is a preliminary syllabus. It’s also online, and there are two games, labelled Game 1 and Game 2. Can I get you all to look at Game 1 and start thinking about it? And while you’re thinking about it, I’m hoping you can multitask a bit, and I’ll describe a bit about the class, and we’ll get a bit of admin under our belts. But please try and look at, if somebody’s not looking at it because they’re using it as a fan here, so look at Game 1 and fill out that form for me, okay? So while you’re filling that out, let me tell you a little bit about what we’re going to be doing here. So what is game theory? Game theory is a method of studying strategic situations. Okay, so what’s a strategic situation? Well, let’s start off with what’s not a strategic situation. In your economics, in your intro economics class in 115 or 110, you saw some pretty good examples of situations that were not strategic.

[译文 1]

这是博弈论经济学159。如果你是来上艺术史的，那你不是走错教室了就是留下来吧。也许这是对的教室，但这是博弈论，明白吗？你们应该有四份材料。每个人都应该有四份材料。有一份法律免责表。我们一会儿会谈到关于录像的事。有一份教学大纲，是一份初步的教学大纲。也在网上，还有两个游戏，标注为游戏1和游戏2。能让大家都看一下游戏1开始思考吗？在你们思考的时候，我希望你们能一心多用，我会介绍一下这门课的情况，我们把一些行政事务理清楚。但请尽量看一下，如果有人没在看而是在当扇子用，那就看一下游戏1帮我填一下那张表，好吗？在你填的时候，让我告诉你们一点我们将要做的事情。什么是博弈论？博弈论是一种研究战略局势的方法。好的，那什么是战略局势？让我们先从什么不是战略局势开始。在你们的经济学中，在你们的115或110入门经济学课上，你们看到了一些相当好的非战略局势的例子。

[段 2]

You saw firms working in perfect competition, right? Firms in perfect competition are price takers. They don’t particularly have to worry about the actions of their competitors. You also saw firms that were monopolists, and monopolists don’t have any competitors to worry about, so that’s not a particularly strategic situation. They’re not price takers,not a particularly strategic situation. They’re not price takers, but they take the demand curve. Is this looking familiar for some of you who can remember doing 115 last year or maybe two years ago for some of you? Everything in between is strategic. So everything that constitutes imperfect competition is a strategic setting. Think about the motor industry, the motor car industry. Ford has to worry about what GM is doing and what Toyota is doing, and for the moment at least what Chrysler is doing, but perhaps not for long. So there’s a small number of firms their actions affect each other. So for a literal definition of what strategic means, it’s a setting where the outcomes that affect you depend on actions, not just on your own actions, but on actions of others. That’s as much as I’m going to say for preview right now. We’re going to come back and see plenty of this over the course of the next semester. So what I want to do is get on to where this applies.

[译文 2]

你们看到在完全竞争下运作的企业，对吧？完全竞争中的企业是价格接受者。他们不必特别担心竞争对手的行为。你们也看到过垄断企业，垄断者没有需要担心的竞争对手，所以这不是一个特别具有战略性的情况。他们不是价格接受者，但也不是特别具有战略性的情况。他们接受需求曲线。对于你们中一些能记得去年或两年前学过115的人来说，这听起来熟悉吗？介于两者之间的一切都是战略性的。因此，构成不完全竞争的一切都是战略环境。想一想汽车行业，汽车制造业。福特必须担心通用汽车和丰田在做什么，至少此刻还有克莱斯勒在做什么，但也许不会持续太久。所以企业数量很少，他们的行动相互影响。所以对于战略的严格定义，这是一个你的结果取决于行动的环境，不仅仅是你的行动，还包括他人的行动。这是我现在要说的预告的全部内容。在接下来的一学期里，我们会经常回顾这些内容。那么我想做的是继续讲解这个方法的应用。

[段 3]

Obviously it applies in economics, but it also applies in politics. And in fact, this class will count as a political science class if you’re a political science major. You should go check with the DUS in political science. Game theory is very important in law these days. So for those of you, for the half of you who are going to end up in law school, this is pretty good training. Game theory is also used in biology, and towards the middle of the semester, we’re actually going to see some examples of game theory as applied to evolution. And not surprisingly, game theory applies to sport. All right? So let’s talk about a bit of anSo let’s talk about a bit of admin. How are you doing on filling out those games? Everyone managing to multitask? Playing in game one? Keep writing. I want to get some admin out of the way and I want to start by getting out of the way what is obviously the elephant in the room. Some of you will have noticed that there’s a camera crew here. Okay? So as some of you probably know, Yale is undergoing an open education project and they’re videoing several classes and the idea of this is to make educational materials available beyond the walls of Yale, in fact on the web internationally. So people in places, maybe places in the US or places miles away, maybe in Timbuktu or wherever, who find it difficult to get educational materials from a local university or whatever, can watch certain lectures from Yale on the web.

[译文 3]

显然它应用于经济学，但也应用于政治。事实上，如果你是政治学专业的，这门课可以作为政治学课程计入。你应该去和political science的DUS核实一下。博弈论在这些日子里在法律领域非常重要。对于你们中一半将进入法学院的人来说，这是相当好的训练。博弈论也用于生物学，在学期中期，我们实际上会看到一些博弈论应用于进化的例子。毫不奇怪，博弈论也应用于体育。好的？那么让我们谈谈一些行政事务。你们填写那些游戏表格进行得怎么样了？每个人都能一心多用吗？玩第一个游戏了吗？继续写。我想把一些行政事务处理掉，我想首先处理掉房间里显而易见的大象。你们中一些人会注意到这里有一个摄制组。好的？正如你们中一些人所知道的，耶鲁正在开展一个开放教育项目，他们正在拍摄几门课程，其目的是让教育资料超越耶鲁的围墙，实际上在国际互联网上。所以美国或远方某些地方的人，也许在廷巴克图或别的什么地方，那些在当地大学获得教育资料困难的人，可以在网上观看耶鲁的某些课程。

[段 4]

Some of you have been in classes that do that before. What’s going to be different about this class is that you’re going to be participating in it. The way we teach this class is we’re going to play games, we’re going to have discussions, we’re going to talk among the class, and you’re going to be learning from each other, and I want you to help people watching at home to be able to learn too. And that means you’re going to be on film, at the very least on mic. So how’s that going to work? Around the room are three TAs holding mics. Let me show you where they are. One here, one here, and one here. When I ask for classroom discussions, I’m going to have one of the TAs go to you with a microphone much like in Donahue or something. Okay? All right? And at certain times you’re going to be seen on film, so the camera is actually going to come around and point in your direction. Now I really want this to happen. I had to argue for this to happen because I really feel that this class isn’t about me. I’m part of the class, obviously, but it’s about you teaching each other and participating. All right? But there’s a catch. The catch is that that means you have to sign that legal release form.

[译文 4]

你们中一些以前可能上过这样做过的课。这门课的不同之处在于你们将参与其中。我们教这门课的方式是，我们将玩游戏，我们将进行讨论，我们将全班讨论，你们将从彼此身上学习，我希望你们帮助在家里观看的人也能学习。这意味着你们至少会在麦克风上出镜。这将如何运作？房间周围有三个助教拿着麦克风。让我告诉你们他们在哪里。一个在这里，一个在这里，一个在这里。当我要求课堂讨论时，我会让其中一个助教拿着麦克风走向你们，就像在Donahue节目中那样。好的吗？好的？在某些时候你们会在镜头中被看到，所以摄像机会转过来指向你们的方向。我真的很想让这发生。我为此进行了争辩，因为我真的觉得这门课不是关于我的。显然我是班级的一部分，但它是关于你们互相教学和参与的。好的？但有一个问题。问题是这意味着你们必须签署那份法律免责表。

[段 5]

So you’ll see that you have in front of you a legal release form, you have to assign it, and what that says is that we can use you being shown in class. Think of this as a bad hair day release form. You can’t sue Yale later if you had a bad hair day. For those of you who are on the run from the FBI, your visas run out, or you’re sitting next to your ex-girlfriend, now would be a good time to put a paper bag over your head. All right. Now, just to get you used to the idea, in every class we’re going to have, I think, the same two people. So Jude is the cameraman. When you all wave to Jude, this is Jude, right? Okay? Okay? And Wes is our audio guy. This is Wes. And I will try and remember not to include Jude and Wes in the classroom discussions, but you should be aware that they’re there. All right? If this is making you nervous, if it’s any consolation, it’s making me very nervous. Okay? So we’ll try and make this class work as smoothly as we can, allowing for this extra thing. Let me just say, no one’s making any money off this. At least, I’m hoping these guys are being paid, but me and the TAs are not being paid.

[译文 5]

你们会看到你们面前有一份法律免责表，你们必须签署它，内容是我们可以使用你们在课堂上的画面。把这当作糟糕发型的免责表吧。如果你们有一天发型不好，你们以后不能起诉耶鲁。对于你们中那些正在躲避FBI的人、签证到期的人、或者坐在前女友旁边的人，现在是把纸袋套在头上的好时机。好的。现在，为了让你们习惯这个想法，在每一堂课上，我想会是同样两个人。Jude是摄影师。当你们都向Jude挥手时，这是Jude，对吧？好的？好的？Wes是我们的音频人员。这是Wes。我会尽量记得不在课堂讨论中包含Jude和Wes，但你们应该知道他们在那里。好的？如果这让你们紧张，如果这能安慰你们的话，这让我非常紧张。好的？所以我们会尽量让这门课尽可能顺利地运行，考虑到这件额外的事情。我只想说，没有人从中赚钱。至少，我希望这些人有报酬，但我和助教们没有报酬。

[段 6]

The aim of this is, I think,and the TAs are not being paid. The aim of this, I think, is a good aim. It’s an educational project, and I’m hoping you’ll help us with it. The one difference it is going to mean is that at times I might hold some of the discussions for the class coming down into this part of the room here to make it a little easier for Jude. Alright, how are we doing now on filling out these forms? Has everyone filled in their strategy for the first game? Not yet. Okay, so let’s go on doing a bit more admin. The thing you mostly care about, I’m guessing is the grades. All right? So how is the grade going to work for this class? 30% of the class will be on problem sets, 30% of the grade, 30% on the midterm, and 40% on the final, so 30, 30, 40. The midterm will be held in class on October 17th. That is also in your syllabus. Please don’t anybody tell me any time after today you didn’t know when the midterm was and therefore it clashes with 17 different things. The midterm is on October 17th, which is a Wednesday, in class. All right? The problem sets. There will be roughly 10 problem sets, and I’ll talk about them more later on when I hand them out.

[译文 6]

这件事的目的，我认为，助教们没有报酬。这件事的目的，我认为，是一个好的目的。这是一个教育项目，我希望你们能帮助我们实现它。它将意味着的一个区别是，有时我可能会把一些课堂讨论带到房间的这个区域来进行，以便让Jude更容易一些。好的，你们现在填写表格进行得怎么样了？每个人都填好第一个游戏的策略了吗？还没有。好的，那么让我们继续做一些行政事务。你们最关心的，我猜是成绩。好的？这门课的成绩将如何计算？30%是问题集，30%是期中考，40%是期末考，也就是30、30、40。期中考将在10月17日的课堂上进行。这也在你们的教学大纲里。请不要有人在今天之后的任何时间告诉我你们不知道期中考是什么时候，因此它和17件不同的事情冲突。期中考是在10月17日，星期三，在课堂上。好的？问题集。大约会有10个问题集，当我发下去的时候会更多地谈到它们。

[段 7]

The first one will go out on Monday, but it will be due 10 days later. Roughly speaking, they’ll be every week. The grade distribution. All right? So this is the rough grade distribution. Roughly speaking, a sixth of the class are going to end up with As. A sixth are going to end up with A-, a sixth are going to end up with B+, a sixth is going to end up with B,are going to end up with B plus, a sixth are going to end up with B, a sixth are going to end up with B minus, and the remaining sixth, if I’ve added that up right, are going to end up with what I guess we’re now calling the presidential grade. Is that right? That’s not literally true. I’m going to squeeze it a bit. I’m going to curve it a bit. So actually slightly fewer than a sixth will get straight A’s, and fewer than a sixth will get C’s and below. We’ll squeeze the middle to make them be more B’s. One thing I can guarantee from past experience in this class is that the median grade will be a B+. The median will fall somewhere in the B+. All right? Now, just as forewarning for people who’ve forgotten what a median is, that means half of you, not approximately half, it means exactly half of you, will be getting something like B+, and below, and half will be getting something like B+, and above.

