兩個(gè)大腦在運(yùn)轉(zhuǎn)，一個(gè)快一個(gè)慢

Two Brains Running

兩個(gè)大腦在運(yùn)轉(zhuǎn)，一個(gè)快一個(gè)慢

In 2002, Daniel Kahneman won the Nobel in economic science. What made this unusual is that Kahneman is a psychologist. Specifically, he is one-half of a pair of psychologists who, beginning in the early 1970s, set out to dismantle an entity long dear to economic theorists: that arch-rational decision maker known as Homo economicus. The other half of the dismantling duo, Amos Tversky, died in 1996 at the age of 59. Had Tversky lived, he would certainly have shared the Nobel with Kahneman, his longtime collaborator and dear friend.

丹尼爾·卡納曼(Daniel Kahneman)于2002年獲得諾貝爾經(jīng)濟(jì)學(xué)獎(jiǎng)。有意思的是，卡納曼是一位心理學(xué)家。具體說來(lái)，他的貢獻(xiàn)就在于他與另一位心理學(xué)家阿莫斯·特維斯基 (Amos Tversky(自二十世紀(jì)七十年代初開始，挑戰(zhàn)、瓦解了經(jīng)濟(jì)學(xué)理論界長(zhǎng)期抱持的一個(gè)概念：稱作“經(jīng)濟(jì)人”(Homo economicus)的理性優(yōu)先決策者。特維斯基于1996年逝世，享年59歲。如果他還活著，他肯定會(huì)與其長(zhǎng)期的合作者和摯友卡納曼共享諾貝爾獎(jiǎng)。

Human irrationality is Kahneman’s great theme. There are essentially three phases to his career. In the first, he and Tversky did a series of ingenious experiments that revealed twenty or so “cognitive biases” — unconscious errors of reasoning that distort our judgment of the world. Typical of these is the “anchoring effect”: our tendency to be influenced by irrelevant numbers that we happen to be exposed to. (In one experiment, for instance, experienced German judges were inclined to give a shoplifter a longer sentence if they had just rolled a pair of dice loaded to give a high number.) In the second phase, Kahneman and Tversky showed that people making decisions under uncertain conditions do not behave in the way that economic models have traditionally assumed; they do not “maximize utility.” The two then developed an alternative account of decision making, one more faithful to human psychology, which they called “prospect theory.” (It was for this achievement that Kahneman was awarded the Nobel.) In the third phase of his career, mainly after the death of Tversky, Kahneman has delved into “hedonic psychology”: the science of happiness, its nature and its causes. His findings in this area have proved disquieting — and not just because one of the key experiments involved a deliberately prolonged colonoscopy.

“人類的非理性”是卡納曼的主要研究對(duì)象。他的職業(yè)生涯基本上分為三個(gè)階段。在第一階段，他和特維斯基做了一系列別出心裁的實(shí)驗(yàn)，揭示了二十多個(gè) “認(rèn)知偏差”(cognitive biases)——推理中無(wú)意識(shí)的差錯(cuò)歪曲了我們對(duì)世界的判斷。其中具有代表性的是“錨定效應(yīng)”(anchoring effect)：我們傾向于受正巧展露給我們的不相干數(shù)字的影響(例如，在一次實(shí)驗(yàn)中，經(jīng)驗(yàn)豐富的德國(guó)法官如果擲出一對(duì)骰子后，剛好得到一個(gè)大數(shù)字，那么他們對(duì)商店扒手判的刑期就更長(zhǎng))。在第二階段，卡納曼和特維斯基證明，在不確定的情況下做決定的人，并非如傳統(tǒng)經(jīng)濟(jì)學(xué)模型所假定的那樣行事，他們并沒有 “效用最大化”(maximize utility)。兩人隨后發(fā)展出另一種更符合人類心理的解釋決策的理論，他們稱之為“預(yù)期理論”(prospect theory，卡納曼便是因?yàn)檫@一成就獲得諾貝爾獎(jiǎng))。在其職業(yè)生涯的第三個(gè)階段——主要是在特維斯基過世以后——卡納曼轉(zhuǎn)向研究“享樂心理學(xué)” (hedonic psychology)：快樂行為學(xué)及其性質(zhì)和成因。他在這一領(lǐng)域的發(fā)現(xiàn)證明是令人不安的——這不僅僅是因?yàn)槠渲幸粋€(gè)關(guān)鍵實(shí)驗(yàn)涉及一次故意延長(zhǎng)的結(jié)腸鏡檢查。

“Thinking, Fast and Slow” spans all three of these phases. It is an astonishingly rich book: lucid, profound, full of intellectual surprises and self-help value. It is consistently entertaining and frequently touching, especially when Kahneman is recounting his collaboration with Tversky. (“The pleasure we found in working together made us exceptionally patient; it is much easier to strive for perfection when you are never bored.”) So impressive is its vision of flawed human reason that the New York Times columnist David Brooks recently declared that Kahneman and Tversky’s work “will be remembered hundreds of years from now,” and that it is “a crucial pivot point in the way we see ourselves.” They are, Brooks said, “like the Lewis and Clark of the mind.”

