Book review, The Undoing Project (a project on thinking about thinking) -
The Undoing Project (Saenggak-e gwanhan saenggak project)
Daniel Kahneman, the Nobel laureate in Economics, and his close partner Amos Tversky. Their research, which evolved into behavioral economics, was published as Thinking, Fast and Slow and made a worldwide impact. Two men of completely opposite temperaments
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Hidden behind monetary utility and the halo effect of these scholars, I think I had only known the side branches that lay obviously visible at my feet—the kind of facts so plain they seemed reliable. The publication of one book, and the fierce research that became its backbone. And in the middle of all that, Danny and Amos standing face to face. Their lives as individuals carried a story as sincere and dramatic as their passion itself.
Thinking about thinking,
While organizing this material, an obvious truth struck me: psychology is the psychology of human beings. And yet, behind thick theories and a thicker reputation, I felt I had failed to truly see the person.
1. The background behind the publication of The Undoing Project
2. About Danny, the author of Thinking, Fast and Slow
3. About Amos, co-researcher of Prospect Theory
4. The collaboration, between cool reason and warm passion
? 5. That person— even after he leaves me
An interview, dazzling— of fathomless depth
Schorr tracked down Danny and Amos in August 1983, in Anaheim, California. The two were attending an American Psychological Association convention. At the time, Danny was 49 and Amos was 46. They spoke with Schorr together for several hours, and then for several more hours each, separately. They walked carefully through the history of their collaboration, starting from the early days when their work had been most exhilarating.
Amos told Schorr, "From the very beginning, we were able to answer questions no one had asked. We pulled psychology out of its forced laboratory setting and worked through it from everyday experience." Schorr asked whether their work had influenced the newly emerging field of artificial intelligence. "Not really. Instead of artificial intelligence, we study natural stupidity."
"Things have been hard since I got married, and since coming to America," Danny confessed. Amos still hedged, but after Schorr spent a long time talking with both of them, it became clear that the two had run into many problems since leaving Israel six years earlier. Right in front of Amos, Danny launched into a long account of his frustrations—how badly outsiders misunderstood the nature of their collaboration. "People think I serve Amos, but that's not true." He addressed Amos as much as Schorr. The one who loses out in this collaboration is, of course, me. Yes, you've contributed too, no question. The formal analysis isn't my strong suit, and that part shows up vividly in our work. But my own contribution isn't all that special."
More concisely than Danny, Amos explained why their unequal standing was, of course, the fault of others. "Apportioning credit is extremely difficult. It's draining and exhausting work in itself, and the outside world doesn't help collaborations. People keep prodding, hoping one of the two will fall away. That's the rule of equilibrium—but a joint enterprise is an unbalanced structure. It isn't stable. People can't stand it."
Danny didn't think the problems in his relationship with Amos were entirely the fault of outsiders. "In academia there are spoils when you succeed, and in the end one person walks away with all of them, or with most. That's just how it works—the field is that pitiless. Tversky doesn't rein it in. I doubt he even wants to." Danny opened up honestly about how he felt watching Amos take the bigger share of the glory they'd built together. "I am very much in Amos's shadow, and yet our actual relationship isn't like that. That's what stresses me. I get jealous! It's truly mortifying. To feel jealous, of all things— I detest that emotion…. I think I'm saying too much right now."
America— first steps in the job market. And the beginning of a divergence
Amos would later tell people that he had imagined which choice he might regret— Harvard or Stanford. If he picked Harvard, he would regret missing the weather and lifestyle of Palo Alto where Stanford sat, and he would resent the commute. If he picked Stanford, for a brief moment he might regret not being called a Harvard professor— a regret that, had he factored in the fact that Danny needed to be near him, he would not have entertained at all.
In reality, however, Stanford showed not the slightest interest in Danny. Ross said it bluntly. "There was a practical issue. Did we really need two people working on the same research? Cold logic said: hire only Amos, and you'd effectively get both Danny and Amos."
Danny had probably hoped to go to the University of Michigan together with Amos, but Amos was uninterested in anywhere besides Harvard and Stanford. After Harvard and Stanford turned Danny down, and Berkeley too signaled it had no plan to hire him, Danny settled in alongside (his wife) Anne at the University of British Columbia in Vancouver. Danny and Amos agreed to take turns flying to see each other on weekends.
And yet, perhaps because the gap was small at the very first step and so didn't really sink in, or perhaps because the relative deprivation was still a fresh, not yet accumulated thing— it didn't quite register.
