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  • We all make decisions every day; we want to know

    我們每天都作出決定;我們想知道如何做

  • what the right thing is to do -- in domains from the financial

    正確的事情——從金融

  • to the gastronomic to the professional to the romantic.

    到烹飪到職業到愛情。

  • And surely, if somebody could really tell us how to do

    當然,如果有人能夠真的能告訴我們

  • exactly the right thing at all possible times,

    在所有可能的時刻如何做正確的事情,

  • that would be a tremendous gift.

    那可是一份非凡的智慧。

  • It turns out that, in fact, the world was given this gift in 1738

    事實上,早在1738年,荷蘭博學家Daniel Bernoulli

  • by a Dutch polymath named Daniel Bernoulli.

    就為世人提供了這項智慧。

  • And what I want to talk to you about today is what that gift is,

    我今天想講的是這項智慧是什麽,

  • and I also want to explain to you why it is

    以及,我想向各位解釋

  • that it hasn't made a damn bit of difference.

    爲什麽這項智慧根本就沒有影響我們的生活。

  • Now, this is Bernoulli's gift. This is a direct quote.

    這就是Bernoulli提供的智慧。這是他的原文。

  • And if it looks like Greek to you, it's because, well, it's Greek.

    如果這看上去像希臘文,因為,它就是希臘文。

  • But the simple English translation -- much less precise,

    把它簡單翻譯成英文——雖然不夠精確,

  • but it captures the gist of what Bernoulli had to say -- was this:

    但它抓住了Bernoulli所表達的要點:

  • The expected value of any of our actions --

    我們所有行為的預期值——

  • that is, the goodness that we can count on getting --

    即是,我們所能期望得到的好處——

  • is the product of two simple things:

    是以下兩個簡單事物的乘積:

  • the odds that this action will allow us to gain something,

    這就是,該行為能使我們獲益的機率,

  • and the value of that gain to us.

    和我們從中所獲得的益處的價值。

  • In a sense, what Bernoulli was saying is,

    在某種意義上而言,Bernoulli所說的是,

  • if we can estimate and multiply these two things,

    如果我們能夠評估這兩者並把它們相乘,

  • we will always know precisely how we should behave.

    我們就會精確的知道自己應該怎麼做。

  • Now, this simple equation, even for those of you

    那麼,這個簡單的公式,即使對那些

  • who don't like equations, is something that you're quite used to.

    不喜歡公式的人而言,也是很平常簡單的。

  • Here's an example: if I were to tell you, let's play

    舉個例子:如果我告訴你,讓我們來玩

  • a little coin toss game, and I'm going to flip a coin,

    一個拋硬幣的遊戲,我會拋一個硬幣,

  • and if it comes up heads, I'm going to pay you 10 dollars,

    如果是正面朝上,我會給你10元,

  • but you have to pay four dollars for the privilege of playing with me,

    但你得花4元來得到這個與我玩的機會,

  • most of you would say, sure, I'll take that bet. Because you know

    你們大多數人會說,好,我參加。因為你們知道

  • that the odds of you winning are one half, the gain if you do is 10 dollars,

    你們贏的機會是一半,如果贏的話會得到10元,

  • that multiplies to five, and that's more

    兩者相乘得5,這比我收取的

  • than I'm charging you to play. So, the answer is, yes.

    費用要多。所以,你會回答,好。

  • This is what statisticians technically call a damn fine bet.

    這就是統計師們技術上所稱的很棒的賭局。

  • Now, the idea is simple when we're applying it to coin tosses,

    那麼,當我們把這個原理應用到拋硬幣上時,是很簡單的,

  • but in fact, it's not very simple in everyday life.

    但實際上,在應用到日常生活中卻並不那麼簡單。

  • People are horrible at estimating both of these things,

    人們評估兩者的能力非常糟糕,

  • and that's what I want to talk to you about today.

