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Elbe New Writ Eames .Book lReview Novembei 2Z 2011 Two Brains Running In the conflict between intuitive and rational decision-making, which side wins? BY JIM HOLT I N 2002, Daniel Kahneman won the Nobel in economic science. What made this unusual — indeed, unique in the history of the-prize — is that Kahneman is a psychologist. Specifically, he Is one-half of a pair of psychologists who. beginning in the early 19/05, set out to dismantle an entity long dear to economic theorists: that arch-rational deciiion maker known as Homo economic- •us, The other half of the dismantling duo. Antos lVersky, died In 19% at the age of 59. Had Tversky lived, he would certainly have shared the Nobel with Kahneman, his longtime collaborator and dear friend. Human Irrationality is Kahneman's great theme. That 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 baser — unconscious MMHG. FAST ASO SLOW By Daniel Kenna 499 pp. Fury. Straus & Giant. $30. 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 Ion ger 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 eco nomic models have traditionally assumed; they do not "maximize utility' The two then d ....Iusa.d an alterna- tive account of decision making, one more faithful to hu- man psychology, which they called "prospect theory.' (It was for this achievement that Kalmernan was awarded the Nobel) In the third phase of his carver, mainly after the death of Wersky, Kaluwman has delved into %Sonic psychology': the science of happiness. its nature and its causes. His findings in this area have proved disquiet- ing — and not just because one of the key experiments involved a deliberately prolonged colonoscopy. "Thinking, Fast and Slow- spans all three of these phas- es. It is an astonishingly rich book: lucid, profound, fulf of intellectual surprises and self-help value. It is consistent- ly 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 per- fection when you are never bored?) So impressive is its most of our judgments and actions are appropnate most of vision of flawed human reason that the New York Times overconfidence; it causes us to be more analytical. more the time; Kahneman writes In his introduction Yet, just vigilant in our thinking; to question stones that we would columnist David Brooks recently declared that Kahne- a few pages later, be observes that the work he did with man and ryerslirs work "will be remembered hundreds otherwise unreflectively accept as true because they are Tversky 'challenged' the idea, orthodox among social sci- facile and coherent. And that is why I frowningly gave of years from now; and that it is 'a crucial pivot point in entists in the I970s, that 'people are generally rational; the way we see ourselves; They are. Brooks said, 'like this extraordinarily interesting book the most skeptical The two psychologists discovered 'systematic errors in reading I could. the Lewis and Clark of the mind' the thinkuµ of normal people': errors wising not from Now, this worries me a bit A leitmotif of this book is System 2, in Kahnernan's scheme, is our stow, deliber- the corrupting ellecis of wooden: but built into our evolved ate. analytical and consciously effortful mode of reason- overconfidence. All of us, and especially experts, are cognitive machinery. Although Kahneman draws only ing about the world. System I. by contrast is our last, prone to an exaggerated sense of how well we under- modest policy implications(e.g,coritracts should be stated automatic_ intuitive and largely unconscious mode. It is stand the world — so Kahneman reminds us. Surely, he in clearer language), others — perhaps overconfidently? himself is alert to the perils of overconfidence. Despite System I that detects hostility in a voice and effortlessly — go Much further. Brooks. for example, has completes the phrase "bread ant all the cognitive biases, fallacies and illusions that he and argued that " It is System 2 that Kahneman and Trotsky's work illustrates 'the limits of so- swings into action when we have to fill out a to form or TWfskY (along with other researchers) Purport to have cial policy": in particular. the folly of government action to park a car in a narrow space. (As Kahneman and others discovered in the last few decades, he fights shy of the fight joblessness and turn the Li.vieniw around. bold claim that humans are fundamentally irrational. have found. there is an easy way to tell how engaged a Such sweeping conclusions, even if they are not en- person's System 2 is during a task; just look into his or Or Goes he? "Most of us are healthy most of the time,and dorsed by the author, make me frown. And :frowning — her eyes and note how dilated the pupils are.) as one learns on Page 152 of this book — activates the More generally, System I uses association and meta• Nalltat's new book "Why Does the World Exist?.; wU skeptic within us: what Kahneman calls 'System 2.