Skewed external evaluations
In 1984, when the call came that Amos had been awarded the MacArthur "genius" grant, he was on a short stay in Israel. Along with the $250,000 prize, the award came with $50,000 in research funds and premium medical services. The press release celebrated Amos as a thinker who had displayed "extraordinary originality and dedication to creative pursuits, and a marked capacity for self-direction." The only piece of Amos's research cited in the press release was the work he had done with Danny. Yet Danny was not mentioned.
Amos disliked awards. He thought they exaggerated differences among people, did more harm than good, and inevitably produced more disappointment than joy because there were always many people besides the recipient who deserved or felt they deserved the prize. The MacArthur was exactly that.
Along with the awards, articles and books extolling Amos's accomplishments poured in, and they often praised joint work with Danny as if it were Amos's solo research. Even when collaborations were mentioned, Danny's name came second. Tversky and Kahneman.
Danny couldn't help but notice that Amos was attracting renewed attention thanks to their joint research. Economists wanted to invite Amos to their conferences, and linguists, philosophers, sociologists, even computer scientists wanted to invite him too.
Danny confided in Miles Shore. "When you don't get invited to those conferences, even if you didn't want to go, you feel resentful. If Amos hadn't been invited to so many conferences, my life would have been a little better."
A Lucky Day in America
At the time, Danny was still riding high. He said, "We had finished Prospect Theory and were starting on framing effects, so we were on top of the world. Who could possibly beat us, I thought. Back then, there wasn't a shadow between us." Danny watched Amos give the customary candidate's lecture for a Stanford professorship. This was the first lecture after Stanford had offered Amos a professorship in what was probably the shortest turnaround in the school's history. In his lecture, Amos introduced Prospect Theory, which he had developed with Danny. Danny said, "I just felt so proud of Amos. I should have been jealous, but somehow I wasn't."
But things no one had foreseen began to happen. Their relative status started to widen dramatically. When Amos visited the University of British Columbia, he carried himself a bit haughtily. Danny went up to Palo Alto; Amos came down to Vancouver. "Amos had a tendency to look down on others. I could tell he saw Vancouver as quite the backwater," Danny said.
One night, talking late, Amos suddenly said that the difference he felt at Stanford was that everyone there was first rate. Danny remembered the moment this way: "That was the start. Amos didn't mean anything grand by it, and I'm sure he regretted it himself— but Amos felt a slightly arrogant kind of sympathy, and I couldn't help but be wounded."
In 1978–1979, as Danny was leaving Palo Alto for Vancouver to start the school year, he was struck again by the unexpected luck life had handed him. On the other side of the planet were two children, an old laboratory full of former colleagues, and a society he once thought he belonged to. He had left it behind, leaving his ghost in Israel. "Whenever I was thinking about something, beneath my thoughts there was always the awareness that I had been changing my own life all along. I'd even changed wives."
I am always living by assuming the opposite of the facts.
I keep comparing my life as it is to the life it could have been."
As he was looking back at his own past, Danny suddenly recalled his nephew Ilan, who had lost his life in a fighter-jet crash five days before being discharged from the military. Looking back, those who had loved Ilan after his death felt an urge to undo, in their minds, that fighter-jet crash, and Danny couldn't help but pay attention to that powerful urge.
Many of the sentences they spoke aloud could begin with "if."
A — If only Ilan had been discharged a week earlier, if only Ilan had been at the controls when the pilot was blinded by flames, people coped with the loss in their minds by drifting through imaginary paths in which the loss had not occurred at all. And yet, to Danny, this drifting did not look random. There seemed to be certain constraints in how the mind constructed substitute realities.
B — If, when the accident happened, Ilan had had a year of service left, no one would have said "if only he had been discharged a year earlier." No one said, "If only the pilot had caught the flu that day," or "If only Ilan's plane had failed to take off because of a mechanical defect." Going further, no one even said, "If only Israel had had no air force." All of those counterfactual assumptions would have saved his life, but those thoughts simply didn't occur to the people who loved him.
There are surely more than a million ways the plane crash could have been avoided, but people seemed to consider only a handful of them.
The imagined scenarios people invented to undo Ilan's tragedy followed a certain pattern, and that pattern resembled the patterns Danny himself used to imagine in his own "different lives."
As soon as he arrived in Vancouver, Danny asked Amos to send him whatever notes Amos had once jotted down about regret, when the two of them used to debate it. Back in Jerusalem, the two had spent more than a year discussing the rules of regret. They had been mainly interested in how people anticipated unpleasant feelings in advance, and how that anticipation reshaped their choices.