    而這就是我今天想要談論的話題。

  • There are two kinds of errors people make when trying to decide

    人們在為自己的行為作決策時,

  • what the right thing is to do, and those are

    會犯兩種錯誤,

  • errors in estimating the odds that they're going to succeed,

    即錯誤地估計成功的機率,

  • and errors in estimating the value of their own success.

    以及錯誤地估計成功的價值。

  • Now, let me talk about the first one first.

    首先讓我談談第一個錯誤。

  • Calculating odds would seem to be something rather easy:

    計算機率看起來是件很簡單的事情:

  • there are six sides to a die, two sides to a coin, 52 cards in a deck.

    一個骰子有六面,一個硬幣有兩面,一副撲克牌有52張。

  • You all know what the likelihood is of pulling the ace of spades

    你們都知道摸到黑桃A或者

  • or of flipping a heads.

    拋出硬幣正面的可能性。

  • But as it turns out, this is not a very easy idea to apply

    但結果是,這個道理如果應用於日常生活的時候,

  • in everyday life. That's why Americans spend more --

    就不那麼容易了。這也是爲什麽美國人花了更多的錢——

  • I should say, lose more -- gambling

    我應該說,輸了更多的錢——在賭博上。

  • than on all other forms of entertainment combined.

    這些錢比所有其他娛樂形式費用的總和還要多。

  • The reason is, this isn't how people do odds.

    原因就是,人們並不用這種方式來計算機率。

  • The way people figure odds

    要談論人們計算機率的方式,

  • requires that we first talk a bit about pigs.

    我們先得談談和豬有關的事宜。

  • Now, the question I'm going to put to you is whether you think

    我現在要問你們的問題是,

  • there are more dogs or pigs on leashes

    在牛津的任何一天,

  • observed in any particular day in Oxford.

    你認為被拴的狗多還是被拴的豬多。

  • And of course, you all know that the answer is dogs.

    當然,你們都知道答案是狗。

  • And the way that you know that the answer is dogs is

    你知道這個答案是狗

  • you quickly reviewed in memory the times

    是靠你快速地回憶

  • you've seen dogs and pigs on leashes.

    看到狗和豬被拴的次數。

  • It was very easy to remember seeing dogs,

    我們很容易記起見到被拴的狗,

  • not so easy to remember pigs. And each one of you assumed

    但不那麼容易記起被拴的豬。而且你們每個人會假設

  • that if dogs on leashes came more quickly to your mind,

    如果狗被拴的情景更快地出現在你的腦海中的話,

  • then dogs on leashes are more probable.

    那麼狗被拴的可能性更大。

  • That's not a bad rule of thumb, except when it is.

    這個憑感覺的方法還不錯,但也有例外。

  • So, for example, here's a word puzzle.

    舉例說,這裡有個填詞遊戲。

  • Are there more four-letter English words

    在四個字母的英文單詞裡,第三個字母是R的單詞

  • with R in the third place or R in the first place?

    與第一個字母是R的單詞哪個比較多?

  • Well, you check memory very briefly, make a quick scan,

    嗯,你們會很快搜索下記憶,作一個快速掃描,

  • and it's awfully easy to say to yourself, Ring, Rang, Rung,

    對你來說記起這些單詞太容易了,Ring,Rang,Rung,

  • and very hard to say to yourself, Pare, Park: they come more slowly.

    而記起Pare,Park就很難:它們在腦海中出現得更慢。

  • But in fact, there are many more words in the English language

    而實際上,在英文裡,第三字母是R的單詞,

  • with R in the third than the first place.

    比第一字母是R的單詞要多得多。

  • The reason words with R in the third place come slowly to your mind

    你回憶起第三字母是R的單詞比較慢的原因,

  • isn't because they're improbable, unlikely or infrequent.

    不是因為它們不存在,不大可能出現或使用頻率少。

  • It's because the mind recalls words by their first letter.

    而是因為我們的大腦是用第一個字母來回憶單詞。

  • You kind of shout out the sound, S -- and the word comes.