* Just be put:tithednextspring. phor to produce a quick and dirty draft of reality. which putting on a frown. experiments show, works to reduce System 2 draws on to arrive at explicit beliefs and rea• EFTA01128843 sorted choices. System I proposes, System 2 &snow& So This might seem a minor point. But it applies to sev- he found that these two measures of happiness diverge System 2 would seem to be the boss, right? In principle, eral of the biases that Kabneman and Trersky, along with in surpnsmg ways. What makes the 'experiencing self' yes. But System 2, in addition to being more deliberate and other investigators, purport to have discovered in formal happy is not the same as what makes the 'remembering rational. Ls also lazy. And it tires easily. (The vogue term experiments. In more natural settings — when we are de- self' happy. In particular, the remembering self does not for this is 'ego depletion;) lbo often, Instead of slowing tecting cheaters rather than solving logic puzzles; when care about duration — how long a pleasant or unpleasant things down and analyzing them, System 2 is content to we are reasoning about things rather than symbols: experience lasts. Rather, it retrospectively rates.an expe- accept the easy'but unreliable story about the world that when we are assessing raw numbers rather than percent- rience by the peak level of pain or pleasure in the course System) feeds to it. 'Although System 2 believes itself to ages— people are fax less likely to make the same errors. of the experience, and by the way the experience ends be where theaction is; Kabneman writes. 'the automatic So, at least, much subsequent research suggests. Maybe These two quirks of remembered happiness — "dura. System I is the hero of this book' System 2 is especially we are not so irrational after all tion neglect' and the 'peak-end rule" — were strikingly seno. quiescent, It seems, when your mood H a happy one. Some cognitive biases, of course, are flagrantly exhib- illustrated in one of Kahnentana more harrowing experi- ited even in the most natural of settings. Take what Kah- ments. two groups of patients were to undergo painful A Tibia pap, the skeptical reader might wonder how neman calls the 'planning fallacy': our tendency to over- colonoscopies. The patients in Group A got the normal to take all this talk of System I and estimate benefits and underestimate costs, and hence procedure. So did the patients in Group B. except — with- System 2. Are they actually a pair of little agents foolishly to take on risky projects. In 2002, Americans re- out thee being told — a few extra minutes of mild discom- in our head, each with its distinctive personal- modeling their kitchens, for example, expected the job to fort were added after the end of the examination. Which ty? Not really, Says Kahneman Rather, they are 'Useful cost $18,658 on average, but they ended up paying $58,768. group suffered more? Well. Group B endured all the pain fictions" — usefial because they help explain the quirks of The planning fallacy is - only one of the manifestations that Group A did, and then some. But since the prolong- the human mind: of a pervasive optimistic bias,' Kahneman writes, which ing of Group B's oalonoscopies meant that the procedure To see how, consider what Kahneman calls the 'best- 'may well be the most significant of the cognitive biases' ended less painfully, the patients In this group retrospec- known and most controversial' of the experiments he Now, in one sense, a bias toward optimism is obviously tively minded it less. (In an earlier research paper though and Tversky did together:- "the Linda problem? Partici- bad, since it generates false beliefs — like the belief that not in this book, Kahneman suggested that the extra pants in the experiment were told about. an imaginary we are In control, and not the playthings of luck. But with- discomfort Group B was subjected to in the experiment young woman named Linda, who is single, outspoken and out this 'illusion of controL' would we even be able to might be ethically justified if It Increased their willing- very bright, and who, as a student. was deeply concerned get out of bed in the morning? Optimists are more pay- ness to come back for a follow-up!) with issues of discrimination and social justice. The par- As with coknoscopies, so too with life. It is the remem- ticipants were then asked which was more probable: (I) bering self that calls the shots, not the experiencing self Linda is a bank teller. Or (2) Linda is a bank teller and is The two psychologists discovered Kahneman cites research showing, for example, that active In the feminist movement. The overwhelming re- `systematic errors in the thinking of a college student's decision whether or -not to repeat a sponse was that (2) was more probable; in other words. spring-break vacation is determined by the peak-end rule that given the background information furnished. "femi- normal people.' applied to the previous vacation, not by how fun (or mis- nist bank teller' was more likely than 'bank teller.' This erable) it actually was moment by moment. The remem- Is, of course, a blatant violation of the laws of probabil- chologically resilient. have stronger Immune systems, bering self exercises a sort of 'tyranny' over the voice- ity. (Every feminist bank teller Ls a bank teller; adding and live longer on average than their more reality-based less experiencing self. 