[译文 7]

第一次作业会在周一布置，但截止日期是10天之后。大致来说，作业大约每周一次。评分分布。好吧？这是大致的评分分布。大致来说，班里六分之一的同学会得A，六分之一会得A-，六分之一会得B+，六分之一会得B，六分之一会得B-，剩下的六分之一——如果我没算错的话——会得到我们现在所谓的总统评分。是这样吗？这不是字面意义上的真实。我会稍微收紧一点。我会稍微调整一下曲线。所以实际上，比六分之一略少的人会得到全A，比六分之一略少的人会得到C及以下。我们会压缩中间部分，让更多人得到B。根据这门课的以往经验，我可以保证的一件事是：中位成绩会是B+。中位数会落在B+附近。好吧？现在，提前提醒一下忘记了中位数是什么意思的人，这意味着你们当中的一半，不是大约一半，而是恰好一半，会得到B+及以下，而另一半会得到B+及以上。

[段 8]

Okay. Now, how are you doing in filling in the forms? Has everyone filled it in yet? Surely we must be pretty close to getting everyone filled in. All right. So, last things to talk about before I actually collect them in. Textbooks. There are textbooks for this class. The main textbook is this one, Dutter’s book, Strategy and Games. If you want a slightly tougher book, more rigorous book, try Joel Watson’s book, Strategies. Both of those books are available at the bookstore. But I want to warn everybody ahead of time, I will not be following the textbook. I regard these books as safety nets. If you don’t understand something that happened in class, you want to reinforce an idea that came up in class.happen in class, you want to reinforce an idea that came up in class, then you should read the relevant chapters in the book, and the syllabus will tell you which chapters to read for each class, or for each week of the class, right? But I will not be following these books religiously at all. In fact, they’re just there as backup. In addition, I strongly recommend people read Thinking Strategically. This is a good bedtime reading.

[译文 8]

好。那么，你们填表的情况怎么样了？大家都填好了吗？应该差不多所有人都填完了吧。好吧，在我实际收表之前，最后要讲的几件事。教材。这门课有教材。主教材是这本，杜特的书，《策略与博弈》。如果你想要一本稍微难一点、更严谨的书，可以试试乔尔·沃森的书，《策略》。这两本书在书店都能买到。但我想提前提醒所有人，我不会严格按照教材来教。我把这些书当作安全网。如果你课堂上没听懂什么东西，你想强化课堂上出现的某个概念，你应该去读书中相关的章节，教学大纲会告诉你每周的课该读哪些章节，对吧？但我绝不会一丝不苟地按照这些书来教。事实上，它们只是备用。另外，我强烈推荐大家读一读《战略思考》。这是很好的睡前读物。

[段 9]

Do any of you suffer from insomnia? it’s very good bedtime reading if you suffer from insomnia it’s a good book and what’s more, there’s going to be a new edition of this book this year and Norton have allowed us to get advanced copies of it so if you don’t buy this book this week I may be able to make the advanced copy of the new edition available for some of you next week I’m not taking a cut of that either there’s no money changing hands there alright, sections are on the syllabus sign up, sorry, on the website sign up as usual, put yourself down on the wait list if you don’t get into the section you want, you probably will get into the section you want once we’re done. Alright, now we must be done with the forms. We done with the forms? Alright, so why don’t we send the TAs with or without mics up and down the aisles and collect in your game number one. Not game number two, just game number one. just while we’re doing that I think the reputation of this class I think if you look at the course evaluations online or whatever is thatthink, if you look at the course evaluations online or whatever, is that this class is reasonably hard, but reasonably fun. All right? So I’m hoping that’s what the reputation of the class is.

[译文 9]

你们有人失眠吗？如果失眠的话，这是很好的睡前读物，这是一本好书，而且更重要的是，这本书今年会出新版，诺顿出版社允许我们拿到提前复印本，所以如果你这周不买这本书，下周我可能可以为你们中的一部分人提供新版的提前复印本。我也不会从中抽成，没有任何金钱交易。好吧，各节的信息在教学大纲上，按通常的方式在网上注册，如果你没能选上想要的节，就把自己放在候补名单上，一旦我们完成选课，你很可能就能选上。好吧，现在表格应该收完了吧。表格收完了吗？好吧，那我们派助教带着或者不带着麦克风在过道里走一走，收回你们的第一号游戏。不是二号游戏，只是一号游戏。就在我们做这个的同时，我想这门课的名声——如果你在网上看课程评价什么的——这门课相当难，但也相当有趣。好吧？所以我希望那就是这门课的名声。

[段 10]

All right? So you shouldn’t, if you think this class is going to be easy, I think it isn’t actually an easy class. It’s actually quite a hard class, but I think I can guarantee it’s going to be a fun class. Now one reason it’s a fun class is the nice thing about teaching game theory, quieten down folks, the nice thing about teaching game theory is you get to play games. That’s exactly what we’ve just been doing now. This is our first game and we’re going to play games throughout the course, sometimes several times a week, sometimes just once a week. We got all these things in? Everyone, hand of the men? So I need to get those counted. Has anyone taken the Yale accounting class? No one has aspirations to be that one person has? I’ll have a TA do it. It’s all right. We’ll have a TA do it. So Kai, can you count those for me? Is that right? Let me read out the game you’ve just played. Game one, a simple grade scheme for the class. Read the following carefully without showing your neighbor what you are doing. Put in the box below either the letter alpha or the letter beta. Think of this as a grade B.the letter beta. Think of this as a grade bid. I will randomly pair your form with another form, and neither you nor your pair will ever know with whom you were paired.

[译文 10]

好。所以如果你认为这门课会很简单，那你就错了，我认为这门课实际上并不简单。它确实是一门相当难的课，但我可以保证它会是一门将很有趣的课。这门将很有趣的原因之一——安静一下各位——教博弈论的一个好处是，你可以玩游戏。这正是我们刚才在做的事。这是我们的第一个游戏，我们将在整个课程中玩游戏，有时候一周好几次，有时候一周一次。我们把这些都准备好了吗？所有人，手举起来？让我数一下。有没有人上过耶鲁的会计课？没有人有这个志向吗？有一个人举手了？我让助教来做。没关系，我们会让助教来做。凯，你能帮我数一下吗？是这样吗？让我把你们刚才玩的游戏读出来。第一号游戏，一个简单的班级评分方案。请仔细阅读以下内容，不要让你旁边的人看到你在做什么。在下面的方框里写下字母alpha或字母beta。可以把这想象成一个B级投标。我会随机将你的表格与另一张表格配对，你和你的配对者都不会知道你们是和谁配对的。

[段 11]

Here’s how the grades may be assigned for the class. Well, they won’t be, but we can pretend. If you put alpha and your pair puts beta, then you will get an A and your pair a C. If you and your pair both put alpha, you’ll both get B minus. If you put beta and your pair puts alpha, you’ll get a C and your pair an A, and if you and your pair both put beta, then you’ll both get B+. So that’s the thing you just filled in. Now before we talk about this, let’s just collect this information in a more useful way. So I’m going to remove this for now. We’ll discuss this in a second, but why don’t we actually record what the game is that we’re playing first. So this is our grade game, and what I’m going to do, since it’s kind of hard to absorb all the information just by reading a paragraph of text, I’m going to make a table to record the information. Okay? So what I’m going to do is I’m going to put me here and my pair, the person I’m randomly paired with here, and alpha and beta, which are the choices I’m going to make here, and on the columns, alpha and beta, the choices my pair is making. And in this table, I’m going to put my grades.My grades.

[译文 11]

以下是这门课可能评定成绩的方式。好吧，实际上不会这样，但我们可以假装一下。如果你写alpha而你的配对者写beta，你就会得到A而你的配对者得到C。如果你和配对者都写alpha，你们两个都会得到B-。如果你写beta而你的配对者写alpha，你会得到C而你的配对者得到A，如果你和配对者都写beta，你们两个都会得到B+。这就是你们刚才填写的内容。现在在我们讨论这个之前，让我们以一种更有用的方式来收集这些信息。所以我现在先把那个拿掉。我们等一下再讨论，但我们为什么不先把我们正在玩的游戏记录下来呢。这是我们的评分游戏，我要做的是，由于仅通过阅读一段文字很难吸收所有信息，我要做一个表格来记录这些信息。好吧？我要这样做：我把我放在这里，我的配对者，也就是随机配对的那个人放在这里，alpha和beta是我要做出的选择，在列上，是alpha和beta，也就是我的配对者做出的选择。在这个表格里，我会放上我的成绩。我的成绩。

[段 12]

So my grades, if we both put alpha, is B minus. If we both put beta, was B plus. If I put alpha and she put a beta, I got an A. And if I put beta and she put an alpha, I got a C. Is that correct? That’s more or less right? Yeah? Okay, well we’re here. Why don’t we do the same for my pair? so this is my grades on the left hand table but now let’s look at what my pair will do what my pair will get so I should warn people sitting at the back that my handwriting is pretty bad that’s one reason for moving forward the other thing I should apologise for at this stage of the class is my accent I will try and improve the handwriting there’s not much I can do about the accent at this stage All right, so once again, if we both put alpha, then my pair gets a B minus. If we both put beta, then we both get a B plus, or in particular, my pair gets a B plus. If I put alpha and my pair puts beta, then she gets a C, and if I put beta and she puts alpha, then she gets an A. All right, so I now have all the information that was on the sheet of paper that you just handed in.

[译文 12]

所以我的成绩，如果我们都写alpha，就是B-。如果我们俩都写beta，就是B+。如果我写alpha而她写beta，我得到A。如果我写beta而她写alpha，我得到C。是这样吗？大致对吧？好的，我们就到这里。为什么我们不为我的配对者做同样的事呢？所以这是我的成绩在左边的表格，但现在让我们看看我的配对者会得到什么。所以我应该提醒坐在后面的人，我的字迹相当差，这是我往前走的其中一个原因。还有一件事我应该在这个阶段道歉的是我的口音，我会尽量改进字迹，至于口音在这个时候我也没什么办法。好吧，再说一遍，如果我们都写alpha，那么我的配对者得到B-。如果我们俩都写beta，那么我们都得到B+，或者具体来说，我的配对者得到B+。如果我写alpha而我的配对者写beta，那么她得到C，如果我写beta而她写alpha，那么她得到A。好吧，我现在有了你们刚才交上来的那张纸上所有的信息。

[段 13]

All right, now there’s another way of organizing this It’s standard in game theory, so we may as well get used to it now on the first day. Rather than drawing two different tables like this,Rather than drawing two different tables like this, what I’m going to do is I’m going to take the second table and superimpose it on top of the first table. Okay, so let me do that and you’ll see what I mean. What I’m going to do is draw a larger table, the same basic structure. I’m choosing alpha and beta on the rows. My pair is choosing alpha and beta on the columns. But now I’m going to put both grades in. so the easy ones are on the diagonal we both get B minus if we both choose alpha we both get B plus if we both choose beta but if I choose alpha and my pair chooses beta I get an A and she gets a C and if I choose beta and she chooses alpha then it’s me who gets the C and it’s her who gets the A so notice what I did here the first grade corresponds to the row player, me in this case, and the second grade in each box corresponds to the column player, my pair in this case. So this is a nice, succinct way of recording what was in the previous two tables.

[译文 13]

好的，现在还有一种组织方式——这是博弈论中的标准做法，所以我们不妨从第一天就开始习惯它。与其像这样画两张不同的表，我打算把第二张表叠加在第一张表上。好，让我来做，你们会明白我的意思。我要画一个更大的表格，保持基本结构。我在行上选择α和β，我的搭档在列上选择α和β。但现在我要把两种成绩都放进去。于是对角线上是最轻松的情况——如果我们都选α，我们都得B−；如果我们都选β，我们都得B+；但如果我选α而我的搭档选β，我得A，她得C；如果我选β而她选α，则我得C，她得A。注意这里我把第一个成绩对应行玩家，也就是我；第二个成绩对应列玩家，也就是我的搭档。于是这成为一种简洁的记录方式，把前两张表的内容都囊括其中。

[段 14]

And this is an outcome matrix. This tells us everything that was in the game. It’s an outcome matrix. Okay, so now seems a good time to start talking about what people did. So, let’s just have a show of hands.so let’s just have a show of hands. How many of you chose alpha? Leave your hands up so that Jude can catch that, so people can see at home, okay? All right, and how many of you chose beta? That’s far more, wave your hands to betas, okay. All right, there’s a beta here, okay. So it looks like a lot of, well we’re going to find out, we’re going to count, but a lot more alphas than betas. Let me try and find out some reasons why people chose. So let me have the alphas up again. so the woman who’s in red here can we get a mic to the is it okay we asked you you’re not on the run from the FBI we can ask you so you chose alpha right so why did you choose alpha I did the square and then realized that my partner had chosen alpha therefore I didn’t choose alpha so I chose alpha alright so you wrote out these squares you realized what your partner was going to do and responded to that Any other reasons for choosing alpha around the room?

[译文 14]

这是一个结果矩阵。它告诉我们游戏中所有信息。这是一个结果矩阵。好，现在似乎是谈论大家做了什么的好时机。那么，让我们举手示意一下吧。选α的有多少人？请把手举高，这样Jude可以统计，家里的人也能看到，好吧？好，选β的有多少人？那多得多，挥挥你们的β手，好吧。好，这里有一个β。好吧，看起来选α的人比选β的多很多——我们稍后会统计。先让我了解一下大家选择的原因。让选α的再举手一次。这位穿红衣服的女士，能把话筒递过去吗？我们之前问过你——你不是被FBI追捕的人，所以我们可以问你——你选了α对吧？那你为什么选α？我算了那个方格，然后发现我的搭档已经选了α，所以我没有选α，而是选了α。好吧，你写出了这些方格，你意识到你的搭档会怎么做，并做出了回应。还有其他在座的人选择α的理由吗？

[段 15]

Can we get the woman in here? Try not to be intimidated by these microphones. They’re just mics. It’s okay. Yeah, yeah. I think where there’s mics with alpha, regardless of what my partner chose, I think there would be better outcomes in choosing… All right, so let me say names a second. So your name was… Courtney. Courtney, and your name was… Claralise. Claralise. So slightly different reasons, same choice, alpha. Clara Lees’ reason for the Clara Lees Statist said no matter what the otherfor the clearly say she said no matter what the other person does she reckon she’d get it to get a better grade if she chose alpha hold that thought a second come back to his clarity clearly come back to Paris in a second as talk to the beat is a second let me just emphasize at this stage there are no wrong answers later on the class the big questions have wrong answers right now there’s no wrong answers I’m a bad reasons but there’s no wrong answer so that the beat is up again as a see the beat is all come on the there was a be the right here you you beat a right You’ve backed off the beta, okay. So how can I get a mic into a beta? Let’s stick in this aisle a bit. Is that a beta right there?