    我們好像是用大腦在讀這個單詞的音,S——然後單詞就出來了。

  • It's like the dictionary;

    很像詞典;

  • it's hard to look things up by the third letter.

    我們很難用第三個字母來查找單詞。

  • So, this is an example of how this idea that

    所以,這個例子說明一個道理,

  • the quickness with which things come to mind

    即我們大腦回憶事物的速度,

  • can give you a sense of their probability --

    會影響你對該事物出現的可能性的感覺——

  • how this idea could lead you astray. It's not just puzzles, though.

    而這個道理可能會讓你出現誤差。這並不僅限於填詞遊戲。

  • For example, when Americans are asked to estimate the odds

    譬如說,當讓美國人估計他們

  • that they will die in a variety of interesting ways --

    奇奇怪怪的死因的機率時——

  • these are estimates of number of deaths per year

    這些估計數據是以每年每兩億美國人

  • per 200 million U.S. citizens.

    的死亡人數而計。

  • And these are just ordinary people like yourselves who are asked

    他們只是一些是跟你我一樣的普通人。問他們

  • to guess how many people die from tornado, fireworks, asthma, drowning, etc.

    猜測一下會有多少人死於颶風,煙花,哮喘,溺水等等。

  • Compare these to the actual numbers.

    讓我們跟實際數據比較一下。

  • Now, you see a very interesting pattern here, which is first of all,

    你們可以看到一個非常有趣的現象,首先,

  • two things are vastly over-estimated, namely tornadoes and fireworks.

    兩者被大幅高估,即颶風和煙花;

  • Two things are vastly underestimated:

    兩者被大幅低估:

  • dying by drowning and dying by asthma. Why?

    溺水和哮喘。爲什麽?

  • When was the last time that you picked up a newspaper

    你們還記得上次拿起一張報紙,

  • and the headline was, "Boy dies of Asthma?"

    上面的的大標題是“男孩死於哮喘”是什麽時候嗎?

  • It's not interesting because it's so common.

    這沒什麽稀奇因為太普通了。

  • It's very easy for all of us to bring to mind instances

    對我們來說,非常容易記起

  • of news stories or newsreels where we've seen

    我們曾看到報紙和電視上的新聞報導

  • tornadoes devastating cities, or some poor schmuck

    諸如颶風摧毀城市,或是某個可憐的笨蛋

  • who's blown his hands off with a firework on the Fourth of July.

    在國慶節被煙花炸掉雙手。

  • Drownings and asthma deaths don't get much coverage.

    對因溺水和哮喘而死的報導並不多。

  • They don't come quickly to mind, and as a result,

    我們並不會很快記起這類事件,而結果就是,

  • we vastly underestimate them.

    我們極度低估了它們。

  • Indeed, this is kind of like the Sesame Street game

    的確,這就有點像芝麻街遊戲

  • of "Which thing doesn't belong?" And you're right to say

    "哪樣東西與眾不同?" 你說游泳池不同

  • it's the swimming pool that doesn't belong, because the swimming pool

    就對了,因為游泳池是

  • is the only thing on this slide that's actually very dangerous.

    這張上唯一非常危險的東西。

  • The way that more of you are likely to die than the combination

    也就是說,你們死於游泳池的可能性

  • of all three of the others that you see on the slide.

    比這張圖片上其他三種加起來還要高。

  • The lottery is an excellent example, of course -- an excellent test-case

    彩票是一個很棒的例子,一個測試

  • of people's ability to compute probabilities.

    人們計算可能性的能力的例子。

  • And economists -- forgive me, for those of you who play the lottery --

    先對那些買彩票的朋友說聲抱歉,

  • but economists, at least among themselves, refer to the lottery

    但經濟學家們,至少在他們之間,把彩票稱為

  • as a stupidity tax, because the odds of getting any payoff

    愚蠢之稅,因為投資買彩票

  • by investing your money in a lottery ticket

    而中獎的可能性

  • are approximately equivalent to flushing the money

    跟把錢直接沖進馬桶差不多

  • directly down the toilet -- which, by the way,

    而且,沖馬桶還

  • doesn't require that you actually go to the store and buy anything.