Now Danny wanted to look at regret and other emotions in the opposite direction. In other words, he wanted to study how people undo events that have already happened. He and Amos could already imagine how this kind of work would feed back into their research on judgment and decision-making.
The constraints of heuristics, the rules of imagination
After the availability heuristic, the representativeness heuristic, and anchoring, Danny came up with a fourth heuristic. And he finally gave it a name: 'the simulation heuristic.' It is a heuristic concerning the power of unrealized possibilities— the kind of possibilities that unsettle people's minds.
As they go through life, people simulate the future. "What if I stop pretending to agree and just say what I really think? What if they hit the ball toward me and the grounder slips between my legs? What if I refuse his offer instead of accepting it?" In other words, people make judgments and decisions on the basis of various imagined scenarios. But not every scenario is equally easy to imagine. Constraints come into play here.
Just as constraints had appeared in people's minds when they tried to 'undo' a tragedy, find the rules that emerge when, after something happens, people try to undo it in their heads. As a bonus, you might also figure out how, before something happens in reality, people simulate it in their minds.
Alone in Vancouver, Danny threw himself into a newly awakened interest in the distance between 'the world that exists' and 'the world that didn't exist but could have'. Much of what he and Amos had researched had been about finding systems or rules in domains where no one had even tried to look for them. Now, once again, that opportunity had come. Danny wanted to investigate the way people undo reality and look for its alternatives. Put simply, he wanted to find the rules of imagination.
Everyone seemed to feel that the cause of their anger was not exhausted by reality alone. What fueled the emotion was the proximity of an alternative reality— how 'close' Mr. Tees had come, in time, to making his flight. Danny wrote this down in preparing a lecture on the topic. "Mr. Tees is angrier for the simple reason that the probability he 'would have caught' the plane that 'left only five minutes earlier' is higher. There is something Alice-in-Wonderland about these examples— a strange mixing of reality and fantasy. Mr. Crane, who can imagine a unicorn that doesn't exist if he wishes, why is it that he can't imagine himself avoiding a thirty-minute delay, and so can't contain his anger? Clearly, the freedom of fantasy is constrained."
What Danny was beginning to investigate was precisely those constraints. He wanted to properly examine what is now called 'counterfactual emotion.' Counterfactual emotion is the kind of emotion that, in order to escape pain, prods us to construct an alternative reality that contradicts what actually happened. Regret is the most obvious counterfactual emotion, but frustration and envy share its essential character.
In a letter to Amos, Danny called such emotions "emotions arising from unrealized possibilities." Those emotions could even be described in simple math: Danny said that the intensity of the emotion is the product of two variables — 'the desirability of the alternative' and 'the feasibility of the alternative'.
Undoing the experiences that produce regret and frustration isn't always easy. The frustrated person had to undo some of the surrounding circumstances, while the regretful person had to undo their own actions. Danny also wrote: "Yet the basic rules of undoing apply equally to frustration and regret. Both require a more or less plausible path to the alternative state."
Envy was different. Envy required not even the slightest effort to imagine a path to the alternative. Danny wrote: "The availability of the alternative seems to be governed by the similarity between you and the object of your envy. To feel envy, all you need is to be able to vividly imagine yourself in the other person's situation. You don't need a plausible scenario to explain how you got there." In some odd way, envy didn't even require imagination.
Imagination
Imagination is not a flight to infinite destinations. It is a tool for taking the world of infinite possibility and trimming it into a sensible world. Imagination follows the rules of undoing. One such rule is that the more there is to undo when you build an alternate reality, the less likely it is that your mind will undo it.
A death from a massive earthquake seemed harder to undo than a death from a lightning strike. To undo the earthquake, you would have to undo everything the earthquake had caused.
In his letter, Danny wrote: "The more consequences an event has, the greater the change required to remove that event." A related rule was that "the older the event, the harder it is to change." Over time, an event's consequences pile up, and there is more to undo. The more there is to undo, the less the mind even attempts to undo the event. At that point, you feel that nothing could have been done differently— and this is probably one of the ways time heals wounds.
The Focus Rule
A more general rule was what Danny named the 'Focus Rule.' He wrote in his letter, "We have a tendency to imagine an actor or hero moving within a fixed situation. If possible, we hold the situation constant and move the actor. … We don't conjure up a sudden gust of wind to deflect Oswald's [the Kennedy assassin's] bullet." The exception to this rule was when, in the fantasy of undoing an event, the protagonist was oneself was the case. In that case, instead of one's actions, one tried to undo the situation. "Changing or replacing oneself is far harder than changing or replacing other people."