[译文 15]

能让那位女士过来吗？别被这些麦克风吓到，它们只是麦克风。没关系。是的，是的。我认为用α的话，不管我的搭档选什么，选择……会有更好的结果。好吧，让我先报一下名字。你的名字是……Courtney。Courtney，然后你的名字是……Claralise。Claralise。理由略有不同，但都选了α。Clara Lees 的理由是：不管对方怎么做，她觉得如果自己选α，成绩会更好。把这个想法先放一下，稍后我们再回到这个细节。让我在此阶段强调一下，这里没有错误的答案——后面课堂的大问题才有错误答案，现在没有错误的答案，只是理由有好有坏，但答案本身没有对错。β这边请再举手一次——那位在右边的同学，你退后了吗，β是吧？好，我该把话筒递给哪位β呢？让我们往这边过道靠一点。那边那位是β吗？

[段 16]

Are you a beta right there? Can I get the beta in here? Who has the beta in here? Can we get the mic in there? Is that possible? In here? Leave your hand up so… There we go. There we go. Just point towards it. That’s fine. That’s fine. Just speak into it. That’s fine. So the reason, right? Yeah, go ahead. I personally don’t like swings that much, and it’s the B minus B plus range, so I’d much rather prefer that to a swing from A to C. All right, so you’re saying it compresses the range. I’m not sure it does compress the range. I mean, if you chose alpha, you’re swinging from A to B-, you’re swinging from B, you’re choosing from B- to C. I mean, there’s similar kind of ranges, but it’s certainly reasons. Other reasons for choosing… Yeah, the guy in blue here. Yep, yep, here, good. Don’t hold the mic, just let it point at you. It’s fine. Well, I guess I thought we could be more collusive and kind of work together, but I guess not.more collusive and kind of work together, but I guess not. So I chose beta. There’s a star in the background, so I missed the answer. Stand up as soon as we can just hear you. Sorry, say again. Sure, my name’s Travis. I thought we could work together, but I guess not.

[译文 16]

你是β吗？能把β叫进来吗？这里谁有β？能递一下麦克风吗？这样可以吗？把手举起来……好了，好了。指向那边就行。没关系，没关系。对着它说话就行。好的。原因是什么？说吧。请讲。我个人不太喜欢波动，它落在B−到B+的区间，所以我宁愿选择它，而不是在A和C之间波动。好吧，你是说它压缩了波动的范围？我不确定它真的压缩了范围。我的意思是，如果你选α，你就在A到B−之间波动，或者说在B−到C之间波动。大致范围差不多，但确实是有理由的。还有其他选α的理由吗？这位穿蓝衣服的先生。是的，是的，在这里，好。别握着麦克风，让它对着你就好了。好的。我原本以为我们可以更合作、一起工作，但看来不行。我选了β。背景有颗星，我错过了答案。站起来吧，这样我们才能听清。对不起，再说一次。好，我叫Travis。我以为我们可以合作，但还是不行。

[段 17]

All right, all right, good, good. If you had chosen beta, we would all have gotten B pluses, but I guess not. Good. So Travis is giving us a different reason, right? He’s saying that maybe, maybe some of you in the room might actually care about each other’s grades, right? I mean you all know each other in class, you all go to the same college. For example, if we played this game up in the business school, are there any MBA students here today? One or two, right? We played this game up in the business school. I think it’s quite likely we’re going to get a lot of alphas chosen, right? But if we played this game up in, let’s say, the Divinity School, school. And I’m guessing that Travis’s answer is reflecting what you guys are raising here. If you played in the Divinity School, you might think that people in the Divinity School might care about other people’s grades. There might be ethical reasons, perfectly good sensible ethical reasons for choosing Peter in this game. There might be other reasons as well, but that’s perhaps the reason to focus on. And perhaps the lesson I want to draw out of this is that right now, this is not a game. Right now, we have actions, strategies, we want to take and we know what the outcomes are but we’re missing something that will make this a game.

[译文 17]

好吧，好吧，好的，好的。如果你们选了β，我们都会得到B+，但看来没有。好的。所以Travis给出了一个不同的理由，对吧？他说，也许在座的有些人真的在乎彼此的成绩，对吧？我的意思是你们都在同一个班级上课，都上同一所大学。例如，如果我们在商学院玩这个游戏，今天有MBA学生吗？一两个，对吧？我们在商学院玩这个游戏。我认为很可能会出现很多α的选择。但如果我们在这个游戏中，比如，在Divinity School玩的话。我猜测Travis的答案正反映了这儿你们提出的观点。如果在Divinity School玩，你可能会认为Divinity School的人会在意别人的成绩。可能有伦理上的理由，选择Peter在这个游戏里是完全合乎情理的伦理考量。也可能有其他理由，但这可能是值得关注的重点。而我想从这件事中得出的教训是：现在，这还不是一个博弈。现在我们只有行动、策略，我们想采取的行动，我们知道结果，但我们缺少一样东西——这才会使它成为博弈。

[段 18]

What are we missing here? Objectives.game. What are we missing here? We’re missing objectives, we’re missing payoffs, we’re missing what people care about, all right? So we can’t really start analyzing a game until we know what people care about, until we know what the payoffs are. And let’s just say something now which I’ll probably forget to say at any other moment of the class, but today it’s relevant, right? Game theory, me, professors at Yale, cannot tell you what your payoffs should be. They should not tell, I can’t tell you in a useful way what it is that your goals in life should be or whatever. That’s not what Game Theory is about. However, once we know what your payoffs are, once we know what your goals are, perhaps Game Theory can help you get there. So we’ve had two different kind of payoffs mentioned here. We’ve had the kind of payoff where we care about our own grade, and Travis has mentioned the kind of payoff where you might care about other people’s grades. And what we’re going to do today is analyze this game under both those possible payoffs. So to start that off, let’s put up some possible payoffs for the game. And I promise we’ll come back and look at some other payoffs later. We’ll revisit the Divinity School later. All right. So here, once again, is our same matrix with me and my pair choosing actions alpha and beta.

[译文 18]

我们这里缺了什么？目标。博弈。我们缺了什么？我们缺少目标、缺少收益、缺少人们在乎的东西，对吧？因此，除非我们知道人们在乎什么，除非我们知道收益是什么，否则我们无法真正开始分析博弈。现在说一句，我可能以后在其他时候会忘记说，但今天正好相关，对吧？博弈论、我、耶鲁的教授们，都不能告诉你们应该有什么收益。他们不应该——我也没有办法有效地告诉你们人生的目标应该是什么。这不是博弈论的内容。然而，一旦我们知道你们的收益是什么，一旦我们知道你们的目标是什么，博弈论或许可以帮助你们实现它们。这里我们已经提到两类收益：一类是只关心自己的成绩，另一类是Travis提到的可能关心他人成绩的收益。今天我们将在这两种可能的收益下分析这个游戏。首先，让我们列出这个游戏的一些可能的收益。我保证我们以后会回过头来看其他的收益。我们稍后还会再讨论Divinity School。好吧，这里再一次是我们同样的矩阵，我和我的搭档分别选择α和β。

[段 19]

But this time,alpha and beta, but this time I’m going to put numbers in here. And some of you will perhaps recognize these numbers, but that’s not really relevant for now. All right? So what’s the idea here? Well, the first idea is that these numbers represent utiles or utilities. They represent what these people are trying to maximize, what they’re trying to achieve their goals. And the idea, just to compare this to the outcome matrix, is for the person who’s me here, AC yields a payoff of, so AC is this box, so AC yields a payoff of 3, whereas B minus, B minus, yields a payoff of 0, and so on. All right? So what’s the interpretation? This is the first interpretation, the natural interpretation that a lot of you jumped to straight away. These are people, people with these payoffs, are people who only care about their own grades. They prefer an A to a B+, they prefer a B+, to a B-, and they prefer a B- to a C. All right? I’m hoping I’ve got the grades in order, otherwise it’s going to ruin my curve at the end of the year. All right? All right? So these people only care about their own grades. They only care about their own.about their own grades. What do we call people who only care about their own grades?

[译文 19]

但这一次，alpha和beta，但这次我要在这里放上数字。你们中有些可能会认出这些数字，但现在这并不真正相关。好吧？所以这里的想法是什么？嗯，第一个想法是这些数字代表效用或效用。它们代表这些人试图最大化什么，他们试图实现什么目标。想法是，与结果矩阵相比，对于我这里的人来说，AC产生收益，所以AC是这个格子，AC产生3的收益，而B减、B减产生0的收益，以此类推。好吧？那什么是解释？这是第一个解释，很多你们立刻跳到的自然解释。有这些收益的人是只关心自己成绩的人。他们更喜欢A而不是B+，更喜欢B+而不是B-，更喜欢B-而不是C。好吧？我希望我的成绩排序是对的，否则会影响我年底的曲线。好吧？好吧？所以这些人只关心自己的成绩。他们只关心自己的……只关心自己的成绩。我们怎么称呼只关心自己成绩的人？

[段 20]

What’s a good technical term for them? In England, I think we’d refer to these guys, whether it’s technical or not, as evil gifs. These are not perhaps the most moral people in the universe. So now we can ask a different question. Suppose, whether these are actual payoffs or not, pretend they are for now. Right? Suppose these are your payoffs. Now we can ask not what did you do but what should you do. Now we have payoffs I can really switch the question to a normative question what should you do. And let’s come back to was it Clara Elise? Where was Clara Elise before? Let’s get the mic on you again. So just explain what you did and why again. Why I chose alpha? Yeah, stand up a second. That’s okay. You chose alpha. I’m assuming these were roughly your payoffs more or less. You were caring about your grades. Why did you choose alpha? I’m sorry? Why did you choose alpha? Just repeat what you said before. Because I thought the two different payoffs that I could have gotten were highest if I chose alpha. Good, good. So what Clarice is saying, it’s an important idea, is this, and tell me if I’m paraphrasing you incorrectly, but I think this is more or less what you’re saying, is no matter what the other person does, no matter what the pair does, she obtains a higher payoff by choosing alpha.

[译文 20]

他们有什么好的技术术语？在英国，我想我们会称这些人为"邪恶的礼物"，不管这算不算技术术语。这些也许不是宇宙中最道德的人。那么现在我们可以问一个不同的问题。假设，无论这些是否是实际的收益，假装它们现在是。好吧？假设这些是你的收益。现在我们可以问的不是你做了什么，而是你应该做什么。现在我们有了收益，我可以真正将问题转向规范性问题——你应该做什么。让我们回到克拉拉·伊莱斯的那个问题。之前克拉拉·伊莱斯在哪里？让我们再次把麦克风递给你。解释一下你做了什么以及为什么。为什么我选择alpha？站起来一下。没关系。你选择了alpha。我假设这些大致上是你的收益或多或少。你在意你的成绩。为什么你选择alpha？抱歉？为什么你选择alpha？重复一下你之前说的。因为我认为如果我选择alpha，我可以得到的两种不同收益是最高的。好的，好的。所以克莱里斯说的，这是一个重要的想法，是这样的，如果我转述得不对请告诉我，但我认为这大致上就是你说的意思，无论其他人做什么，无论搭档做什么，她选择alpha都能获得更高的收益。

[段 21]

Let’s just see that. If the pair chooses alpha,see that. If the pair chooses alpha and she chooses alpha, then she gets 0. If the pair chooses alpha and she chose beta, she gets minus 1. 0 is bigger than minus 1. If the pair chooses beta, then if she chooses alpha, she gets 3. Beta, she gets 1. And 3 is bigger than 1. So in both cases, no matter what the other person does, she receives a higher payoff from choosing alpha, so she should choose alpha. Has everyone followed that line of reasoning? That’s a stronger line of reasoning than the reasoning we had earlier. So the one I’ve now immediately forgotten the name of in the red shirt, whose name was Courtney. So Courtney also gave a reason for choosing alpha and it was a perfectly good reason for choosing alpha, nothing wrong with it, but notice that this reason is a stronger reason. It kind of implies your reason. All right? All right? So let’s get some definitions down here. I think I can fit it in here. Let’s try and fit it in here. Definition, we say that my strategy alpha strictly dominates strictly dominates my strategy beta if my payoff from alpha is strictly greater than that from beta, and this is the key part of the definition regardless of what others do.