《思考，快與慢》(Thinking, Fast and Slow)的內(nèi)容貫穿了以上這三個(gè)階段。這本書內(nèi)容豐富，它清晰、深刻，充滿智慧的驚喜和自助價(jià)值。全書讀來(lái)妙趣橫生，在很多時(shí)候也很感人，尤其是卡納曼講述他和特維斯基共事的時(shí)候(“我們?cè)谝黄鸸ぷ鳙@得的樂趣使我們變得格外地耐心;當(dāng)你樂此不疲時(shí)，就不難做到精益求精。”)它對(duì)人類理性缺陷的洞見令人印象深刻，《紐約時(shí)報(bào)》專欄作家大衛(wèi)·布魯克斯(David Brooks)最近就宣稱，卡納曼和特維斯基的工作“將會(huì)流芳百世”，是“我們?nèi)绾慰创约旱年P(guān)鍵支點(diǎn)”。布魯克斯說，他們“就像思想界的‘路易斯與克拉克遠(yuǎn)征’ ”。

間接宣布了人類的非理性

Now, this worries me a bit. A leitmotif of this book is overconfidence. All of us, and especially experts, are prone to an exaggerated sense of how well we understand the world — so Kahneman reminds us. Surely, he himself is alert to the perils of overconfidence. Despite all the cognitive biases, fallacies and illusions that he and Tversky (along with other researchers) purport to have discovered in the last few decades, he fights shy of the bold claim that humans are fundamentally irrational.

現(xiàn)在，該說說讓我略微不安的部分。這本書的一個(gè)主題是關(guān)于過分自信?？{曼提醒我們，我們所有人，尤其是專家，容易夸張地感覺自己是多么了解這個(gè)世界。當(dāng)然，他自己對(duì)過分自信保持了警惕。盡管他和特維斯基(與其他研究者一道)宣稱在最近幾十年里發(fā)現(xiàn)了種種認(rèn)知偏差、謬論和錯(cuò)覺，他始終不愿勇敢地宣布，人根本就是非理性的。

Or does he? “Most of us are healthy most of the time, and most of our judgments and actions are appropriate most of the time,” Kahneman writes in his introduction. Yet, just a few pages later, he observes that the work he did with Tversky “challenged” the idea, orthodox among social scientists in the 1970s, that “people are generally rational.” The two psychologists discovered “systematic errors in the thinking of normal people”: errors arising not from the corrupting effects of emotion, but built into our evolved cognitive machinery. Although Kahneman draws only modest policy implications (e.g., contracts should be stated in clearer language), others — perhaps overconfidently? — go much further. Brooks, for example, has argued that Kahneman and Tversky’s work illustrates “the limits of social policy”; in particular, the folly of government action to fight joblessness and turn the economy around.

抑或他做了間接的宣布?“我們大部分人在大部分時(shí)候都是健康的，我們大部分判斷和行動(dòng)在大部分時(shí)候都是恰當(dāng)?shù)?rdquo;，卡納曼在序言中寫道。然而，就在幾頁(yè)之后，他又說，他和特維斯基所做的工作“挑戰(zhàn)”了1970年代社會(huì)學(xué)家普遍持有的觀念：“人大致是理性的。”兩位心理學(xué)家發(fā)現(xiàn)“在正常人的思考中存在系統(tǒng)性的差錯(cuò)”：差錯(cuò)的出現(xiàn)不是源于情緒的惡劣影響，而是內(nèi)置于我們逐漸演化的認(rèn)知機(jī)制里。盡管卡納曼僅僅提出一些最為尋常的政策建議(例如，合同應(yīng)該用更清晰的語(yǔ)言表述)，其他人卻發(fā)揮得更多——也許是過于自信?比如，布魯克斯認(rèn)為，卡納曼和特維斯基的工作表明了“社會(huì)政策的局限”，尤其是政府為解決失業(yè)問題、扭轉(zhuǎn)經(jīng)濟(jì)局面所干的蠢事。

Such sweeping conclusions, even if they are not endorsed by the author, make me frown. And frowning — as one learns on Page 152 of this book — activates the skeptic within us: what Kahneman calls “System 2.” Just putting on a frown, experiments show, works to reduce overconfidence; it causes us to be more analytical, more vigilant in our thinking; to question stories that we would otherwise unreflectively accept as true because they are facile and coherent. And that is why I frowningly gave this extraordinarily interesting book the most skeptical reading I could.