Danny wrote in his letter, "The world in which I would assign myself a new set of qualities would, naturally, be far from the world I actually live in. I have a bit of latitude, but I cannot freely become someone else."
The most general rule of undoing had to do with what was surprising or unexpected.
A middle-aged bank executive, who took the same route to work every day, one day took a different route. A young man driving a pickup truck under the influence of drugs ran a red light, struck the executive's car from the side, and the executive died.
A — When people were asked to undo this tragedy, their thoughts naturally fell on the route the bank executive had chosen that day. If only he had gone the usual way!
B — But when the bank executive was placed back on his usual route, the drug-addled young man was put in the same truck, and it was instead supposed that the executive had run a red light on his usual route, no one thought, "If only he had taken a different route to work that day!"
The mental distance you traveled when moving from a usual way of doing things to a less usual way was much greater than the distance traveled in the opposite direction.
When the mind undoes an event, it tends to remove what is surprising or unexpected. This isn't to say it follows the rules of probability. A much easier way to save the man would be to alter the timing. If either the bank executive or the young man had arrived at the moment of the tragedy a few seconds earlier or later, the two would never have collided. Yet, when undoing the event, people didn't think this way. It was much easier for them to undo the exceptional element.
Danny wrote to Amos that "it's amusing to undo Hitler in your imagination," and discussed what recent history might have looked like if Hitler had realized his original dream and become a painter in Vienna. "Let's imagine one more counterfactual snapshot. Before conception, the chance Hitler would be born female was also fifty-fifty. The probability that he'd grow up to be a great painter was probably no higher than the probability he'd be born a woman. So among these ways of undoing Hitler, why does one feel quite acceptable while the other feels nonsensically shocking?"
Amos seemed interested in Danny's new ideas, but for some reason, he didn't add anything of his own.
For some time, Amos and Danny had honestly faced their own everyday mistakes and emotions, looking for the psychological causes and rules behind them. Amos, with his marriage, had reluctantly settled in America, and Danny felt sorry for him and felt compassion for him. And yet, all the evaluations from the outside concentrated solely on Amos. If Danny could only face that attention from an omniscient narrator's perspective— from the position of someone who had become a stranger — perhaps Danny was performing his own kind of 'undoing,' on himself.
In the midst of all this, Danny began studying his own emotions— regret, undoing, imagination. But Danny's emotions were probably not something he could share with Amos. And after reading what Danny had written about his research, Amos must have already, intuitively, read Danny's feelings. Could that have been the background for Amos being unable— or unwilling— to readily contribute his own thoughts?
Frustration
But the emotion that overwhelmed Danny was frustration. For most of the past ten years, Danny had come up with ideas while Amos was around. Whenever one of them had an idea, he immediately shared it. Then the idea would be received uncritically, and a kind of magic would happen— two minds becoming one. Danny once told Miles Shore, "I start a lot of things, but the fruits of them always seem to slip out of my hands." By rough analogy, the division of roles was something like Danny as the planner, Amos as the developer.
And now Danny was working alone again, and he felt that there was no one to develop his ideas. Danny said, "I'm overflowing with ideas, but Amos isn't there. So the ideas just got thrown away. The one who could give them shape was Amos, and I couldn't get that help."
A few months after Danny's letter to Amos, in April 1979, the two were scheduled to give a joint lecture at the University of Michigan. For Danny, this lecture was the first occasion to publicly share what he had been thinking during the nine months he and Amos had been apart. He called it 'The Psychology of Possible Worlds.' "We are going to look at the role unrealized possibilities play in our emotional reactions to reality, and in our understanding of reality."
Danny explained the rules of undoing. He had prepared many test stories for the audience. Beyond the bank executive killed in a car crash caused by a drug-addled young man, there were many other unfortunate people. There was, for example, a man who had a heart attack and so couldn't press the brake and died.
After the lecture, people lingered, reluctant to leave, milling about the room.
Clyde Coombs, who had long been a kind of mentor to Amos, came up to the two with eyes full of curiosity.
"Where on earth did all those ideas come from?"
And Amos answered. "Danny and I don't talk about things like that."
That was the moment when the story unfolding in Danny's head began to change.