    不需要你親自去彩票店跑一趟。

  • Why in the world would anybody ever play the lottery?

    究竟世上爲什麽會有人想買彩票呢?

  • Well, there are many answers, but one answer surely is,

    嗯,有許多答案,但其中肯定包括這個答案:

  • we see a lot of winners. Right? When this couple wins the lottery,

    我們看到許多中大獎的人。對吧?當這對夫妻贏了大獎,

  • or Ed McMahon shows up at your door with this giant check --

    或Ed McMahon帶著一張巨大的支票來到你家門口時——

  • how the hell do you cash things that size, I don't know.

    我可不知道你怎麼用那麼巨大的支票去換錢。

  • We see this on TV; we read about it in the paper.

    我們在電視上看到這些,在報紙上讀到這些。

  • When was the last time that you saw extensive interviews

    你們什麽時候見過對每個輸錢的人

  • with everybody who lost?

    所作出的大量採訪呢?

  • Indeed, if we required that television stations run

    的確,如果我們要求電視台

  • a 30-second interview with each loser

    每次採訪大獎得主的時候,

  • every time they interview a winner, the 100 million losers

    必須播放對每個輸家一段30秒的採訪,

  • in the last lottery would require nine-and-a-half years

    那麼上次開獎後你得全神貫注地花上9年半的時間

  • of your undivided attention just to watch them say,

    來看那1億輸家採訪,你會看到他們說,

  • "Me? I lost." "Me? I lost."

    "我?我輸了。" "我?我輸了。"

  • Now, if you watch nine-and-a-half years of television --

    那麼,如果你看了九年半的電視——

  • no sleep, no potty breaks -- and you saw loss after loss after loss,

    不睡不拉——你就會往復循環地看到輸輸輸,

  • and then at the end there's 30 seconds of, "and I won,"

    然後最後的30秒"我贏了",

  • the likelihood that you would play the lottery is very small.

    這樣你去買彩票的可能性就很小了。

  • Look, I can prove this to you: here's a little lottery.

    來,我可以證明給你:這兒有個小彩票。

  • There's 10 tickets in this lottery.

    一共有10張彩票。

  • Nine of them have been sold to these individuals.

    其中9張已經賣給其他不同的人了,

  • It costs you a dollar to buy the ticket and, if you win,

    1元1張票,如果你贏了,

  • you get 20 bucks. Is this a good bet?

    你得到20元。值得賭嗎?

  • Well, Bernoulli tells us it is.

    嗯,Bernoulli告訴我們肯定的答案:

  • The expected value of this lottery is two dollars;

    這個彩票的預期價值是2元,

  • this is a lottery in which you should invest your money.

    你應該投資購買該彩票。

  • And most people say, "OK, I'll play."

    大多數人會說,"好,我會買。"

  • Now, a slightly different version of this lottery:

    現在,稍微改變一下彩票規則:

  • imagine that the nine tickets are all owned

    假設9張票全部

  • by one fat guy named Leroy.

    給一個叫Leroy的胖子買走了。

  • Leroy has nine tickets; there's one left.

    Leroy有9張票;那就只剩下1張。

  • Do you want it? Most people won't play this lottery.

    你還會買嗎?大多數人不想買了。

  • Now, you can see the odds of winning haven't changed,

    你可以看到贏的機率並沒有改變,

  • but it's now fantastically easy to imagine who's going to win.

    但現在非常容易想像出誰會是贏家。

  • It's easy to see Leroy getting the check, right?

    很容易看出Leroy會贏獎,對吧?

  • You can't say to yourself, "I'm as likely to win as anybody,"

    你不會對自己說,"我跟其他人得獎的機會一樣大。"

  • because you're not as likely to win as Leroy.