這些過于籠統(tǒng)的結(jié)論，尚不論作者未必贊成，至少是令我皺眉的。而皺眉——你會(huì)在本書第152頁(yè)了解到——會(huì)激發(fā)我們的懷疑：懷疑卡納曼所謂的“第二系統(tǒng)”。實(shí)驗(yàn)表明，單是皺眉就可有效減輕過度自信;能讓我們?cè)谒伎贾懈朴诜治觯泳X;能讓我們對(duì)那些因其輕易可得、條理井然而不假思索接受的故事產(chǎn)生疑問。這就是我為什么會(huì)皺著眉頭，持最懷疑的態(tài)度來(lái)閱讀這本非常有趣的書。

System 2, in Kahneman’s scheme, is our slow, deliberate, analytical and consciously effortful mode of reasoning about the world. System 1, by contrast, is our fast, automatic, intuitive and largely unconscious mode. It is System 1 that detects hostility in a voice and effortlessly completes the phrase “bread and. . . . ” It is System 2 that swings into action when we have to fill out a tax form or park a car in a narrow space. (As Kahneman and others have found, there is an easy way to tell how engaged a person’s System 2 is during a task: just look into his or her eyes and note how dilated the pupils are.)

在卡納曼的模式中，第二系統(tǒng)是我們?cè)谒妓魇澜鐣r(shí)緩慢的、有意的、分析的、自覺努力的模式，第一系統(tǒng)與之相反，是我們快速的、自動(dòng)的、直覺的、大半無(wú)意識(shí)的模式。在一個(gè)聲音中聽到敵意，或者毫不費(fèi)勁地完成“面包和……”這個(gè)短語(yǔ)的是第一系統(tǒng)。而諸如不得不填寫納稅申報(bào)單、把車停在一個(gè)很狹小的停車位等行為，則是第二系統(tǒng)在起作用(卡納曼等人發(fā)現(xiàn)，有一個(gè)簡(jiǎn)單方法可以分辨一個(gè)人的第二系統(tǒng)在一項(xiàng)任務(wù)中所發(fā)揮的程度：只要盯著對(duì)方的眼睛，注意瞳孔的放大程度)

More generally, System 1 uses association and metaphor to produce a quick and dirty draft of reality, which System 2 draws on to arrive at explicit beliefs and reasoned choices. System 1 proposes, System 2 disposes. So System 2 would seem to be the boss, right? In principle, yes. But System 2, in addition to being more deliberate and rational, is also lazy. And it tires easily. (The vogue term for this is “ego depletion.”) Too often, instead of slowing things down and analyzing them, System 2 is content to accept the easy but unreliable story about the world that System 1 feeds to it. “Although System 2 believes itself to be where the action is,” Kahneman writes, “the automatic System 1 is the hero of this book.” System 2 is especially quiescent, it seems, when your mood is a happy one.

更寬泛地說，第一系統(tǒng)運(yùn)用聯(lián)想和隱喻快速、粗糙地勾畫出現(xiàn)實(shí)世界的草圖，第二系統(tǒng)進(jìn)而達(dá)到明確的信念和理性的選擇。第一系統(tǒng)提出意圖，第二系統(tǒng)執(zhí)行。所以，第二系統(tǒng)似乎是老板，對(duì)吧?在原則上是的。但第二系統(tǒng)不僅僅更有意圖、更加理性，同時(shí)也是懶惰的。它容易疲倦(流行的術(shù)語(yǔ)是“自我損耗” 【ego depletion】)。與放慢節(jié)奏、對(duì)事物進(jìn)行分析相反，第二系統(tǒng)常常滿足于第一系統(tǒng)提供給它的簡(jiǎn)單卻不可靠的關(guān)于這個(gè)世界的描述。“雖然第二系統(tǒng)相信自己乃行動(dòng)之所在，”卡納曼寫道：“但自動(dòng)的第一系統(tǒng)才是本書的主角。”當(dāng)你心情愉快時(shí)，第二系統(tǒng)似乎尤其不活躍。

At this point, the skeptical reader might wonder how seriously to take all this talk of System 1 and System 2. Are they actually a pair of little agents in our head, each with its distinctive personality? Not really, says Kahneman. Rather, they are “useful fictions” — useful because they help explain the quirks of the human mind.