Danny and I don't talk about things like that
Later, Danny would say this was the moment when their relationship began to end. And when, later, he tried (using his own theory) to undo this moment, he didn't say things like, 'If only Clyde Coombs hadn't asked that question,' or 'If only I had been as hard-hearted as Amos,' or 'If only I had never left Israel in the first place.' What he said was: "If only Amos had been humble." In Danny's imagination, Amos was the actor, the focus of attention.
By this point, when Professor Coombs was praising Danny right beside him, if Amos had even slightly chimed in— at least this once, after Danny had himself prepared the work, there was a chance to acknowledge his contribution— but Amos didn't even try to seize that chance. After the Michigan lecture, Danny gave several more talks on the undoing project, and rarely brought up Amos at all. That had never happened before.
In his head, the possibility of a different story unfolds. "I had hoped Amos would lean on the situation to repair our relationship, but he didn't. He didn't even acknowledge the need to." Danny said.
Separation— or perhaps decomposition
For about ten years, the two had laid down the strict rule that they would not even invite a third party near their domain of interest. Then, in late 1979 or early 1980, Danny began telling Dale Miller, a young assistant professor at the University of British Columbia, his thoughts on how people compare reality to its alternatives. When Miller asked about Amos, Danny answered that they no longer worked together.
Miller said, "Professor Danny was in Amos's shadow, and he seemed deeply troubled by it." Before long, Danny and Miller began to write papers together.
You could call it the Undoing project. "It seemed that the two had agreed to find someone else. And Professor Danny kept emphasizing that the collaboration with Amos was now over. I remember many anxious conversations. Once, he told me to be gentle with him.
It would be the first relationship after Amos, he said..
The unspoken secret
Meanwhile, Amos, in Russia, in an unheated, bugged hotel room, spent his time elaborating a document he had named the 'Undoing Project.' This handwritten document eventually grew to about forty pages. Reading it, you can hear, between the lines, the sound of a diamond-cutter quietly clearing his throat as he waits for the rough stone. Clearly, Amos was hoping to turn Danny's ideas into a complete theory. Danny didn't know this; he didn't know Amos was busy generating examples.
Without answering Danny's long letters, Amos was alone making notes, organizing the ideas that Danny had been pouring out.
It was a very basic question of decision theory: a story about the things one didn't choose. He agonized over the title. The title had to be set before he could get a feel for what to write. In his earliest notes, he had scrawled 'Undoing Heuristic.' After he developed a theory, he called it 'Possibility Theory.' Then 'Scenario Theory,' then 'Theory of Alternative States.' In his last memo on this subject, he called it 'Shadow Theory.'
Amos wrote: "The point of Shadow Theory is that the context of various alternatives, or the set of possibilities, determines not only our emotional state but also our expectations of reality, our interpretations, our recollections, and our causal analyses." Concluding his thoughts on the subject, he summed up much of it in a single sentence: "Reality is a cloud of possibilities, not a point."
It wasn't that Amos lacked interest in Danny's ideas. It was just that the two were no longer talking with the door shut behind them in the same room. The conversations they would once have had together, they now had alone. Because of the new distance between them, it had become possible to identify, more precisely than ever, whose idea was whose.
Amos used to confide his frustrations to Miles Shore. "We don't know who came up with which idea. We're physically apart, and the ideas are written down in letters. Before, when an idea came to mind, the first thing we did was pick up the phone. Now we develop ideas alone, get absorbed in them alone. As that happens, the ideas become more personal, and each remembers them as his own. We never used to do that."
As Danny became absorbed in his new ideas, rather than letting Amos break them down and reconstruct them as if they were his, he held them back. Amos still flew to Vancouver every weekend, but a new tension had settled between them. Amos clearly wanted to believe that they could collaborate as before. But Danny no longer did.
Deploy and CS
As soon as Amos and Danny arrived in North America, they jointly published a stack of papers. Most were things they'd been working on when they left Israel. But by the early 1980s, the way they wrote papers together had changed. Amos wrote one paper on loss aversion under both their names, and Danny added a few peripheral paragraphs to it.
Danny finished by himself what Amos had been calling the 'Undoing Project,' titled it 'The Simulation Heuristic,' put both of their names at the top, and published it in a volume that gathered together their other papers and contributions from students and colleagues (after that, instead of working with Amos, he began exploring the rules of imagination with Dale Miller, a younger colleague at the University of British Columbia).
Amos, meanwhile, wrote a paper aimed directly at economists, revising the technical details of Prospect Theory. Its title was 'Advances in Prospect Theory,' and he worked on it mostly with his graduate-student protégé Rich Gonzalez, but it appeared in a journal under the names of Danny and Amos.