[译文 21]

让我们看看这个。如果搭档选择alpha，她选择alpha，她得到0。如果搭档选择alpha而她选择beta，她得到负1。0大于负1。如果搭档选择beta，那么如果她选择alpha，她得到3。选择beta，她得到1。3大于1。所以在两种情况下，无论其他人做什么，她从选择alpha中获得更高的收益，所以她应该选择alpha。大家都跟上这个推理思路了吗？这比我们之前的推理更强的推理。所以那个我现在立刻忘了名字的穿红衬衫的人，她叫考特尼。考特尼也给出了选择alpha的理由，这是一个选择alpha的非常好的理由，没有任何问题，但请注意这个理由是更强的理由。它包含了你的理由。好吧？好吧？让我们在这里定义一些东西。我想我可以把它放进去。让我们试着把它放进去。定义，我们说我的策略alpha严格支配我的策略beta，如果我从alpha获得的收益严格大于从beta获得的收益，这是定义的关键部分，无论其他人做什么。

[段 22]

Regardless of what others do. So let’s read that back. We say that my strategy alpha strictly dominates my strategy beta if my payoff from alpha is strictly greater than that from beta regardless of what others do. Now, it’s by no means my main aim in this class to teach you jargon. But a few bits of jargon are going to be helpful in allowing the conversation to move forward, and this is certainly one. Evil gets is maybe one too, but this is certainly one. Let’s draw out some lessons from this. Actually, so you can still read that, let me bring down and clean this board. So the first lesson of the class, and there’s going to be lots of lessons, is a lesson that emerges immediately from the definition of a dominated strategy, and it’s this. It’s a lesson.So lesson one of the course is do not play a strictly dominated strategy. All right, so with apologies to Strunk and White, this is the passive form, okay, this dominated, passive voice, do not play a strictly dominated strategy. Why? Someone want to tell me why? Yeah, Ali, do you want to get this guy? Yeah, yeah. Stand up. Yep. This is right. Yeah. Because everyone’s going to pick the dominant outcome and then everyone’s going to get the worst result, the collectively worst result. Yeah, that’s a possible answer. so I’m looking for something more direct here.

[译文 22]

无论其他人做什么。让我们回顾一下。我们说我的策略alpha严格支配我的策略beta，如果我从alpha获得的收益严格大于从beta获得的收益，无论其他人做什么。当然，在我的课堂上，教你们术语绝不是我的主要目标。但一些术语对于让对话向前推进会有所帮助，这肯定是其中之一。“邪恶的礼物"也许也是一个，但这肯定是。让我们从中得出一些教训。实际上，你可以继续读，我把它拉下来清理一下黑板。所以课堂的第一个教训，而且会有很多教训，是一个从被支配策略的定义中立即出现的教训，是这样的。是一个教训。所以课程的第一课是不要玩严格被支配的策略。好吧，所以请原谅斯特伦克和怀特，这是被动形式，好吧，这个被支配的，被动语态，不要玩严格被支配的策略。为什么？谁想告诉我为什么？是的，阿里，你想让这家伙回答吗？是的，是的。站起来。是的。这是正确的。是的。因为每个人都会选择支配性的结果，然后每个人都会得到最差的结果，集体最差的结果。是的，这是一个可能的答案。所以我在寻找更直接的东西。

[段 23]

So we look at the definition of a strictly dominated strategy. I’m saying never play one. What’s a possible reason for that? Can we get the woman there? You always lose? Well, I don’t know. It isn’t about winning and losing. What else could we have? Can we get this guy in the pink down here? Well, the payoffs are lower. The payoffs are lower. Okay, so here’s an abbreviated version of that. I mean, that’s perhaps a little bit… It’s not so much an abbreviation. It’s a little bit longer. the reason I don’t want to play a strictly dominated strategy is becausea strictly dominated strategy is if instead I play the strategy that dominates it, I do better in every case. The reason I never want to play a strictly dominated strategy is if instead I play the strategy that dominates it, whatever anyone else does, I’m doing better than I would have done. Now that’s a pretty convincing argument, that sounds like a convincing argument, it sounds like too obvious even to be worth stating in class, so let me now Now try and shake your faith a little bit in this answer. All right? Somebody was wanted by the FBI, right? Okay. So how about the following argument? Look at the payoff matrix again, and suppose I reason as follows. Suppose I reason and say, if we, me and my pair, both reason this way and choose alpha, then we’ll both get zero.

[译文 23]

所以我们看严格被支配策略的定义。我说永远不要玩它。这可能的理由是什么？我们能让那边那位女士回答吗？你总是输？嗯，我不知道。这不是关于输赢。还有什么？能让这边粉红色衣服的家伙回答吗？收益更低。收益更低。好的，所以这是那个的缩写版。我的意思是这也许有点……这不是一个缩写。它长一点。我不想玩严格被支配策略的原因是，一个严格被支配的策略是，如果我 대신玩支配它的策略，我在每种情况下都做得更好。我永远不想玩严格被支配策略的原因是，如果我 대신玩支配它的策略，无论其他人做什么，我都比原来做得更好。现在这是一个相当有说服力的论点，这听起来像一个有说服力的论点，它听起来太明显了甚至不值得在课堂上说出来，所以让我现在试着动摇一下你们对这个答案的一点信心。好吧？有人被联邦调查局通缉，对吧？好的。那么考虑一下下面的论点？再看收益矩阵，假设我如下推理。假设我推理并说，如果我们、我和我搭档，都这样推理并选择alpha，那么我们都会得到0。

[段 24]

But if we both reason a different way and choose beta, then we’ll both get 1. So I should choose beta. 1 is bigger than 0. I should choose beta. What’s wrong with that argument? And that argument must be wrong because it goes against the lesson of the class. And the lessons of the class are gospel, right? They’re not wrong ever. So what’s wrong with that argument? Yeah, good. That’s good. Yeah, good. Well, because you have to be able to agree. You have to be able to speak to them. But we aren’t allowed to show our partners what we wrote. All right. So it involves some notion of agreeing. involves another notion of agreeing. Sonotion of agreeing, involves some notion of agreeing. So certainly part of the problem here with the reasoning I just gave you, the reasoning that said I should choose beta because if we both reason the same way, we both do better that way, involves some kind of magical reasoning. It’s as if I’m arguing that if I reason this way and reason myself to choosing beta, somehow I’m going to make the rest of you reason the same way too. It’s like I’ve got ESP or I’m some character out of, what is it called, the X-Men. Is that what it’s called? X-Men, right? Now in fact, this may come as a surprise to you, I don’t have ESP and I’m not a character out of the X-Men and so you can’t actually see brainwaves emanating from my head and my reasoning doesn’t affect your reasoning.

[译文 24]

但如果我们都以不同的方式推理并选择beta，那么我们都会得到1。所以我应该选择beta。1大于0。我应该选择beta。那个论点有什么问题？那个论点肯定是错误的，因为它违背了课堂的教训。课堂的教训是福音，对吧？它们永远不会错。那么那个论点有什么问题？是的，好的。那是好的。是的，好的。嗯，因为你必须能够同意。你必须能够和他们交谈。但我们不被允许向搭档展示我们写的东西。好吧。所以它涉及某种同意的概念。涉及另一种同意的概念。某种同意的概念。所以我刚才给你们的那种推理，即我应该选择beta因为如果我们都以同样的方式推理，我们都会做得更好，其中涉及某种神奇推理，这是一个问题的部分。就像我在争辩如果我以这种方式推理并说服自己选择beta，不知怎的我会让你们其他人都以同样的方式推理。这就像我有超感官知觉或者我是X战警里的某个角色。是这样叫的吗？X战警，对吧？事实上，这可能会让你们惊讶，我没有超感官知觉，我不是X战警里的角色，所以你实际上看不到从我脑袋里发出的脑电波，我的推理也不会影响你的推理。

[段 25]

So if I did reason that way and chose beta, I’m not going to affect your choice one way or the other. That’s the first thing that’s wrong with that reasoning. What else is wrong with that reasoning? Yeah, that guy down here. Yeah? Well, the second that you choose beta, then it’s in someone’s best interest to take advantage of you. All right, so someone’s going to take advantage of me, but even more than that, even stronger argument. That’s true, but even a stronger argument. Well, how about this? Even if I could, even if I was that guy in the X-Men or the Matrix or whoever it was who could reason his way into making people do things, even if I could make everyone in the room choose beta by the force of my brainwaves, what should I then do? I should choose alpha. If these are my payoffs, I should go ahead and choose alpha, because So that way I end up getting three. All right? So there’s two things wrong with the argument. One, there’s this magical reasoning aspect, my reasoningOne, there’s this magical reasoning aspect, my reasoning is controlling your actions, that doesn’t happen in the real world, and two, even if that was the case, I’d do better to myself to choose out. All right. So, nevertheless, there’s an element of truth in what I just said.

[译文 25]

所以如果我真的是那样推理并选择 beta，我也不会以任何方式影响你的选择。这是那个推理错误的第一个原因。那个推理还有什么问题？是的，那边那位。对吧？嗯，一旦你选择 beta，就会有人的最佳利益是占你便宜。好吧，所以有人会占我便宜，但远不止于此，还有更强的论证。没错，但还有更强的论证。这样说吧，即使我可以，即使我是 X 战警或黑客帝国里那个能用思维让人们做事的人，即使我能用脑电波让房间里的每个人都选择 beta，我接下来应该怎么做？我应该选择 alpha。如果这是我的收益，我应该选择 alpha，因为这样我最终能得到三。对吧？所以这个论点有两个问题。第一，这个神奇的推理方面，我的推理控制你的行为，这在现实世界中不会发生；第二，即使真是那样，我自己做得更好的方式是选择 alpha。好吧。所以，尽管如此，我刚才说的确实有几分道理。

[段 26]

It’s the fact there’s an element of truth in it that makes it very, you know, it seems like a good argument. The element of truth is this, It is true that by both choosing alpha, we both ended up with B minuses, we both ended up with payoffs of 0, rather than payoffs of 1. It is true that by both following this lesson and not choosing the dominated strategy beta, we ended up with payoffs 0, 0 that were bad. And that’s probably the second lesson of the class. so lesson two and this lesson probably wouldn’t be worth stating if it wasn’t for sort of a century of thought and economics that said the opposite so rational choice in this case people not choosing a dominated strategy people choosing a dominant strategy rational choice can lead to outcomes that what do Americans call this that suck. That suck. All right? If you want a more technical term for that, and you remember this from…If you want a more technical term for that, and you remember this from Economics 115, it can lead to outcomes that are inefficient, that are Pareto inefficient. A bit of suck will do for today. Rational choice by rational players can lead to bad outcomes. Okay? So, this is a famous example for this reason. It’s a good illustration of this point. It’s a famous example.

[译文 26]

正是这个几分道理让它看起来像一个好的论点。这份道理是这样的：通过双方都选择 alpha，我们都得到了 B-，我们的收益都是 0，而不是收益 1。这是真的：通过都遵循这个教训，不选择被支配的策略 beta，我们最终得到了 0、0 的糟糕收益。这可能是这堂课的第二课。所以第二个教训——如果不是因为经济学领域大约一个世纪以来的思想说了相反的话，这个教训可能不值得提出来。理性选择，在这种情况下人们不选择被支配的策略，人们选择占优策略，理性选择会导致什么样的结果——美国人怎么称呼这个来着——很糟糕的结果。很糟糕。如果你想用更专业的术语，你从经济学 115 记得的话，就是它可能导致低效的结果，即帕累托低效。今天说一点点糟糕就够了。理性玩家的理性选择可能导致糟糕的结果。对吧？所以，这是一个著名的例子，原因就在于此。它很好地说明了这个观点。它是一个著名的例子。

[段 27]

What’s the name of this example, somebody? This is called Prisoner’s Dilemma. How many of you have heard of the Prisoner’s Dilemma before? Most of you saw it in 115. Why is it called the Prisoner’s Dilemma? yeah so the guy here in orange it’s okay it can just point at you it’s fine I think it’s whether or not the prisoners cooperate in the sentence they have and if they kind of read out the other person then they can have less but if they read out then they end up losing large scale good so in the standard story you’ve got these two crooks or two accused crooks and they’re in separate cells and they’re being interviewed separately kept apart and they’re both told that if neither of them rats the other guy out, they’ll go to jail for, say, a year. If they both rat each other out, they’ll end up in jail for two years. But if you rat the other guy out and he doesn’t rat you out, then you’ll go home free and he’ll go to jail for five years. And you put that all down, you pretty quickly see that regardless whether the other guy rats you out or not, you’re better off ratting him out. All right? Now, if you haven’t ever seen that prisoner’s dilemma, you can see it pretty much every night on a show called Law and Order.