    因為你跟Leroy得獎的機會不一樣大。

  • The fact that all those tickets are owned by one guy

    所有其他彩票被一個人買走的事實

  • changes your decision to play,

    改變了你是否要買的決定,

  • even though it does nothing whatsoever to the odds.

    儘管你知道你贏的機率一點都沒變。

  • Now, estimating odds, as difficult as it may seem, is a piece of cake

    那麼,評估可能性的難度,雖然看起來很難,

  • compared to trying to estimate value:

    但與評估價值相比較,簡直是小菜一碟:

  • trying to say what something is worth, how much we'll enjoy it,

    評估價值就是試圖找出某樣東西的價值,我們對它的享受程度,

  • how much pleasure it will give us.

    它會帶給我們多少快樂。

  • I want to talk now about errors in value.

    我現在想談下價值的錯誤。

  • How much is this Big Mac worth? Is it worth 25 dollars?

    這個巨無霸漢堡包值多少錢?值25元嗎?

  • Most of you have the intuition that it's not --

    大多數人直覺它不值——

  • you wouldn't pay that for it.

    你不會花那麼多錢買它。

  • But in fact, to decide whether a Big Mac is worth 25 dollars requires

    而實際上,決定一個巨無霸漢堡是否值25元,

  • that you ask one, and only one question, which is:

    只需要你問一個問題而已,即:

  • What else can I do with 25 dollars?

    我還能用25元做什麽?

  • If you've ever gotten on one of those long-haul flights to Australia

    如果你曾坐過那種去澳大利亞的長途航班,

  • and realized that they're not going to serve you any food,

    而且得知他們不會提供任何食物,

  • but somebody in the row in front of you has just opened

    但你前排有個人剛剛打開了

  • the McDonald's bag, and the smell of golden arches

    麥當勞的紙袋,那金黃色圓麵包的香味

  • is wafting over the seat, you think,

    從座位上方飄了過來,這時你會想,

  • I can't do anything else with this 25 dollars for 16 hours.

    我在這16個小時用這25元什麽也不能做。

  • I can't even set it on fire -- they took my cigarette lighter!

    我甚至不能點燃它——他們把我的打火機收走了!

  • Suddenly, 25 dollars for a Big Mac might be a good deal.

    突然,25元買個巨無霸漢堡可能是筆好交易。

  • On the other hand, if you're visiting an underdeveloped country,

    相反的情況,如果你去參觀一個發展中國家,

  • and 25 dollars buys you a gourmet meal, it's exorbitant for a Big Mac.

    25元就可以讓你大快朵頤,而買巨無霸漢堡就太貴了。

  • Why were you all sure that the answer to the question was no,

    爲什麽在我還沒告訴你們所處的情境時,

  • before I'd even told you anything about the context?

    你們都確定對這個問題的答案是"不"呢?

  • Because most of you compared the price of this Big Mac

    因為你們大多數人將這個巨無霸漢堡的價格

  • to the price you're used to paying. Rather than asking,

    與你們過去常付的價格比較。而不是問,

  • "What else can I do with my money," comparing this investment

    "我還能用這錢幹什麼",即將這項投資與

  • to other possible investments, you compared to the past.

    其他可能的投資比較,你們是與過去的情境比較。

  • And this is a systematic error people make.

    而這是人們犯的一個系統性錯誤。

  • What you knew is, you paid three dollars in the past; 25 is outrageous.

    你所知道的是,你在過去是花3元;如果花25元就太過分了。

  • This is an error, and I can prove it to you by showing

    這是一個錯誤,我可以證明給大家看,

  • the kinds of irrationalities to which it leads.

    我會展示給大家看它可以導致什麼樣的非理性。

  • For example, this is, of course,

    舉例來說,

  • one of the most delicious tricks in marketing,

    一個最有效的營銷技巧是,

  • is to say something used to be higher,

    告訴顧客商品的原價更高,

  • and suddenly it seems like a very good deal.