'Odd as it may seem,' Kahneman a detail can only lower the probability) Yet even among counterparts. Moreover, as Kahneman notes, exagger- writes,- I am my remembering sell, and the experiencing students in Stanford's Graduate School of Business, who ated optimism serves to protect both individuals and or- self, who does my living, is like a stranger to me' had extensive training in probability, 85 percent flunked ganizations from the paralyzing effects of another bias, the Linda problem One student, Informed that she had 'loss aversion': our tendency to fear losses more than we K AHNEMAN'S y conclusion, radical as it sounds, committed an elementary logical blunder, responded, 'I value gains. It was exaggerated optimism that John May- may not go far enough. There may be no expo, thought you just asked for my opinion." nard Keynes had in mind when he talked of the 'animal riencing sell at all. Brain-scanning experiments What has gone wrong here? An easy question (how co- spirits* that drive capitalism. Rafael MaLsch and his colleagues at the Weiz- herent is the narrative?) is substituted for a more difficult Evenif we could rid ourselves of the biases and illusions mann Institute in Israel, for instance, have shown that one (how probable is it?). And this, according to Kahne- identified In this book — and Kahneman, citing his own when subjects are absorbed in an experience, like watch- man, is the source of many of the biases that infect our lath of progress In overcoming them, doubts that we can ing the 'The Good. the Bad, and the Ugly: the parts of the thinking. System I jumps to an intuitive conclusion based — it is by no means clear that this would make our lives brain associated with sell consciousness are not merely on a 'heuristic' — an easy but imperfect way of answer- go better. And that raises a fundamental question: What quiet. they're actually shut down ('inhibited') by the rest ing hard questions — and System 2 lazily endorses this is the point of rationality? We are, after all. Darwinian of the brain. The self seems simply to disappear. Then heuristic answer without bothering to scrutinize whether survivors. Our everyday reasoning abilities have evolved who exactly is enjoying the film? And why should such it is logical. to cope efficiently with a complex and dynamic environ- egokss pleasures enter into the decision calculus of the Kahneman describes dozens of such experimentally ment. They are thus likely to be adaptive in this environ- remembering self? demonstrated breakdowns in ratlonalny — 'base-rate ment. even if they can be tripped up in the psychologist's Clearly, much remains to be done in hedonic psycho) neglect; "availability cascade," 'the illusion of validity' somewhat artificial experiments. Where do the corms of ogy. But Kahneman's conceptual innovations have laid and so on. The cumulative effect is to make the reader rationality come from, it they are not an idealization of the foundation for many of the empirical findings he re- despair for human reason. the way humans actually reason in their ordinary lives? ports in this book: that while French mothers spend less Are we really so hopeless? Think again of the Linda Asa species, we can no more be pervasively biased in our time with their children than American mothers, they problem. Even the great evolutionary biologist Stephen judgments than we can be pervasively ungrammatical in enjoy It more; that headaches are hedonically harder on Jay Gould was troubled by it As an expert in probabil- our use of language —or so critics cif research like ICahne- the poor; that women who live alone seem to enjoy the ity he knew the right answer, yet he wrote that 'a little man and Tversky's contend. same level of well-being as women who live with a mate; homunculus in my head continues to jump up and down. Kalinetrian never grapples philosophically with the na- and that a household income of about 575.000 in high-cost shouting at me — 'But shecan't just be a bank teller; read ture of rationality. He does, however, supply a fascinating areas of the country is sufficient to maximize happiness. the description*" It was Goad's System I, Kabneman as- account of what might be taken to be its goal: happiness. Policy makers interested In lowering the misery index of sures us, that kept shouting the wrong answer at him. But What does it mean to be happy? When Kahneman first society will find much to ponder here. perhaps something more subtle is going on. Our every- tor* up this question. In the mid 1990s. most happiness . By the time I got to the end of "Thinking, Fast and Slow," day conversation takes place against a rich background research relied on asking people how satisfied they were my skeptical frown had long since given way to a gran of of unstated expectations — what linguists call "Impti. with their life on the whole. But such retrospective as- intellectual satisfaction. Appraiiing the book by the peak- catures? Such implicatures can seep Into psychological sessments depend on memory. which is notoriously un- end rule, I overconfidently urge everyone to buy and read experiments. Given the expectations that facilitate our reliable. What if, instead, a person's actual experience of it. But for those who are merely interested in Kahnernana conversation, It may have been quite reasonable for the pleasure or pain could be sampled from moment to mo- takeaway on the Malcolm Gladwell question it is this: If participants in the experiment to take 'Linda Is a bank ment. and then summed up over time? Kahneman calls you've had 10.000 hoursof training in a predictable, rapid- clerk' to imply that she was not in addition a feminist. If this "experienced' well.being, as opposed to the "remem- feedback environment — chess, (refighting, anesthesiol- so, their answers weren't really fallacious. bered' well-being that researchers had relied upon. And ogy — then blink In al/ other cases, think U THE HEW YORK TIMES BOOK REVIEW Ir EFTA01128844