[译文 27]

这个例子叫什么名字，有人知道吗？这叫做囚徒困境。你们有多少人之前听说过囚徒困境？你们大多数人在 115 课程里见过它。为什么叫囚徒困境？是的，这里穿橙色衣服的家伙没问题可以指你我觉得没关系这取决于囚犯在判决中是否合作，如果他们互相揭发对方就可以少判一点，但如果他们互相揭发就会损失很大所以在标准故事里你们有两个罪犯或两个被指控的罪犯他们在不同的牢房里被分开审问他们被分别告知如果他们两个都不揭发对方他们将被监禁比如说一年。如果他们互相揭发他们将被监禁两年。但如果你揭发对方而他不揭发你，你就会无罪释放而他将被监禁五年。你把这些都写下来，很快就会发现不管对方是否揭发你，你最好都揭发他。对吧？如果你从来没看过那个囚徒困境，你几乎每晚都可以在一个叫做《法律与秩序》的节目里看到它。

[段 28]

How many of you have seen Law and Order? If you haven’t seen Law and Order, the way to see Law and Order is to go to a random TV set at a random time and turn on a random channel. This happens in every single episode. So much so that if any of you actually, I mean, this might happen true at Yale, if any of you, or the TV guys, if any of you know the guy who writes the plots for this, have him come to the class, so I get to see the video now, and we can get some better plot lines in there. But of course, that’s not the only example. The grade game and this is not the only example. There are lots of examples of prisoner’s dilemmas out there. Let’s try and find some other ones. So how many of you have roommates in your college? How many of you have roommates? Most of you have roommates, right? So I’m guessing now, but I won’t make you show your hands, because it’s probably embarrassing, but what is the state of your dorm rooms, your shared dorm rooms at the end of the semester, or the end of the school year. So I’m just guessing, having been in a few of these things over the years, that by the end of the semester or certainly by the end of the school year, the state of the average Yale dorm room is quite disgusting.

[译文 28]

你们有多少人看过《法律与秩序》？如果你没看过《法律与秩序》，看它的方法是随便找个时间随便打开一个频道。这在每一集里都会发生。严重到如果你们任何人——我的意思是这可能在耶鲁是真的——如果你们任何人，或者电视圈的人，如果你们任何人认识写这个剧情的家伙，让他来上课，这样我现在就能看到视频了，我们就能得到一些更好的剧情线。但当然，那不是唯一的例子。评分博弈这不是唯一的例子。那里有很多囚徒困境的例子。让我们试着找一些其他的。你们有多少人在大学有室友？有多少人有室友？你们大多数人有室友，对吧？所以我猜一下，但我不会让你们举手，因为可能很尴尬，但是你们宿舍，你们共享的宿舍在学期末或学年末是什么状态。我只是猜一下，这些年来见过一些这种情况，在学期末或者肯定在学年末，耶鲁平均水平的宿舍状态是相当恶心的。

[段 29]

Why is it disgusting? Why is it disgusting? It’s disgusting because people don’t tidy up. They don’t clean up those bits of pizza and bits of chewed bread and cheese. But why don’t they tidy up? Well, let’s just work it out. What would you like to happen if you’re sharing a dorm room? You’d like to have the other guy tidy up, right? The best thing for you is to have the otherguy tidy up, right? The best thing for you is to have the other guy tidy up, and the worst thing for you is to tidy up for the other guy. But now work it out, it’s a prisoner’s dilemma. If the other guy doesn’t tidy up, you’re best off not tidying up either, because the last thing you want is to be tidying up for the other guy, and if the other guy does tidy up, hey, the room’s clean, who cares? Right? So either way, you’re not going to tidy up and you end up with a typical Yale dorm room. Am I being unfair? Are your dorm rooms all perfect? This may be a gender thing, but we’re not going to go there. All right? So there are lots of prisoners’ lemmas out there. Anyone got any other examples? Other examples? Divorce. Divorce. I didn’t quite hear that. Sorry. Let’s try and get a mic on it so we can really hear it.

[译文 29]

为什么恶心？为什么恶心？恶心是因为人们不收拾。他们不清理那些披萨碎屑和面包屑和奶酪。但为什么不收拾？好吧，让我们算一下。如果你们共用一个宿舍，你希望发生什么？你希望另一个人收拾，对吧？对你来说最好的事情是让另一个人收拾，对吧？对你来说最坏的事情是为另一个人收拾。但现在算一下，这是一个囚徒困境。如果另一个人不收拾，你最好的选择也是不收拾，因为你最不想做的事情就是为另一个人收拾，而如果另一个人真的收拾了，嘿，房间干净了，谁在乎呢？所以不管怎样，你都不会收拾，然后你就得到一个典型的耶鲁宿舍。我这样说不公平吗？你们的宿舍都很完美吗？这可能是个性别问题，但我们不往那边走。好吧？所以有很多囚徒困境的例子。有人有其他的例子吗？其他例子？离婚。离婚。我没太听清。抱歉。让我们把麦克风递过来这样我们真的能听到。

[段 30]

Divorce. You’re hiring a lawyer and not paying them a lot of money. OK, and divorce struggles. OK, OK. That’s OK. You’re too young to worry about such things, but never mind. Yeah, OK, that’s a good example. That’s all right. Hiring lawyers, bringing in big guns. What about an economics example? What about firms who are competing in prices? Both firms have an incentive to undercut the other firm, driving down profits for both. The last thing you want is to have the other firm undercut you, in the sense to push prices down. That’s good for us, the consumers, but bad for the firm, bad for industry profit. What remedies do we see? We’ll come back to this later on in the class, but let’s have a preview. So what remedies do we see in society for prisoner’s dilemmas? What kind of remedies we see? Let me try and get the guy here and right in front of you.Let’s get the guy here and right in front of you. Collusion? Yeah, go ahead. Collusion? Collusion. Okay, so firms could collude, all right. So what prevents them from colluding? What prevents them from colluding? So one thing they could do, presumably, is they could write a contract, these firms. They could say, I won’t lower my prices if you don’t lower your prices, and they could put this contract in with the pricey lawyer who’s taking his day off from the divorce court, and that would secure that they wouldn’t lower prices on each other.

[译文 30]

离婚。你雇了一个律师但没付很多钱。好吧，离婚争斗。好吧好吧。这没关系。你太年轻了不用担心这些事情，但没关系。是的，好吧，这是一个好例子。没关系。雇律师，请来大人物。经济学的例子呢？竞争价格的公司呢？两家公司都有压低对方价格的动机，导致双方的利润都下降。你最不想做的事情就是让对方压低你的价格，这样对我们消费者有好处，但对公司不好，对行业利润不好。我们看到什么补救措施？我们这节课后面会再回来讨论这个，但让我们先预览一下。所以我们在社会中看到什么样的囚徒困境补救措施？我们看到什么样的补救措施？让我试着找这边这位，就在你们面前的。串通？是的，请说。串通？串通。好吧，所以公司可以串通，对吧。什么阻止他们串通？什么阻止他们串通？所以他们可能做的一件事情是，他们可以签一份合同，这些公司。他们可以说，如果你不降低我的价格，我就不降低我的价格，他们可以把这份合同交给那个从离婚法庭休息一天来的收费昂贵的律师，这样就能确保他们不会互相降价。

[段 31]

Is that right? So why wouldn’t that work? Why wouldn’t writing a contract here work? It’s against the law, right? It’s a legal contract. It’s not a legal contract. What about you with your roommates? How many of you have a written contract stuck with a magnet on the fridge telling you when you’re supposed to tidy up? Very few of you, right? Why do you manage to get some cooperation between you and your roommates even without a written contract? It’s not legally enforced. Well, it probably is legally enforceable, actually. This guy says it’s not. It probably is legally enforceable. You probably could have a written contract about tidying up. Yeah, the woman in here, yeah. Repetition, you do it over and over? Yeah, so maybe, maybe even among your roommates, maybe you don’t need a contract because you can manage to achieve the same end by the fact that you’re going to be interacting with the same person over and over again during a time at Yale. So we’ll come back and revisit the idea that repeating an interaction may allow you to attain cooperation, BUT WE’RE NOT GOING TO COME BACKallow you to attain cooperation, but we’re not going to come back to that until after the midterm. That’s way down the road, but we’ll get there. Now one person earlier on had mentioned something about communication.

[译文 31]

对吧？那为什么这不起作用？为什么写一份合同在这里不起作用？这是违法的，对吧？这是一份法律合同。这不是一份法律合同。你们和室友之间呢？你们中有多少人在冰箱上用磁铁贴着一份书面合同，告诉你们什么时候应该打扫卫生？你们中很少有人这样做，对吧？为什么你们在没有书面合同的情况下仍然能够与室友合作？它没有法律强制力。嗯，实际上它可能是可以法律执行的。这个家伙说不是。它可能是可以法律执行的。你可能可以写一份关于打扫卫生的合同。是的，这里的那位女士，是的。重复，你一次又一次地做？是的，所以也许，也许甚至在你们室友之间，你可能不需要合同，因为你可以通过在耶鲁的这段时间里与同一个人反复互动来达到同样的目的。所以我们会回来重新审视这个观点，即重复互动可能让你获得合作，但我们要到期中考试之后才会回到这个话题。那还很遥远，但我们会到的。之前有一个人提到了关于沟通的问题。

[段 32]

I think it was somebody in the front, right? So let’s just think about this a second. Is communication the problem here? Is the reason people behave badly in this, or badly, people choose alpha in this game here, is it the fact that they can’t communicate? Suppose you’d be able to talk beforehand. So suppose the woman here whose name was Mary had been able to talk to the person next to her whose name is Erica, and they’d said, you know, suppose we know we’re going to be paired together, I’ll choose beta if you choose beta. Would that work? Why wouldn’t that work? Yeah? There’s no enforcement. There’s no enforcement, all right? So it isn’t a failure of communication per se, right? A contract is more than communication. A contract is communication with T, right? It actually changes the payoffs. So I could communicate with Ali some agreements, but back home, I’m going to go ahead and choose Alpha anyway. All the better if he’s choosing Peter. All right, so we’ll come back and talk about more of these things as the course goes on, but let’s just come back to the two we forgot there. So the collusion case and the case back in law and order with the prisoners in the cell. How do they enforce their contracts? I mean, they don’t always rat each other out, and some firms manage to collude.

[译文 32]

我想是前面某个人，对吧？所以让我们想想这个。是沟通这里的问题吗？人们在这种场合表现不好，或者在这种游戏中选择alpha的原因，是不是因为他们无法沟通？假设你们能够事先交谈。那么假设这里的这位女士叫Mary，她能够和她旁边的人交谈，她叫Erica，她们说，你知道，假设我们知道我们会被配对在一起，如果你选beta我就选beta。那会有用吗？为什么那不会有作用？是的？没有强制执行。没有强制执行，对吧？所以这不是沟通本身的问题，对吧？合同不仅仅是沟通。合同是附带T的沟通，对吧？它实际上改变了收益。所以我可能和Ali交流一些协议，但回家后我还是会选Alpha。如果他选Peter那就更好了。好的，我们会在课程中回来讨论更多这些事情，但让我们回到我们忘记的两个案例。串通案例以及法律与秩序中囚犯在牢房里的案例。他们如何执行他们的合同？我的意思是，他们并不总是互相告发，而且有些公司确实能够进行串通。

[段 33]

How do they manage to enforce those contracts, those agreements? How are they enforced? They trust each other? It could be they trust each other, although if you trust a crook, that’s not, you know, what elseIf you trust a crook, that’s not, you know, what else could it be? The guy here again with the beard, yeah? It might not be a zero-sum game. Well, but this is the game, right? So here’s the game. No, but the way they value, the way of valuing each decision. The payoff may be different. The payoff may be different. I have something simpler in mind. Suppose they have a written contract or even an unwritten contract. What enforces the contract for colluding firms or crooks in jail? Yeah? Yeah, so a short version of that is it’s a different kind of contract. If you rat someone out in jail, someone puts a contract out on you. Tony Soprano enforces those contracts. That’s the purpose of Tony Soprano. It’s the purpose of the mafia. The reason the mafia thrives in countries where it’s hard to write legal contracts, let’s say some new parts of the former Soviet Union or some parts of Africa, the reason the mafia thrives in those environments is that it substitutes for the law and enforces both legal and illegal contracts. Alright, so I promised a while ago now that we were going to come back and look at this game under some other possible payoffs.

[译文 33]

他们如何执行那些合同，那些协议？它们是如何被执行的？他们互相信任？可能是他们互相信任，虽然如果你信任一个骗子，那你知道，还能是什么这个人又说了，留胡子的那个，对吧？可能不是零和游戏。但这就是游戏，对吧？所以这是游戏。不，但是他们评估的方式，评估每个决定的方式。收益可能不同。收益可能不同。我有一个更简单的想法。假设他们有一份书面合同，甚至一份口头合同。是什么让串通公司或监狱里的骗子执行合同？是的？是的，所以简短的版本是这是一种不同类型的合同。如果你在监狱里告发某人，有人会对你发出一份合同。Tony Soprano执行那些合同。那是Tony Soprano的目的。那是黑手党的目的。黑手党在难以书写法律合同的国家蓬勃发展的原因，比如前苏联的一些新地区或非洲的一些地区，黑手党在这些环境中蓬勃发展是因为它取代了法律，执行着合法和非法的合同。好的，所以我之前承诺过我们要回来看看这个游戏在其他一些可能的收益下的情况。

[段 34]

So, let’s, no, I wasn’t under a contract, but let’s come back and fulfill that promise anyway. So we’re going to revisit, if not the divinity school, at least some people who have more morality than my friends up in the business school. we’re going to ask GodWe’re going to ask for the same grade game we played at the beginning, what would happen if players’ payoffs looked different? So these are possible payoffs too. All right? And I’ll give you the name. We called the other guys Evil Gets, so we’ll call these guys Indignant Angels. I can never spell indignant. Is that roughly right? Does that look right? I think it’s right. Indignant, isn’t it? Indignant. All right, indignant angels, and we’ll see why in a second. So here are their payoffs. And once again, the basic structure of the game hasn’t changed. It’s still, I’m choosing alpha and beta, my pair is choosing alpha and beta, and the grades are the same as they were before. They’re hidden by that board, but you saw them before. All right? But this time, the payoff is as follows. On the lead diagonal, we still have 0, 0, and 1, 1, but now the grades here are minus 1 and minus 3, and here they’re minus 3 and minus 1. And what’s the idea here? These aren’t the only other possible payoffs, it’s just an idea.