這時(shí)，持懷疑態(tài)度的讀者也許會(huì)思忖，究竟要多認(rèn)真地看待關(guān)于第一系統(tǒng)和第二系統(tǒng)的說法。它們真是我們頭腦中各自帶有鮮明個(gè)性的一對(duì)小小的代理人嗎?并非如此，卡納曼說道，確切地說，它們是“有用的虛構(gòu)”——有用是因?yàn)樗鼈冇兄诮忉屓祟惖乃季S習(xí)慣。

那個(gè)叫“琳達(dá)”的銀行出納

To see how, consider what Kahneman calls the “best-known and most controversial” of the experiments he and Tversky did together: “the Linda problem.” Participants in the experiment were told about an imaginary young woman named Linda, who is single, outspoken and very bright, and who, as a student, was deeply concerned with issues of discrimination and social justice. The participants were then asked which was more probable: (1) Linda is a bank teller. Or (2) Linda is a bank teller and is active in the feminist movement. The overwhelming response was that (2) was more probable; in other words, that given the background information furnished, “feminist bank teller” was more likely than “bank teller.” This is, of course, a blatant violation of the laws of probability. (Every feminist bank teller is a bank teller; adding a detail can only lower the probability.) Yet even among students in Stanford’s Graduate School of Business, who had extensive training in probability, 85 percent flunked the Linda problem. One student, informed that she had committed an elementary logical blunder, responded, “I thought you just asked for my opinion.”

要明白這一點(diǎn)，請(qǐng)想想“琳達(dá)問題”(the Linda problem)。卡納曼認(rèn)為這是他和特維斯基一起做的“最著名和最具爭(zhēng)議性的”實(shí)驗(yàn)。實(shí)驗(yàn)的參與者會(huì)聽到一個(gè)虛構(gòu)的、名叫琳達(dá)的年輕女人的故事，她單身，坦率，非常開朗，在學(xué)生時(shí)代非常關(guān)注各種歧視和社會(huì)正義。接著，參與者會(huì)接受提問，以下哪一個(gè)更有可能：(1)琳達(dá)是一位銀行出納。(2)琳達(dá)是一位銀行出納，活躍于女權(quán)主義運(yùn)動(dòng)。大多數(shù)人都選擇了(2)。換言之，提供的背景訊息表明“女權(quán)主義的銀行出納員”比“銀行出納員”更有可能。當(dāng)然，這明顯違背了概率法則(每一位女權(quán)主義的銀行出納都是銀行出納;補(bǔ)充的細(xì)節(jié)越多，可能性就越低)。然而，甚至在斯坦福商業(yè)研究院受過大量概率訓(xùn)練的學(xué)生當(dāng)中，也有百分之八十五的人無(wú)法通過琳達(dá)問題。有一位學(xué)生在得知她犯了一個(gè)低級(jí)的邏輯錯(cuò)誤后，答道：“我以為你只是在詢問我的看法。”

What has gone wrong here? An easy question (how coherent is the narrative?) is substituted for a more difficult one (how probable is it?). And this, according to Kahneman, is the source of many of the biases that infect our thinking. System 1 jumps to an intuitive conclusion based on a “heuristic” — an easy but imperfect way of answering hard questions — and System 2 lazily endorses this heuristic answer without bothering to scrutinize whether it is logical.

這是怎么回事?一個(gè)簡(jiǎn)單的問題(敘述有多清晰連貫?)被一個(gè)更難的問題(它有多大可能?)替代了。在卡納曼看來(lái)，這就是我們?cè)谒伎歼^程中出現(xiàn)許多偏差的來(lái)源。第一系統(tǒng)匆匆得出一個(gè)基于“啟發(fā)”的直覺結(jié)論——這是回答艱深問題的一個(gè)簡(jiǎn)單卻不完美的辦法——第二系統(tǒng)就懶惰地接受了這一啟發(fā)式的答案，絲毫不想細(xì)查它是否合乎邏輯。

Kahneman describes dozens of such experimentally demonstrated breakdowns in rationality — “base-rate neglect,” “availability cascade,” “the illusion of validity” and so on. The cumulative effect is to make the reader despair for human reason.