In this manner, the two never quite dispelled the impression that they were still working together as they once had— even as the forces pulling them apart grew stronger. But as their common adversaries multiplied, the two did not draw closer. Danny grew increasingly uncomfortable with how Amos treated those who disagreed with their views.
The Linda experiment, and the difference between T and F
Amos was born to be combative; Danny was born to endure. Danny avoided clashes. Rather than argue with attackers, Danny focused on developing experimental cases that everyone would have to accept. The experiment that came out of this was the Linda experiment.
From among eight items describing Linda, four items were given, and people were asked to estimate, item by item, the probability that Linda fit each. The items given to Group A included "Linda is a bank teller," while those given to Group B included "Linda is a bank teller and active in the feminist movement." Of course the students didn't catch on, but among the eight descriptions, only those two items were the key. The result: the probability Group B assigned to "Linda is a bank teller and active in the feminist movement" was higher than the probability Group A assigned to "Linda is a bank teller."
The heuristic people use when judging probability led to wrong judgments. Once a logic is structured into a story,people fail to recognize that logic. In situations like this, the force that clouds people's judgment is what Danny and Amos called 'representativeness.' It is the similarity between the object of judgment and the representative image of that object held in people's minds.
In the first Linda experiment, the students fixed their thoughts on the description of Linda, and compared the specific descriptions, item by item, to the typical image of 'a person involved in the women's movement' that they had in their heads. They concluded that the special case of being a bank teller and active in the feminist movement was more probable than the general case of being merely a bank teller.
Amos was not satisfied with that. He kept varying the subjects and continuing the experiments. To win the argument, people had to be shown to actually commit the error. According to the experiments, even doctors committed the very same mistake as the students, by an overwhelming majority. Amos and Danny wrote, "Most of the participants seemed surprised and disappointed by the fact that they had committed a basic logical error.
The conjunction fallacy. It's such a common error that those who fell into it expressed regret— they should have been a bit more careful. Amos must have felt that this paper on the 'conjunction fallacy,' which he had begun co-writing with Danny, would be the debate-closer. In other words, he must have thought it would put an end to the argument over whether humans think according to probability— or, as Danny and Amos claimed, otherwise.
Amos and Danny carefully explained why and how people fail to obey "perhaps the simplest, most basic law of probability." The reason people choose the more specific description, even though it is less probable, is the 'representativeness' of that description. The two men pointed out fields where this mental flaw could lead to serious real-world consequences. For instance, when a forecast is internally consistent and described in detail, it can seem more credible even though its probability is lower. And when a lawyer adds a 'representative' detailed description to a person or an event, even if it is less factual, the persuasiveness of the case can be raised in an instant. Amos and Danny once again demonstrated, comprehensively, the power of the heuristic at work in our minds. The strange force they had named the 'heuristic.'
Danny couldn't make up his mind about this new project, or about Amos. From the moment they had left Israel, the two had been like swimmers caught in different currents, with no strength left to swim away from each other.
Amos was drawn to logic; Danny was drawn to psychology. Danny didn't share Amos's enthusiasm for proving human irrationality. Danny's interest in decision theory ended at the psychological insight required for it. Later, Danny would say, "It's a fundamental argument. Are we doing psychology now— or decision theory?" Danny wanted to go back to psychology.
Strong? Adversary
In October 1993, Danny and Amos happened to attend the same conference in Turin, Italy. One evening, while taking a walk together, Amos asked a favor. The German psychologist Gerd Gigerenzer was once again drawing attention by criticizing their work. From the start, those who had been most upset by Danny and Amos's research argued that the two had focused only on mental errors and exaggerated the flaws of human thought.
But to Danny and Amos, Gigerenzer ignored the conventional rules of intellectual combat, and so he distorted their work, making them appear to hold a deeply fatalistic view of humanity. He even wholesale ignored almost all of the strongest evidence the two had presented. As critics sometimes do, he depicted the object of his contempt not as it was but as he wished it to be, and then attacked it as wrong.
Danny recalled it later. "Amos said we absolutely had to retaliate against Gigerenzer, and I said, 'I don't feel like it. It'll take a lot of time. It'll make me very angry. I hate getting angry. And we won't really win anyway.' And then Amos said, 'I have never once asked you for anything as a friend. I'm asking you now, as a friend.' I thought to myself: 'No, he never has. I can't refuse.' And it wasn't long before Danny thought he should have refused. Amos didn't just want to refute Gigerenzer; he wanted to demolish him entirely.