[译文 34]

那么，不，我没有被合同约束，但我们还是回来履行那个承诺吧。所以我们要重新审视，如果不是神学院，至少是一些比我在商学院的朋友们更有道德的人。我们要问上帝——我们要问相同的等级游戏我们一开始就玩过的，如果玩家的收益看起来不同会怎样？这些也是可能的收益。对吧？我会给你们名字。我们把另一组人叫做邪恶的混蛋，所以我们把这些家伙叫做愤慨的天使。我总是拼不对愤慨。是这样拼吗？看起来对吗？我认为是。愤慨，不是吗？愤慨。好的，愤慨的天使，我们一会儿会知道为什么。这些是他们的收益。再说一遍，游戏的基本结构没有改变。它仍然是，我在选择alpha和beta，我的搭档在选择alpha和beta，成绩和之前一样。它们被那块板挡住了，但你们之前看到过。对吧？但这一次，收益如下。在主对角线上，我们仍然是0,0和1,1，但现在这里的成绩是负1和负3，而这里它们是负3和负1。想法是什么？这些不是唯一其他可能的收益，只是一个想法。

[段 35]

Suppose I get an A and my pair gets a C, then, sure, I get that initial payoff of 3, but unfortunately, I can’t sleep at night because I’m feeling so guilty. Right? I have some,can’t sleep at night because I’m feeling so guilty. I have some kind of moral conscience and after I’ve subtracted off my guilt feelings, I end up at minus one. So think of this as guilt. Some notion of morality. Alright? Conversely, if I shows a beta and my pair shows an alpha, so I end up with a C and she ends up with an A, then I have a bad time explaining to my parents why I got a C in this class and I have to say about how I’m going to be president anyway, but then in addition I feel indignation against this person. It isn’t just that I got a C. I got a C because she made me get a C. So that moral indignation takes us down to minus 3. So again, I’m not claiming these are the only other possible payoffs, but just another possibility to look at. So suppose these were the payoffs in the game. Again, suspend disbelief a second and imagine that these actually are your payoffs. and let me ask you what you would have done in this case. So think about it a second.

[译文 35]

假设我得到A而我的搭档得到C，那么，当然，我得到那个初始收益3，但不幸的是，我整晚睡不着，因为我感到非常内疚。对吧？我有某种——整晚睡不着，因为我感到非常内疚。我有某种道德良知，在我减去我的内疚感之后，我最终得到负1。所以把这个看作是内疚。某种道德观念。好吧？相反，如果我展示beta而我的搭档展示alpha，所以我最终得到C而她最终得到A，那么我很难向我的父母解释为什么我在这门课得到C，我不得不说我要怎么成为总统什么的，但此外我对这个人感到愤慨。不仅仅是我得到了C。我得到C是因为她让我得到C。所以那种道德愤慨把我们带到负3。所以再说一遍，我不是说这些是唯一其他可能的收益，只是另一种可能性可以看看。假设这些是游戏中的收益。再一次，暂停怀疑一会儿，假设这些确实是你的收益，让我问你你会怎么做。所以想一想。

[段 36]

Now write it down. Write down what you’re going to do on the corner of your notepad. Just write down alpha or beta, what you’re going to do here. You’re not all writing. The guy in the England shirt isn’t writing. You’ve got to be writing during an England shirt. Show it to your neighbor. Let’s have a show of hands. Again, I want you to keep your hands up so that Jude can see it now. So how many of you chose alpha in this case? Raise your hands. Come on over here. Raise your hands. How many shows beta in this case?shy, raise your hands. How many chose beta in this case? How many people abstained? Not allowed to abstain. Let’s try it again. Alpha, alpha in this case, no extensions here. Beta in this case? So we’re roughly splitting the room. Someone who chose alpha, can you raise the alphas again? Let me get this guy here. Alec, can we get this guy here? So why did you choose alpha? You would minimize your losses. You’d get zero or negative one instead of negative 3 or 1. All right. So this gentleman’s saying… It’s a dominant strategy, so… Right. So this gentleman’s saying a good reason for choosing alpha in this game is it’s less risky, right? The worst-case scenario is less bad. All right. What about somebody who shows beta?

[译文 36]

现在写下来。把你要做什么写在你笔记本的角落上。就写下alpha或beta，你在这里要做什么。你们没有都在写。那个穿英格兰衬衫的家伙没在写。穿英格兰衬衫的时候你得写。给你旁边的看看。让我们举手。再来一次，我希望你们把手举起来，这样Jude现在能看到。那么你们中有多少人在这种情况下选了alpha？举手。过来这边。举手。在这种情况下有多少人选了beta？——嗯，害羞，举手。在这种情况下有多少人选了beta？有多少人弃权？不允许弃权。让我们再试一次。Alpha，在这种情况下选alpha，这里没有延期。在这种情况下选beta？所以我们大约对半开。那个选了alpha的人，你能再举起手选alpha的那些人吗？让我看看这个家伙。Alec，我们能看看这个人吗？那你为什么选alpha？你会最小化你的损失。你会得到0或负1而不是负3或1。好的。所以这位先生说……这是一个占优策略，所以……是的。所以这位先生说选alpha的一个好理由是它风险更小，对吧？最坏的情况不那么糟糕。好的。那选beta的人呢？

[段 37]

A lot of you chose beta. Let’s have a show of hands on the betas again. Let me see the betas again. So raise your hands, raise your hands. Can we get the woman here? Can we ask her why she chose beta? Because if you choose alpha, the best case scenario is you get 0. Good, okay, so that’s a good counter-argument. So the gentleman here was looking at the worst case scenario, and the woman here was looking at the best case scenario, and the best case scenario here looks like getting a 1 here. Now, let’s ask a different question. Is one of the strategies dominated in this game? No, neither strategy is dominated. Let’s just check. If my pair chooses alpha, then my choosing alpha yields 0, beta minus 3, so alpha would be better. but if my pair chooses beta then alpha yields minus 1chooses beta then alpha yields minus one, beta yields one, in this case beta would be better. So alpha in this case is better against alpha and beta is better against beta but neither dominates each other. So here’s a game where we just change the payoff, we have the same basic structure, the same outcomes, but we imagine people cared about different things and we end up with a very different answer. In the first game it was kind of clear that we should choose alpha and here it’s not at all clear what we can do, what we should do.

[译文 37]

你们很多人选择了beta。让我们再次举手看看选择beta的人。让我再看看选择beta的人。举手，举手。我们能请那位女士过来吗？能不能问问她为什么选择beta？因为如果你选择alpha，最好的情况是你得到0。好，好的，这是一个很好的反驳。所以这位先生看的是最坏的情况，而这位女士看的是最好的情况，而这里最好的情况看起来是得到1。那么，让我们问一个不同的问题。在这个游戏中，是否有一个策略是被支配的？不，两个策略都不是被支配的。让我们检查一下。如果我的搭档选择alpha，那么我选择alpha得到0，beta得到负3，所以alpha会更好。但如果我的搭档选择beta，那么alpha得到负1，beta得到1，这种情况下beta会更好。所以alpha在这种情况下对alpha更好，而beta对beta更好，但彼此谁都不支配谁。这是一个游戏，我们只是改变了收益，我们有相同的基本结构，相同的结果，但我们假设人们在乎不同的东西，最终得到了一个非常不同的答案。在第一个游戏中，我们选择alpha是相当清楚的，而在这里，我们能做什么、应该做什么一点也不清楚。

[段 38]

In fact this kind of game has a name and we’ll revisit it later on in the semester. This kind of game is called a coordination problem. And we’ll talk about coordination problems later on. But the main lesson I want to get out of this for today is a simple lesson. It’s the lesson that payoffs matter. We change the payoffs. We change what people cared about, and we get a very different game with a very different outcome. All right? So the basic lesson is that payoffs matter, but let me say it a different way. So without giving away my age too much, well, I guess it will, actually, when I was a kid growing up in England, there was this guy, there was a pop star, a slightly post-punk pop star called Joe Jackson, who none of you will have heard of because you’re all about 10 years old. Not my fault. and Joe Jackson had this song which had the lyric, something like, you can’t get what you want unless you know what you want. You can’t get what you want unless you know what you want. And as a statement of logic, that’s false. It could be that what you want just drops into your lap without you knowing about it. But as a statement of strategy, it’s a pretty good idea. It’s a good idea to try and figure out what your goals are, what you’re trying to achieve, before you go ahead and analyze the game.

[译文 38]

事实上，这种游戏有一个名字，我们在这个学期的后面会再讲到它。这种游戏叫做协调问题。我们后面会讲到协调问题。但我今天想从中得出的主要教训是一个简单的教训。那就是收益很重要。我们改变收益，我们改变人们在乎的东西，就会得到一个非常不同的游戏和非常不同的结果。明白吗？所以基本教训是收益很重要，但让我换一种方式说。在我不太暴露年龄的情况下，好吧，我想它会的，当我是个在英格兰长大的孩子时，有这么一个人，一个流行歌星，一个稍微后朋克时代的流行歌星叫Joe Jackson，你们谁都没听说过，因为你们都大约10岁。不是我的错。Joe Jackson有首歌，里面有句歌词，大意是，除非你知道你想要什么，否则你无法得到你想要的。除非你知道你想要什么，否则你无法得到你想要的。作为一个逻辑陈述，那是错误的。你想要的东西可能会莫名其妙地落到你手里。但作为一个战略陈述，这是一个相当好的想法。在你继续分析游戏之前，试着弄清楚你的目标是什么，你想达成什么，这是一个好主意。

[段 39]

So, payoffs matter. Let’s put it in his version. You can’t get what you want until you know what you want. Be honest, how many of you have heard of Joe Jackson? Oh, it makes me feel old. Oh, man. Okay. It goes down every year. All right. So, so far, we’ve looked at this game as played by people who are evil gits, and we’ve looked at this game as played by people who are indignant angels. But we can do something more interesting. We can imagine playing this game on a sort of mix and match. For example, imagine, this shouldn’t be hard for most of you, imagine that you are an evil get, but you know that the person you’re playing against is an indignant angel. I say again, imagine that you know you’re an evil gate, but you know that the person you’re playing against or with is an indignant angel. What should you do in that case? What should you do in that case? Who thinks you should choose alpha in that case? Let’s have pan the room again. We can. Keep your hands up so you can see. Who thinks you should choose beta in that case? who’s abstaining here I’m not going to abstain in this class it’s a complete no-no so we’ll allow some abstentions on the first day but not beyond the day let’s have a look let’s analyse this combined game so what does this game look like it’s an evil git versus an indignant angel and we can put the payoff matrix together by combining the matrices we had before.

[译文 39]

所以，收益很重要。让我们用他的版本来说。除非你知道你想要什么，否则你无法得到你想要的。老实说，你们有多少人听说过Joe Jackson？哦，这让我觉得自己老了。哦，伙计。每一年都在下降。好。所以到目前为止，我们看过这个游戏被邪恶混蛋们玩过，我们也看过这个游戏被愤愤不平的天使们玩过。但我们可以做更有趣的事情。我们可以想象以某种混合搭配的方式玩这个游戏。例如，想象一下，这对你们大多数人来说应该不难，想象你是一个邪恶混蛋，但你知道你正在对抗的人是愤愤不平的天使。我再说一遍，想象你知道你是一个邪恶混蛋，但你知道你正在与之对抗或合作的人是愤愤不平的天使。在这种情况下你应该怎么做？这种情况下你应该怎么做？谁认为在这种情况下你应该选择alpha？让我们再次环顾房间。我们可以。让你们的手保持举着，这样你能看到。谁认为在这种情况下你应该选择beta？谁弃权了？我在这个课上不会弃权，这是完全不允许的，所以我们会在第一天允许一些弃权，但第一天之后就不允许了。让我们来看看，让我们分析这个组合游戏。那么这个游戏是什么样的呢？这是一个邪恶混蛋对一个愤愤不平的天使，我们可以通过组合我们之前有的矩阵来放在一起。

[段 40]

So in this case, this is me, as always. This is my pair, the column player. My payoffs are going to be what? My payoffs are going to be the evil git payoffs. So they come from the matrix up there. So if someone can help me with reading it off there, That’s a 0, a 3, a minus 1, and a 1. All right? My…1. My opponent or my partner’s payoffs come from the indignant angel matrix. So they come from here. There is 0, a minus 3, a minus 1, and a 1. Everyone see how I constructed that? So I’ll just remind you again, the first payoff is the row player’s payoff, in this case the evil gate, and the second payoff is the column player’s payoff, in this case the indignant angel. Alright, well now we’ve set it up as a matrix, let’s try again that question I asked before. Suppose you’re the role player here, you’re the evil git, those are your payoffs, you’re playing against an indignant angel, what would you do? Right? So, once again, no abstentions this time. Who would choose alpha? Let’s have a show of hands again. Keep your hands up a second. And who would choose beta? Very few betas, mostly alphas. Alpha, I think, is the right answer here, but why? Why? Why is alpha the right answer here?