卡納曼描述了許多這類經(jīng)過實(shí)驗(yàn)證明的理性故障——“比率忽略”(base-rate neglect)、“有效性級(jí)聯(lián)”(availability cascade)、“有效性的錯(cuò)覺”(the illusion of validity)等等。其結(jié)果就是逐漸讓讀者對(duì)人類的理性絕望。

Are we really so hopeless? Think again of the Linda problem. Even the great evolutionary biologist Stephen Jay Gould was troubled by it. As an expert in probability he knew the right answer, yet he wrote that “a little homunculus in my head continues to jump up and down, shouting at me — ‘But she can’t just be a bank teller; read the description.’ ” It was Gould’s System 1, Kahneman assures us, that kept shouting the wrong answer at him. But perhaps something more subtle is going on. Our everyday conversation takes place against a rich background of unstated expectations — what linguists call “implicatures.” Such implicatures can seep into psychological experiments. Given the expectations that facilitate our conversation, it may have been quite reasonable for the participants in the experiment to take “Linda is a bank clerk” to imply that she was not in addition a feminist. If so, their answers weren’t really fallacious.

我們真的如此無(wú)可救藥嗎?再想想琳達(dá)問題。甚至連偉大的生物進(jìn)化學(xué)家斯蒂芬·杰伊·古爾德(Stephen Jay Gould)都受到它的困擾。作為一位概率專家，他知道正確的答案，但他寫道，“有一個(gè)小人兒在我頭腦里不斷地跳上跳下，對(duì)我喊道——‘可她不僅僅是一個(gè)銀行出納;看一下描述吧。’”卡納曼使我們相信，是古爾德的第一系統(tǒng)一直朝他喊著錯(cuò)誤的答案。可是，也許發(fā)生著更為微妙的事情。我們的日常對(duì)話都發(fā)生在一個(gè)對(duì)期望未加說明的豐富背景下——語(yǔ)言學(xué)家稱之為“言下之意”(implicatures)。這些言下之意可以滲透到心理實(shí)驗(yàn)中去。鑒于我們都期望讓對(duì)話更加簡(jiǎn)潔，實(shí)驗(yàn)的參與者將“琳達(dá)是一位銀行職”當(dāng)作是在暗示“此外，她并不是一個(gè)女權(quán)主義者”，也是相當(dāng)合理的。如果是這樣，他們的答案就并非那么謬誤。

This might seem a minor point. But it applies to several of the biases that Kahneman and Tversky, along with other investigators, purport to have discovered in formal experiments. In more natural settings — when we are detecting cheaters rather than solving logic puzzles; when we are reasoning about things rather than symbols; when we are assessing raw numbers rather than percentages — people are far less likely to make the same errors. So, at least, much subsequent research suggests. Maybe we are not so irrational after all.

這似乎是一個(gè)次要的問題。但它卻適用于卡納曼和特維斯基，還有其他研究者所聲稱的在正規(guī)的實(shí)驗(yàn)中發(fā)現(xiàn)的一些偏差。在更加自然的情景中——當(dāng)我們?cè)趥刹轵_子而不是解決邏輯謎題，在推斷事物而不是象征物，在評(píng)估原始數(shù)據(jù)而不是百分比的時(shí)候——人們就不太可能出現(xiàn)同樣的差錯(cuò)。至少，后來(lái)的許多實(shí)驗(yàn)都間接地表明了這一點(diǎn)。也許我們根本就不是那么不理性。

Some cognitive biases, of course, are flagrantly exhibited even in the most natural of settings. Take what Kahneman calls the “planning fallacy”: our tendency to overestimate benefits and underestimate costs, and hence foolishly to take on risky projects. In 2002, Americans remodeling their kitchens, for example, expected the job to cost $18,658 on average, but they ended up paying $38,769.

當(dāng)然，一些認(rèn)知偏差甚至公然出現(xiàn)在最為自然的情景中。比如卡納曼所說的“規(guī)劃謬誤”(planning fallacy)：我們傾向于高估利潤(rùn)和低估成本，因而愚蠢地施行一些存在很大風(fēng)險(xiǎn)的方案。例如，在2002年，美國(guó)人改建廚房，預(yù)期這項(xiàng)工作平均花費(fèi) 18,658美元，但他們最后卻花費(fèi)了38,769美元。

The planning fallacy is “only one of the manifestations of a pervasive optimistic bias,” Kahneman writes, which “may well be the most significant of the cognitive biases.” Now, in one sense, a bias toward optimism is obviously bad, since it generates false beliefs — like the belief that we are in control, and not the playthings of luck. But without this “illusion of control,” would we even be able to get out of bed in the morning? Optimists are more psychologically resilient, have stronger immune systems, and live longer on average than their more reality-based counterparts. Moreover, as Kahneman notes, exaggerated optimism serves to protect both individuals and organizations from the paralyzing effects of another bias, “loss aversion”: our tendency to fear losses more than we value gains. It was exaggerated optimism that John Maynard Keynes had in mind when he talked of the “animal spirits” that drive capitalism.