Gigerenzer endorsed an idea known as evolutionary psychology. Evolutionary psychology is the notion that the human mind, having evolved to fit its environment, must be highly well-adapted to that environment. If so, of course it wouldn't easily display systematic biases. Amos thought this idea was nonsense. The human mind is less a perfectly engineered tool than a coping mechanism. Amos once said, in a lecture to Wall Street executives:
"Roughly speaking, the brain seems to be built to deliver as much certainty as possible. So rather than represent all the uncertainty in a given situation, it seems built to find the case that best fits a given interpretation." The human mind coping with uncertainty is like a Swiss Army knife. It can do almost any task, but it doesn't fit any single task perfectly— so it's hard to say it has 'evolved' to perfection. "Listen to an evolutionary psychologist long enough, and you'll stop believing in evolution," Amos said.
Danny wanted to understand Gigerenzer properly— and perhaps even to approach him. "I always sympathized more with the critics than Amos did. I have a tendency to almost automatically think from the other side's standpoint," Danny said.
In a letter to Amos, Danny suggested that Gigerenzer might be caught up in some confused emotion. Shouldn't they put their heads together and find a way to set him straight? Amos snapped back. "Even if so, you can't say that. I don't even believe that's the case…" Danny had "decided to help Amos as a friend, but it wasn't long before he tasted misery once again.
While they kept rewriting their rebuttal of Gigerenzer, the two also had to keep rewriting the dispute between themselves.
Divorce
Danny's language was always too soft for Amos, and Amos's language was too rough for Danny. Danny was always the soother, and Amos was the agitator. There was nothing where the two truly met halfway.
Danny: Danny wrote a letter to Amos. "Reopening the discussion of Gigerenzer's afterword makes me so uncomfortable… I'm in no mood to discuss this. And your mood feels too foreign to me." When Amos kept pressing him, four days later Danny added: "On the very day they announce the discovery of forty billion new galaxies, we are arguing over six words in an afterword. (...) It's truly astonishing that not even the number of galaxies can stop our debate over 'repeat' versus 'reiterate.'" And he wrote, "From now on, let's do this by email. After every conversation I stay angry for so long, this just won't work."
Amos: Then Amos wrote back. "I cannot understand your sensitivity. Ordinarily, you are more open and less defensive than anyone I know. And yet when I rewrite a sentence you like, you flare up in anger; when I write a sentence with no malice at all, you read it negatively against my intent and flare up again."
Danny: One evening in New York, while staying with Amos at his apartment, Danny had a dream. "In the dream, a doctor told me I had six months to live. I said, 'No one would ever have predicted I'd spend the last six months of my life studying this kind of garbage. It's just terrific.' The next morning, I told Amos about the dream."
Amos: Then Amos looked at Danny and said, "Anyone else would think that funny. Not me. Even if you only had six months to live, I'd want you to finish this work with me."
Not long after they had exchanged words like that, Danny saw the new member list of the U.S. National Academy of Sciences. Amos had been a member for nearly ten years. Once again Danny's name was missing. Once again the gap between the two was something anyone could see. "I asked Amos. Why don't you nominate me? It's not as though I don't know the reason." If their situations had been reversed, Amos would never have tried to gain anything by appealing to a friendship with Danny. Amos secretly viewed Danny's neediness as a weakness. "I told him: that's not how a friend acts." Danny said.
I told him: that's not how a friend acts
With those words, Danny walked away. He pulled out of everything. The Gigerenzer business, the joint research— all of it, finished. Danny told Amos that they were no longer even friends. Danny said, "It was a kind of divorce."
Two partings
Three days later, Amos called Danny and said he had some news. The tumor in his eye had turned out to be malignant melanoma. After thorough tests, the doctors found cancer everywhere. He had at most six months to live. Danny was the second person Amos told.
When Danny heard the news, something inside him sank. "Amos said, 'We are friends. No matter what you think of us.'"
We are friends. No matter what you think of us.
Amos told only a tiny circle about his approaching death.
Amos heard the news in February 1996, and from that point on he spoke of his life in the past tense. Avishai Margalit said, "Amos heard from his doctor that his life was over and called me. So I went to see him. He picked me up from the airport. We headed for Palo Alto, and on the way, we stopped at a scenic spot and talked about death and life. It mattered to Amos that he could control his own death. At that moment, Amos didn't seem to be talking about himself. He didn't talk about his death. There was a kind of detachment— it was truly astonishing. He said, 'Life is a book. There's no reason a thin book can't be a good book. It was a really good book.'"