[译文 40]

所以在这种情况下，这是我一直以来的我。这是我的搭档，列玩家。我的收益将是什么？我的收益将是邪恶混蛋的收益。所以它们来自上面的矩阵。如果有人能帮我读出来，那是0、3、负1和1。好的？我的……1。我的对手或我的搭档的收益来自愤愤不平的天使矩阵。所以它们来自这里。有0、负3、负1和1。大家明白我是怎么构造的吗？那我再来提醒你们一次，第一个收益是行玩家的收益，在这种情况下是邪恶混蛋，第二个收益是列玩家的收益，在这种情况下是愤愤不平的天使。好，既然我们已经把它设置成一个矩阵了，让我们再试试我之前问的那个问题。假设你是行玩家，你是邪恶混蛋，那是你的收益，你在对抗一个愤愤不平的天使，你会怎么做？对？那么，再来一次，这次不允许弃权。谁会选择alpha？让我们再次举手。让你们的手保持举一会儿。谁会选择beta？很少有人选择beta，大部分是alpha。Alpha，我想这里是正确答案，但为什么？为什么？为什么alpha是正确答案？

[段 41]

So, yeah, can we get this guy here? Yeah. It’s the dominant strategy. Good, good. Actually, nothing has changed from the game we started with. The fact I changed the other guy’s payoffs didn’t matter here. Alpha was dominant before. It dominated beta before, and it still dominates beta. Let’s just check. If my opponent chooses alpha, and I choose alpha, I get zero. Beta, I get minus one, so alpha would be better. If my opponent chooses beta and I choose alpha, I get 3. Beta, I get 1. Once again, alpha is better. So as before, alpha does betteralpha is better. So as before, alpha does better than beta for me, regardless of what the other person does, alpha dominates beta. What was the first lesson of the class? What was the first lesson of the class? Shouting out, please. Right, right. So you should all have been choosing in this game. You all should have chosen alpha, right? So the one person who didn’t will let him off for today. Okay? Okay? So alpha dominates beta here. All right, let’s flip things around. All right, suppose now, harder to imagine, but let’s try it. Suppose now that you are an indignant angel, and you’re playing against, and you know this, you’re playing against an evil gate. You’re an indignant angel, so you have the payoffs that are still there, and you’re playing against the evil gate, which is the payoffs we covered up, but we’ll reproduce them.

[译文 41]

那么，能请这位先生过来吗？是的。这是占优策略。好的，好的。实际上，这与我们开始时的游戏没有任何变化。我改变另一个人的收益这件事在这里并不重要。Alpha之前是占优的。它之前支配beta，它现在仍然支配beta。让我们检查一下。如果我的对手选择alpha，而我选择alpha，我得到0。选beta，我得到负1，所以alpha会更好。如果我的对手选择beta，而我选择alpha，我得到3。选beta，我得到1。再次，alpha更好。所以和之前一样，alpha对我而言无论另一个人做什么都比beta表现更好，alpha支配beta。什么是这节课的第一个教训？什么是这节课的第一个教训？请大声喊出来。对，对。所以你们都应该在这个游戏中做出选择。你们都应该选择alpha，对吧？所以那个没有选择的人，我今天放过他。好吗？好吗？所以alpha在这里支配beta。好，让我们把情况反过来。好，假设现在，更难想象，但我们试试看。假设现在你是一个愤愤不平的天使，而你知道，你在对抗一个邪恶混蛋。你是一个愤愤不平的天使，所以你有仍然在那里的收益，而你在对抗邪恶混蛋，那就是我们盖住的收益，但我们会再现它们。

[段 42]

Let’s produce that matrix. By the way, this is beginning to sound like a wrestling match. I don’t mean it to. Let’s try here. Alpha, beta, alpha, beta, pair, me. So my payoffs this time are the indignant angel pay off. So mine are 0, minus 1, minus 3, and 1. And my opponent’sand 1, and my opponent’s payoffs are, what would have been my payoffs before? They come from the other matrix, as I show you it. They come from this matrix, so they’re going to be 0, minus 1, 3, 1. 0, minus 1, 3, 1. I took the second payoff from that matrix and made it the second payoff in this matrix. Okay, everyone see how I did that? Once again, the row player is the first payoff and the column player is the other payoff. All right, what should you do in this case? You’re the indignant angel. You’re playing against this evil gate. What should you do? Write down on your notepad what you should do. Show it to your neighbor so you can’t cheat. Well, you can cheat, but you’ll be shamed in front of your neighbor. And raise your hand. We’ll let Jude see it. Raise your hand and keep them up. if you chose alpha now? And how about if you chose beta now? So one or two betas, mostly alphas. Well, let’s see, let’s reason this through a second.

[译文 42]

让我们产生那个矩阵。顺便说一下，这开始听起来像一场摔跤比赛。我不是故意的。让我们在这里试试。Alpha，beta，alpha，beta，搭档，我。所以我的收益这次是愤愤不平的天使的收益。所以我的是0、负1、负3和1。而我对手的收益是，我之前会有的收益是什么？它们来自另一个矩阵，就像我给你们看的。它们来自这个矩阵，所以它们将是0、负1、3和1。0、负1、3和1。我取了那个矩阵的第二个收益并把它变成这个矩阵的第二个收益。好的，大家明白我是怎么做的了吗？再次，行玩家是第一个收益，列玩家是另一个收益。好，在这种情况下你应该怎么做？你是愤愤不平的天使。你在对抗这个邪恶混蛋。你应该怎么做？在你的笔记本上写下你应该怎么做。把它展示给你的邻居，这样你就不能作弊了。嗯，你可以作弊，但你会当着邻居的面丢脸。然后举手。我们会让Jude看到它。举手并保持举着。如果你现在选择了alpha？以及如果你现在选择了beta呢？所以一两个beta，大部分是alpha。那么，让我们看看，让我们推理一下。

[段 43]

Does alpha, does my alpha dominate my beta? No, in fact, alpha doesn’t dominate beta for me. It doesn’t dominate beta. If my pair chooses alpha, then alpha gets me 0 beta minus 3, so alpha does better. But if my pair chooses beta, then alpha gets me minus 1, beta gets to be 1, in this case beta is better. So once again, as we saw before, alpha is better against alpha, beta is better against beta, there’s no dominance going on here. Nevertheless, at least 90% of you chose alpha here. And that’s the right answer. Why? Why should you choose alpha here? Somebody, can we get the guy with the beard here? Yeah, wait for the mic. There you go, great. We’ve acknowledged that alpha is a dominant strategy for my opponent, so we must choose based upon knowing that my opponent’s going to choose alpha. Good, good. And your name is? Henry. So Henry’s saying, sure, I don’t have a dominated strategy. My alpha doesn’t dominate my beta. But look at my opponent. My opponent’s alpha dominates her beta. If I choose alpha, and she chooses alpha, she gets zero. Beta, she gets minus one. Alpha is better. If I choose beta, if she chooses alpha, she gets three. Beta, one. Again, alpha is better. For my opponent, alpha dominates beta. So by thinking about my opponent, by putting myself in my opponent’s shoes, I realize that she has a dominant strategy, alpha.

[译文 43]

alpha是否，我的alpha是否支配我的beta？不，事实上，alpha对我没有支配beta。它不支配beta。如果我的搭档选择alpha，那么alpha让我得到0，beta得到-3，所以alpha更好。但如果我的搭档选择beta，那么alpha让我得到-1，beta得到1，这种情况下beta更好。所以又一次，正如我们之前看到的，alpha对抗alpha时更好，beta对抗beta时更好，这里没有支配关系。然而，你们中至少90%在这里选择了alpha。而这是正确答案。为什么？为什么你应该在这里选择alpha？有人，我们能叫那个留胡子的家伙过来吗？好，等一下麦克风。你来了，很好。我们已经承认alpha对我的对手来说是优势策略，所以我们必须基于知道我的对手会选择alpha来做选择。好，好。你叫什么名字？Henry。所以Henry说，当然，我没有被支配的策略。我的alpha不支配我的beta。但看看我的对手。我的对手的alpha支配她的beta。如果我选择alpha，她选择alpha，她得到0。Beta，她得到-1。Alpha更好。如果我选择beta，她选择alpha，她得到3。Beta，1。还是alpha更好。对我的对手来说，alpha支配beta。所以通过考虑我的对手，通过设身处地为我的对手着想，我意识到她有一个优势策略，alpha。

[段 44]

She’s going to choose alpha. And my best response against alpha is to choose alpha myself. So here, this time, my alpha does not dominate beta andbeta, but my pair’s choice of alpha dominates her choice, her possible choice of beta. So she will choose alpha, and once I know that she’s going to choose alpha, it’s clear that I should choose alpha and get 0 rather than beta and get minus 3. So I should choose alpha also. All right. Okay, so now we’ve seen four different combinations. We’ve seen a case where an evil gate was playing an evil gate, where an indignant angel was playing an indignant angel, and we’ve seen both the flips of those, the evil gate versus the indignant angel, and the indignant angel against the evil gate. Why are we doing this? Because there’s an important lesson here. What’s the lesson here? The lesson is, comes from this game, that a great way to analyze game, a great way to get used to the idea of strategic thinking, perhaps even the essence of strategic thinking, is the ability to put yourself in someone else’s shoes, figure out what their payoffs are, and try and figure out what they’re going to do. All right? So the big lesson of this game is, I forgot what number we’re up to, I guess it’s lesson four, I think.

[译文 44]

她会选择alpha。我针对alpha的最佳应对就是自己也选择alpha。所以在这里，这次，我的alpha并不支配beta和beta，但我对alpha的选择支配了她的选择，她可能的beta选择。所以她会选择alpha，一旦我知道她要选择alpha，显然我应该选择alpha得到0分而不是beta得到-3分。所以我也应该选择alpha。好的，所以我们已经看到了四种不同的组合。我们已经看到了一种情况，即邪恶之门对抗邪恶之门，愤怒的天使对抗愤怒的天使，我们也看到了这两种情况的翻转，即邪恶之门对阵愤怒的天使，以及愤怒的天使对阵邪恶之门。为什么我们要这样做？因为这其中有一个重要的教训。教训是什么？教训是，来自这个游戏，分析游戏的好方法，熟悉战略思维概念的好方法，甚至可能是战略思维的本质，就是能够设身处地地理解他人，搞清楚他们的收益是什么，并尝试弄清楚他们要做什么。好的？所以这个游戏的重要教训是，我忘了我们进行到第几课了，我想应该是lesson four，我想。

[段 45]

Lesson four is, Thank you.put yourself in others shoes and try to figure out what they will do and in a sense this is the first difficult lesson of the class. It’s easy to spot when a strategy is dominant, more or less. It’s pretty easy to figure out you have to know about your own payoffs, but the hard thing in life is getting you to come out of your own selves a bit, realizing it’s, quote, not all about you. You’ve got to put yourself in other people’s shoes to figure out what they care about and what they’re going to try and do so you can respond well to that. And while we’re here, let’s just mention that things get more complicated in a world where I don’t actually know the payoffs of my opponent. It’s much easier to figure out my own payoffs than to figure out my opponent’s payoffs. I might not know whether I’m playing someone who’s an evil git or an indignant angel, so I’m going to have to figure out what the odds are of that in doing this exercise. And we’re going to come back to that idea too way at the end of the class. We’re getting a bit ahead of ourselves, but we’ll get there. Now it turns out that this game, this Prisoner’s Dilemma with the alphas and betas, or essentially the same game, has been played many, many, many timesbetas are essentially the same game, has been played many, many, many times in experiments.

[译文 45]

第四课是，谢谢。把自己放在别人的立场上，试着弄清楚他们会做什么，从某种意义上说，这是本课第一个困难的课程。发现一个策略是否占优势或多或少是容易的。弄清楚你必须了解自己的收益是相当容易的，但生活中困难的事情是让你从自我中走出来一点，意识到引用一下，“这不全是你自己的事”。你必须把自己放在别人的立场上，弄清楚他们关心什么，他们打算做什么，这样你才能很好地回应。当我们在这里时，让我们提一下，在我实际上不知道对手收益的世界里，事情会变得更复杂。弄清楚我自己的收益比弄清楚对手的收益要容易得多。我可能不知道我是在和一个evil git还是一个indignant angel玩游戏，所以我必须在这个练习中弄清楚这种情况的概率。我们还会在课程结束时再次讨论这个想法。我们有点超前了，但我们会达到的。现在事实证明，这个游戏，这个带有alphas和betas的囚徒困境，或者基本相同的游戏，在实验中已经进行了很多很多很多次。

[段 46]

So out there in the real world, we can do this here, out there in the real world, when they do these experiments, they find out that roughly 70% of people choose alpha, and roughly 30% choose beta. Roughly, almost a third choose beta. Now what do we think is going on? That’s a third of the people who seem to be choosing a dominated strategy, or is it? What’s going on there? Why do you think 30% of people are choosing beta? Anybody? Can we catch this guy here? They might be motivated by the fact that every person who chooses beta raises the average score. Right, they could be moral people. They could be more so one possibility is this 30% of people in the real world who choose beta. I just dice people All right, what else could it be? Yeah, I know this might be changing the game a little bit But if you ever expected to play the same game with the partner all right So they have more they could be thinking they’re gonna play again long run payoffs are greater if you choose beta every time So they could be that they think this is actually they haven’t understood the experiment and they think this is a multi-shot game not a one-shot game. Good. What else could it be? What’s the simplest explanationgood.