規(guī)劃謬誤“只是一種普遍存在的樂觀偏差的一個(gè)表現(xiàn)”，卡納曼寫道，這“很可能是最重大的認(rèn)知偏差”。在某種意義上，一種傾向于樂觀主義的偏差顯然是糟糕的，因?yàn)樗鼛?lái)錯(cuò)誤的信念——比如：是我們?cè)谡瓶剡\(yùn)氣而不是運(yùn)氣在玩弄我們。但是，如果沒有這一“掌控的錯(cuò)覺”，我們?cè)谠缟仙踔炼紱]辦法起床吧?比起與之相對(duì)應(yīng)的更立足于現(xiàn)實(shí)的人，樂觀主義者更具心理彈性，具備更強(qiáng)大的免疫系統(tǒng)，平均壽命更長(zhǎng)。此外，正如卡納曼所指出的，過分的樂觀主義使個(gè)人和組織都免受另一種偏差的麻痹效應(yīng)，這種偏差就是“損失規(guī)避”(loss aversion)：我們對(duì)損失的畏懼更甚于對(duì)獲利的重視。當(dāng)約翰·梅納爾德·凱恩斯(John Maynard Keynes)談到驅(qū)策資本主義的“動(dòng)物精神”(animal spirits)時(shí)，他頭腦中就存在著過分的樂觀主義。

Even if we could rid ourselves of the biases and illusions identified in this book — and Kahneman, citing his own lack of progress in overcoming them, doubts that we can — it is by no means clear that this would make our lives go better. And that raises a fundamental question: What is the point of rationality? We are, after all, Darwinian survivors. Our everyday reasoning abilities have evolved to cope efficiently with a complex and dynamic environment. They are thus likely to be adaptive in this environment, even if they can be tripped up in the psychologist’s somewhat artificial experiments. Where do the norms of rationality come from, if they are not an idealization of the way humans actually reason in their ordinary lives? As a species, we can no more be pervasively biased in our judgments than we can be pervasively ungrammatical in our use of language — or so critics of research like Kahneman and Tversky’s contend.

即便我們能夠擺脫這本書所指出的那些偏差和錯(cuò)覺——卡納曼以他自己在克服這些偏差和錯(cuò)覺方面殊少進(jìn)步為例，懷疑我們也不能克服它們——我們也根本不清楚這是否能讓我們的生活變得更好。這引發(fā)了一個(gè)根本問題：理性的意義何在?說到底，我們?nèi)际沁_(dá)爾文學(xué)說里的幸存者。我們?nèi)粘５耐评砟芰榱擞行У剡m應(yīng)一個(gè)復(fù)雜的動(dòng)態(tài)環(huán)境，已經(jīng)隨之進(jìn)化了。因此，這些推理能力大概也會(huì)適應(yīng)這一環(huán)境，即便它們?cè)谛睦韺W(xué)家那些多少存在人為因素的實(shí)驗(yàn)中出錯(cuò)。如果理性的模范不是對(duì)人類在日常生活中的實(shí)際推理的一種理想化，那它們又是從何而來(lái)?作為一個(gè)物種，我們不能讓自己的判斷存在普遍的偏差，就像我們不能在使用語(yǔ)言時(shí)普遍地不顧語(yǔ)法——抑或在對(duì)像卡納曼和特維斯基所做的研究進(jìn)行批評(píng)時(shí)也是如此。

幸福是什么?

Kahneman never grapples philosophically with the nature of rationality. He does, however, supply a fascinating account of what might be taken to be its goal: happiness. What does it mean to be happy? When Kahneman first took up this question, in the mid 1990s, most happiness research relied on asking people how satisfied they were with their life on the whole. But such retrospective assessments depend on memory, which is notoriously unreliable. What if, instead, a person’s actual experience of pleasure or pain could be sampled from moment to moment, and then summed up over time? Kahneman calls this “experienced” well-being, as opposed to the “remembered” well-being that researchers had relied upon. And he found that these two measures of happiness diverge in surprising ways. What makes the “experiencing self” happy is not the same as what makes the “remembering self” happy. In particular, the remembering self does not care about duration — how long a pleasant or unpleasant experience lasts. Rather, it retrospectively rates an experience by the peak level of pain or pleasure in the course of the experience, and by the way the experience ends.