Life is a book.
There's no reason a thin book can't be a good book.
It was a really good book.
Amos seemed to understand his early death as the price for having lived like a Spartan. For example, he told Varda Liberman the story of saving the life of a soldier who had collapsed unconscious onto an explosive. Liberman said, "He told me that this single incident had, in some way, decided his entire life. Amos said, 'After doing it once, I felt obligated to keep up that hero image. I had behaved that way before; now I had to live up to that image.'"
Amos took only a limited number of phone calls. One of them was from the economist Peter Diamond. Diamond recalled, "I'd heard Amos had only a few days to live. I'd heard he wasn't taking calls. But I had just finished the report I was sending to the Nobel committee." He wanted to let Amos know that he had become one of the few finalists for the Nobel Prize in Economics, to be awarded that fall. But the Nobel Prize is given only to the living. Diamond couldn't recall Amos's reply, but Varda, who was there when Amos took the call, remembered it. "Thank you very much for telling me. But I can say with certainty that the Nobel Prize is not something I will be regretting."
And the phone rang.
Danny stayed at Princeton. It was the place he had originally gone to in order to get away from Amos. After Amos died, Danny's phone rang more than ever. Amos had gone, but their work was alive, and people's interest only kept growing. When people referred to their joint work, they no longer said "Tversky and Kahneman." Now they began to say "Kahneman and Tversky."
And in the autumn of 2001, Danny was invited to come to Stockholm to give a presentation. Leading economists, along with members of the Nobel committee, were to attend. Apart from Danny, all the speakers were economists. Danny, along with a few of the others, was a strong candidate for the Nobel. "It was an audition, basically," Danny said. He prepared the talk meticulously.
He decided that the topic had to be something he hadn't done with Amos. Some of his acquaintances found that decision strange. After all, what had captured the Nobel committee's attention was their joint work. Danny explained: "I was invited because of the joint work, but I had to show that I was qualified on my own. The question is not whether the work is qualified, but whether I am."
Danny finished the lecture and returned to Princeton.
If by some chance he were to win the Nobel, it probably wouldn't be until the following year. They had now seen Danny in person and heard him speak. Now they would judge whether Danny deserved the prize. Every nominee knows the date when the early-morning call from Stockholm might come. If it comes at all. On October 9, 2002, Danny and Anne were together in their Princeton home. Half hopeful, half doubtful. Danny was writing a recommendation letter for his outstanding graduate student Terry Odean. Honestly, he had never seriously thought about what he would do if he won the Nobel. Or rather, he was deliberately trying not to. Having spent his childhood in wartime, he had cultivated an exuberant imaginary life. In his imagination, he was the protagonist. He led the war easily to victory and ended it easily.
But, in true Danny fashion, he set rules even for his imagination. Never indulge in fantasies about things that might actually happen. The reason he set this private rule was that, in the past, he had imagined what could really happen and then lost the drive to make it happen. His imaginings were so vivid that they felt like "actual experiences," and once you had actually experienced something, there was no reason to bother making it real. He would never end the war that had killed his father. So what harm was there in carefully crafting scenarios in which he easily led that war to victory.
Danny tried not to imagine what he would do if he were to win the Nobel. The phone hadn't rung; just as well. At one point Anne stood up and said, with a faint trace of disappointment, "Well, that's all right." Every year there was someone who got disappointed. Every year there was an old man waiting by the phone.
Anne went outside to exercise, and Danny was alone in the house. He had always been good at preparing himself for the moment of not getting what he wanted, and in the larger view, this wasn't a fatal blow. He was content with who he was and with what he had done. Now he could allow himself to imagine, freely, what he would have done had he won the Nobel. He would have brought his wife and children. He would have included a tribute to Amos in his acceptance speech. He might even have brought Amos to Stockholm. The thing Amos had never done for Danny— Danny would have done for Amos. There were many things Danny might have done if he had won the Nobel. But now there was something he had to do. He went back to his desk and resumed writing Terry Odean's recommendation letter.
And the phone rang.
Daniel Kahneman receiving his Prize from His Majesty the King at the Stockholm Concert Hall.
The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel 2002
The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel 2002 was divided equally between Daniel Kahneman "for having integrated insights from psychological research into economic science, especially concerning human judgment and decision
www.nobelprize.org