[译文 46]

所以在现实世界中，我们在这里可以做这个，在现实世界中，当他们做这些实验时，他们发现大约70%的人选择alpha，大约30%的人选择beta。大约，几乎三分之一的人选择beta。那么我们认为发生了什么？那是三分之一的人似乎在选择一个被支配的策略，是这样吗？那里发生了什么？你为什么认为30%的人选择beta？有谁？能抓住这个人吗？他们可能是因为这样的动机：每个选择beta的人都会提高平均分。对，他们可能是道德高尚的人。还有一种可能性是现实世界中这30%选择beta的人。我只是掷骰子的人。好的，还有什么其他的？是的，我知道这可能会稍微改变游戏，但如果你期望与同一个搭档玩这个游戏，好的，他们可能认为他们会再次玩，长期收益如果每次都选择beta会更大。所以他们可能是这样想的：他们实际上没有理解这个实验，他们认为这是一个多轮游戏而不是一轮游戏。好的。还有什么？最简单的解释是什么？好的。

[段 47]

What else could it be? What’s the simplest explanation? What’s the other obvious explanation? They could just be stupid, right? It could be, right? We’re allowed to say that in class, right? Let’s be honest here. When we say experiments in the real world in game theory, or the ones you read about in the New York Times, the real world when it comes to experiments in economics really means undergraduates at the University of Arizona. I’m not making it up. It just does, they all are. And I don’t know anything about it. Any of you from Arizona? I don’t know. I don’t know whether the average undergraduate at the University of Arizona just has a sunny personality or whether they’ve spent too long in the sun. I just don’t know which it is, right? We can’t really distinguish from this. How about in Yale? What’s our numbers here? How about in this class? Do you want to mic your colleague here? Yeah. 2.38 versus 36. So 238 at Yale, this is Yale, versus 36. So even at my level of arithmetic, that’s a lot less than 30%. That’s more like less than 15%. No, it’s about 15%, I guess. All right? So 238 shows alpha, and 36 shows beta. Now, there’s one more lesson in this class, and this is going to be it. This isn’t the end of the class, but one more lesson to take home.

[译文 47]

还能是什么？最简单的解释是什么？另一个明显的解释是什么？他们可能就是蠢，对吧？可能就是这样，对吧？我们在课堂上可以这么说，对吧？咱们实话实说。当我们说博弈论中的真实世界实验，或者你在《纽约时报》上读到的那些实验，经济学的真实世界实验其实指的就是亚利桑那大学的大学生。我没瞎编。就是这样，都是这样。我对此一无所知。你们中有来自亚利桑那的吗？我不知道。我不知道亚利桑那大学的一般大学生是天生性格开朗，还是在太阳下待太久了。我就是不知道是哪种情况，对吧？我们实际上无法从这里区分出来。在耶鲁怎么样？我们这里的数据是多少？这节课上怎么样？你们谁有麦克风借给同事用一下？好。2.38比36。所以238是Yale，这是Yale，而36是Arizona。所以即便以我的算术水平，这也远不到30%。这更像是不到15%。不，大概是15%左右，对吧？那么238表示alpha，36表示beta。现在，这节课还有最后一课，这就来了。这不是课堂的结束，而是还有一课要带回家。

[段 48]

You guys are going to be playing games among each other, today and until whatever it is, December 7th, whatever it is, the end of the end of term. Alright? So look around you.is the end of term. All right? Look around each other. You better get to know each other a bit. All right? And what have we learned today about you guys? The lesson here, lesson five, is Yale students are evil. All right? Be aware of that when you’re playing games. All right. I want to play one more game today in the remaining minutes. It doesn’t matter if we finish a little bit earlier, but I want to try and get this game at least started. So do you all have game number two in front of you? Just reading that over, can I also make sure you’ve all got your legal forms and you’re going to sign? Don’t walk away with your legal forms. You need to get those collected in. So at the end of talking about this game, I’m going to collect in both the second game for the class and also the legal form. If you don’t have a legal form, if you’ve lost it or something, it’s online. Alright? It’s online. All right, let’s have a look at that second game. I’ll read it out for you. Game two, pick a number.

[译文 48]

你们之后要互相玩游戏，从今天开始一直到December 7号左右，或者学期结束的时候。好吗？所以看看你周围。学期结束了。好吗？互相认识一下。你们最好多了解一下彼此。好吗？那么今天我们从你们身上学到了什么？这里的教训，也就是lesson five，就是Yale students are evil。好吗？在玩游戏的时候要意识到这一点。好吗？我想在剩下的时间里再玩一个游戏。提前一点结束也没关系，但我至少要尝试把这个游戏开始。所以你们面前都有game number two了吗？先看一下这个，我还要确认你们都有legal forms并且准备签字。不要把legal forms带走。你们需要把它们收上来。所以在这款游戏讲解结束时，我会同时收集第二个游戏和legal form。如果你没有legal form，如果你弄丢了或者怎样，它在网上。好吗？它在网上。好的，让我们看看第二个游戏。我来给你们读一下。Game two, pick a number。

[段 49]

Everyone got this? Anyone not got this? Without showing your neighbor what you’re doing, put in the box below a whole number between 1 and 100. Whole number between 1 and 100, integer. We will calculate the average number chosen in the class. the winner in this game is the person whose number is closest to 230.whose number is closest to two-thirds times the average in the class. Again, the winner is the person whose number is closest to two-thirds times the average number in the class. And the winner will win $5 minus the difference in pennies between her choice and that two-thirds of the average. Now, just to make sure you’ve understood this, let me do an example on the board. I’ve got one more board, that’s good. So imagine there were three people in the class, and imagine that they chose 25, 5, and 60. All right, so 25 plus 5 plus 60 is 90. People feel free to correct my arithmetic, because it’s often wrong. 90, right? And 90, two-thirds of 90, so two thirds of 90 two thirds of whoops, what do I need? Start again. I need to divide it by 3 to get the average so the average is 30. Thank you. Somebody? So the total is 90. The average is 30. Am I right so far? So two thirds of the average two thirds of the average is 20.

[译文 49]

大家都明白了吗？有人还不明白吗？不要让你旁边的人看到你在做什么，在下面的框里输入一个1到100之间的整数。1到100之间的整数。我们会计算全班选出的数字的平均值。这个游戏的获胜者是数字最接近全班平均数三分之二的人。再说一遍，获胜者是数字最接近全班平均数三分之二的人。获胜者将赢得5美元减去她的选择与平均数三分之二之间的差额（以分为单位）。现在，为确保你们理解这一点，让我在黑板上举个例子。我还有一块白板，挺好的。假设班里有三个人，他们选了25、5和60。好的，那么25加5加60是90。大家可以随时纠正我的算术，因为我经常算错。90，对吧？90，三分之二是90的三分之二，90的三分之二，呃，我需要什么？重新开始。我需要除以3得到平均值，所以平均值是30。谢谢。有人吗？总和是90。平均值是30。到这里对吗？平均数的三分之二，平均数的三分之二是20。

[段 50]

I’m looking desperately at the TA. Is that right? Okay. Alright, so the averageIs that right? Okay. All right. So the average is 30 and two-thirds of the average is 20. All right. So who’s the winner here? Which number would have won here? 25 would have won. 25 would have been the closest. And what would they have won? They’d have won five bucks minus five cents for a total of $4.95. All right. Now to make this interesting, let’s play this for real. so this of course relies on me having brought some money and being able to do this without dislodging the microphone alright so I’m going to see if I have sorry about that, I’m going to see if I have enough money to do this class for real, when we played this game in the old days during the dot com boom with the MBA students, you had to put 50 bucks on the table to get them interested graduate students, 5 cents will do it ok so this is a there’s some bloke with a beard on this one yeah this is, okay this is Lincoln apparently Lincoln apparently, who knew, Lincoln okay alright so this is a five dollar note and I’m going to put it sorry about that again, I’m going to put it in an envelope, I’m not cheating anybody right no magic tricks here and this is going to be the prize for this game and we better give this to someone we trust alright so prize for 159.

[译文 50]

我急切地看着助教。这样对吗？好的。平均数是30，平均数的三分之二是20。好的。那么谁在这里赢了？哪个数字会赢？25会赢。25最接近。赢家会得到什么？他们会赢得五美元减去五美分，总共4.95美元。好的。现在为了让这更有趣，让我们真实地玩这个游戏。这当然取决于我是否带了钱，能否在不碰到麦克风的情况下完成这件事，所以我要看看我是否有足够的钱为这个班真实地做这件事。当我们在网络泡沫时代和MBA学生玩这个游戏时，你必须在桌上放50美元才能让他们感兴趣。研究生，5美分就够了。所以这是一个，这个上面有一个胡子的人，是的，这是，好的，这是林肯，显然，林肯，显然，谁知道呢，林肯，好的，所以这是一张五美元钞票，我要把它放进信封，抱歉又这样了，我不会骗任何人，没有魔术把戏，这将是这个游戏的奖品，我们最好把它给一个我们信任的人，所以奖品是给159的。

[段 51]

Who do you guys trust? The camera guy. Okay, Jude. We know Jude’s going to be there next week. I’m giving it to Jude. You can’t see this on camera, people at home, but I’m giving it to Jude, okay? I’m going to put it here. And Jude has to therefore show up next week with the prize, okay? All right? I thought we should give it to the guy at the back who is the moral guy. Who is our moral guy at the back? Never mind. We’ll give it to Jude. We know Jude’s going to be here. All right. Has everyone put a number down? Any questions? Yes. Yes, just shout them out to me. So given that we only have one $5 bill, does there have to be one unique winner? And if so, how is that determined if we have multiple people who are positive? Well, well, well, that’s a good question. If there’s multiple winners, we’ll divide it, but we’ll make sure everyone has a positive winning, okay? Good question. Good. Given the number of people in the room, there may be multiple winners. I accept that, accept that possibility. Has everyone written down a number now? All right. So hand your numbers to the end of the row, but don’t go yet. Hand your numbers to the end of the row. Before you go, I want five things from you.

[译文 51]

你们信任谁？摄像师。好的，朱德。我们知道朱德下周会在场。我把它给你。家里的人看不到，但我把它给朱德，好吗？我要把它放在这里。因此朱德必须下周带着奖品出现，好吗？好的。我以为我们应该把它给后面那个有道德的人。我们后面谁是有道德的人？没关系。我们把它给朱德。我们知道朱德会在这里。每个人都写下数字了吗？有问题吗？是的。有问题就喊出来。既然我们只有一张5美元的钞票，是否必须有唯一的赢家？如果有多个赢家，如何决定？我们有多个正数的人？嗯，嗯，嗯，这是个好问题。如果有多个赢家，我们会分，但我们会确保每个人都有正的赢家，好吗？好问题。我接受，考虑到房间里的人数，可能有多个赢家。我接受这种可能性。现在每个人都写下数字了吗？好的，把你的数字传到这一排的尽头，但先别走。在你走之前，我想要你们提供五样东西。

[段 52]

I want to know the five lessons from this class. Tell me what you learned. What were the five lessons? Without looking at your notes, what were the five lessons? Anybody? Shout out one of the lessons. Yes, madam. Don’t play a strictly dominated strategy. Anything else? Anything else? Yes, sir. Yale students are evil. Yale students are evil. Two lessons down, three to go. The guy over here. Rational choice can lead to bad outcomes. We put it more graphically before, but that’s fine. See?outcomes. We put it more graphically before but that’s fine. Two more outcomes. Put yourself in other people’s shoes and I’m missing one. I can’t remember what I’m missing now. You can’t get what you want. You could but it’s a good idea to figure out what you want before you try and get what you want. Five things you learned today. Hand in your numbers and the legal forms and I’ll see you on Monday.

[译文 52]

我想知道这节课的五个教训。告诉我你学到了什么。五个教训是什么？不看笔记，五个教训是什么？有人？喊出一个教训。是的，女士。不要玩严格被支配的策略。还有其他的吗？还有其他的吗？是的，先生。耶鲁的学生是邪恶的。耶鲁的学生是邪恶的。两个教训完成，三个待完成。这边的家伙。理性选择可能导致不良结果。我们之前更形象地表达了这一点，但这样也可以。还有两个。还有两个。把你自己放在别人的立场上，但我还缺一个。我现在记不起我缺什么了。你不能得到你想要的。你可以，但它是一个好主意，在尝试得到你想要的之前，先弄清楚你想要什么。今天学到的五件事。交出你的数字和法律表格，周一见。