卡納曼從未從哲學(xué)上抓住理性的特征。然而，他為能夠作為其目標(biāo)的幸福提供了一個(gè)迷人的描述。幸福是什么意思?當(dāng)卡納曼在1990年代中期首次提出這個(gè)問題時(shí)，大部分對(duì)幸福的研究還依賴于詢問人們?cè)诖篌w上對(duì)他們的生活感到多么滿意。但這種回顧性的評(píng)估依賴于記憶，眾所周知，記憶是不可靠的。如果與此相反，一個(gè)人對(duì)快樂或者痛苦的實(shí)際體驗(yàn)?zāi)軌螂S時(shí)隨地取樣，然后隨著時(shí)間推移加以總結(jié)，那會(huì)怎樣?卡納曼將之稱為“體驗(yàn)的”幸福，與研究者依賴的“記憶的”幸福相對(duì)立。他發(fā)現(xiàn)這兩種對(duì)幸福的衡量方式存在驚人的差異。使“體驗(yàn)的自我”(experiencing self)感到幸福的東西并不是使“記憶的自我”(remembering self)感到幸福的東西。尤其是，記憶的自我并不在乎持續(xù)時(shí)間——不在乎一段愉快或者不愉快的經(jīng)歷持續(xù)多久。它會(huì)通過體驗(yàn)過程中痛苦或者快樂的峰值水平，通過體驗(yàn)的結(jié)果來(lái)回顧性地衡量一段體驗(yàn)。

These two quirks of remembered happiness — “duration neglect” and the “peak-end rule” — were strikingly illustrated in one of Kahneman’s more harrowing experiments. Two groups of patients were to undergo painful colonoscopies. The patients in Group A got the normal procedure. So did the patients in Group B, except — without their being told — a few extra minutes of mild discomfort were added after the end of the examination. Which group suffered more? Well, Group B endured all the pain that Group A did, and then some. But since the prolonging of Group B’s colonoscopies meant that the procedure ended less painfully, the patients in this group retrospectively minded it less. (In an earlier research paper though not in this book, Kahneman suggested that the extra discomfort Group B was subjected to in the experiment might be ethically justified if it increased their willingness to come back for a follow-up!)

記憶的幸福的兩個(gè)缺陷——“對(duì)持續(xù)時(shí)間的忽略”(duration neglect)和“峰終定律”(peak-end rule)——在卡納曼的一個(gè)更令人難受的實(shí)驗(yàn)中得到了驚人的展現(xiàn)。兩組病人要接受痛苦的結(jié)腸鏡檢查。A組病人依照的是正常的程序。B組病人也一樣，只不過——他們沒被告知——在檢查結(jié)束后，額外加上了幾分鐘的輕度不適。哪一組更痛苦呢?嗯，B組承受了A組的全部痛苦，然后還有額外的一些痛苦。但由于B組的結(jié)腸鏡檢查延長(zhǎng)意味著結(jié)束時(shí)的痛苦要小于A組，這一組病人在回顧的時(shí)候就不那么在意(在更早的一篇研究論文中——雖然不在這本書里——卡納曼提出，在這個(gè)實(shí)驗(yàn)中，如果B組受到的這陣額外的不適能夠增強(qiáng)他們回來(lái)參加后續(xù)實(shí)驗(yàn)的意愿，它就是合乎倫理的!)。

As with colonoscopies, so too with life. It is the remembering self that calls the shots, not the experiencing self. Kahneman cites research showing, for example, that a college student’s decision whether or not to repeat a spring-break vacation is determined by the peak-end rule applied to the previous vacation, not by how fun (or miserable) it actually was moment by moment. The remembering self exercises a sort of “tyranny” over the voiceless experiencing self. “Odd as it may seem,” Kahneman writes, “I am my remembering self, and the experiencing self, who does my living, is like a stranger to me.”