    這樣的話,現價一下子就看起來很划算了。

  • When people are asked about these two different jobs:

    當人們被問及兩份工作時:

  • a job where you make 60K, then 50K, then 40K,

    第一份工作你的年薪先是6萬元,然後5萬元,然後4萬元,

  • a job where you're getting a salary cut each year,

    每年都會減薪,

  • and one in which you're getting a salary increase,

    第二份工作是每年都會加薪,

  • people like the second job better than the first, despite the fact

    人們更喜歡第二份工作,儘管事實上

  • they're all told they make much less money. Why?

    他們都被告知會賺得更少。爲什麽會這樣?

  • Because they had the sense that declining wages are worse

    因為他們感覺逐年遞減的工資比

  • than rising wages, even when the total amount of wages is higher

    遞增的工資要差,儘管總數算起來前者要比

  • in the declining period. Here's another nice example.

    後者多。這裡有另外一個例子。

  • Here's a $2,000 Hawaiian vacation package; it's now on sale for 1,600.

    這是一套價值二千元的夏威夷假日套票,現在促銷價是一千六百元

  • Assuming you wanted to go to Hawaii, would you buy this package?

    假設你想去夏威夷,你願意買這個套票嗎?

  • Most people say they would. Here's a slightly different story:

    大多數人會同意購買。那麼把條件稍微改變一下:

  • $2,000 Hawaiian vacation package is now on sale for 700 dollars,

    2000元的夏威夷假日套票現在只售700元,

  • so you decide to mull it over for a week.

    於是你考慮了一個星期。

  • By the time you get to the ticket agency, the best fares are gone --

    等你來到售票代理的時,最好的價格過期了——

  • the package now costs 1,500. Would you buy it? Most people say, no.

    現在的價格是一千五百元。你還會買嗎?大多數人會說,不會。

  • Why? Because it used to cost 700, and there's no way I'm paying 1,500

    爲什麽?因為它過去的價格是七百元,而我絕不會花一千五百元

  • for something that was 700 last week.

    買上個星期只有七百元的東西。

  • This tendency to compare to the past

    人們喜歡與過去的事物比較的傾向

  • is causing people to pass up the better deal. In other words,

    導致人們錯過了更好的交易。換句話說,

  • a good deal that used to be a great deal is not nearly as good

    一個划算的交易,會因為它之前更划算而導致現在顯得不那麼划算,

  • as an awful deal that was once a horrible deal.

    同樣,一個糟糕的交易,會因為之前更糟糕而導致現在顯得不那麼糟糕。

  • Here's another example of how comparing to the past

    這是另外一個跟過去比較是

  • can befuddle our decisions.

    如何迷惑我們的決策的例子。

  • Imagine that you're going to the theater.

    假設你要去劇院。

  • You're on your way to the theater.

    你在去劇院的路上。

  • In your wallet you have a ticket, for which you paid 20 dollars.

    你錢包里放著你花了20元買的一張票。

  • You also have a 20-dollar bill.

    你也有一張20元的鈔票。

  • When you arrive at the theater,

    當你到達劇院時,

  • you discover that somewhere along the way you've lost the ticket.

    你發現不知怎樣電影票在路上丟了。

  • Would you spend your remaining money on replacing it?

    你會花剩下的錢再買一張嗎?

  • Most people answer, no.

    大多數人的答案是,不會。

  • Now, let's just change one thing in this scenario.

    那麼,讓我們把這個情境改變一點。

  • You're on your way to the theater,

    你在去劇院的路上,

  • and in your wallet you have two 20-dollar bills.

    在你的錢包裡有兩張20元的鈔票。

  • When you arrive you discover you've lost one of them.

    當你到達劇院時你發現丟了一張。

  • Would you spend your remaining 20 dollars on a ticket?

    你會花剩下的20元買電影票嗎?

  • Well, of course, I went to the theater to see the play.

    嗯,當然了:我是去劇院看電影的。

  • What does the loss of 20 dollars along the way have to do?

    在路上丟了20元跟這個有什麽關係?

  • Now, just in case you're not getting it,

    萬一你還不太明白,

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