在結(jié)腸鏡檢查中是如此，在生活中也是如此。在發(fā)號(hào)施令的是記憶的自我，而不是體驗(yàn)的自我。例如，卡納曼引述研究表明，一個(gè)大學(xué)生決定是否重復(fù)一次春季假期，取決于前一個(gè)假期的峰終定律(peak-end rule)，而不是取決于那一個(gè)一個(gè)瞬間多么有趣(或者多么悲慘)。記憶的自我對(duì)無(wú)聲的體驗(yàn)的自我施加了一種“暴虐”。“好像很奇怪，”卡納曼寫道，“我是我記憶的自我，而那個(gè)過著我的生活的體驗(yàn)的自我，對(duì)我而言就像一個(gè)陌生人。”

Kahneman’s conclusion, radical as it sounds, may not go far enough. There may be no experiencing self at all. Brain-scanning experiments by Rafael Malach and his colleagues at the Weizmann Institute in Israel, for instance, have shown that when subjects are absorbed in an experience, like watching the “The Good, the Bad, and the Ugly,” the parts of the brain associated with self-consciousness are not merely quiet, they’re actually shut down (“inhibited”) by the rest of the brain. The self seems simply to disappear. Then who exactly is enjoying the film? And why should such egoless pleasures enter into the decision calculus of the remembering self?

卡納曼的結(jié)論聽起來(lái)很激進(jìn)，也許還不夠激進(jìn)。也許根本就沒有體驗(yàn)的自我。例如，以色列魏慈曼研究所(Weizmann Institute)的拉斐爾·馬拉克(Rafael Malach)和同事進(jìn)行的大腦掃描實(shí)驗(yàn)表明，當(dāng)實(shí)驗(yàn)對(duì)象專注于一項(xiàng)體驗(yàn)，比如觀看電影《黃金三鏢客》(The Good, the Bad, and the Ugly)，大腦中跟自我意識(shí)聯(lián)系起來(lái)的部分不僅僅是安靜了，實(shí)際上是被大腦的其他部分關(guān)閉(“抑制”)了。自我似乎消失了。那么，到底是誰(shuí)在享受電影呢?為什么這種無(wú)我的快樂會(huì)進(jìn)入記憶的自我的決策演算中呢?

Clearly, much remains to be done in hedonic psychology. But Kahneman’s conceptual innovations have laid the foundation for many of the empirical findings he reports in this book: that while French mothers spend less time with their children than American mothers, they enjoy it more; that headaches are hedonically harder on the poor; that women who live alone seem to enjoy the same level of well-being as women who live with a mate; and that a household income of about $75,000 in high-cost areas of the country is sufficient to maximize happiness. Policy makers interested in lowering the misery index of society will find much to ponder here.

顯然，在享樂心理學(xué)中還有許多研究要做。但卡納曼的觀念革新已經(jīng)為他在書中講到的許多經(jīng)驗(yàn)成果打下了基礎(chǔ)：較之美國(guó)母親，法國(guó)母親與子女待在一起的時(shí)間更少，但她們卻更享受;窮人更受頭痛的侵襲;獨(dú)居的女人似乎與那些有配偶的女人享受著同等的幸福;在這個(gè)國(guó)家的高生活成本地區(qū)，一個(gè)收入大約 75,000美元的家庭足夠?qū)⑿腋Ｗ畲蠡Ｄ切┯兄居诮档蜕鐣?huì)不幸指數(shù)的政策制定者，將會(huì)在這里發(fā)現(xiàn)許多值得深思的東西。

By the time I got to the end of “Thinking, Fast and Slow,” my skeptical frown had long since given way to a grin of intellectual satisfaction. Appraising the book by the peak-end rule, I overconfidently urge everyone to buy and read it. But for those who are merely interested in Kahneman’s takeaway on the Malcolm Gladwell question it is this: If you’ve had 10,000 hours of training in a predictable, rapid-feedback environment — chess, firefighting, anesthesiology — then blink. In all other cases, think.

在讀到《思考，快與慢》結(jié)尾的時(shí)候，我充滿狐疑的皺眉早已舒展開，臉上掛著智性滿足的微笑。根據(jù)峰終定律來(lái)評(píng)價(jià)這本書，我會(huì)過分自信地催促每個(gè)人都去買來(lái)讀。但對(duì)于那些只關(guān)心卡納曼如何售賣馬爾科姆·格拉德維爾問題的人來(lái)說：如果你已經(jīng)在一個(gè)可預(yù)知的、快速反饋的環(huán)境中接受了10,000小時(shí)的訓(xùn)練 ——國(guó)際象棋、消防、麻醉學(xué)——那么，就不用看了。至于其他人，則好好想想吧。