The Undoing Project: A Friendship that Changed the World

Danny then had himself driven by an assistant around the country so that he could ask army officers to assign character trait ratings to their own soldiers—which he could then compare to the soldiers’ performance. Find the characteristics of the people who are good in a particular branch of the military, his thinking went, and you could use them to identify others who shared those traits and should be assigned to that branch. (His memory of his trip was typically unusual, preserving a curious detail rather than the broad picture. He didn’t recall much about his encounters with combat officers, but he remembered vividly what the driver had said after Danny had taken the wheel of the jeep. Danny had never before driven. After he braked in anticipation of a bump in the road, the driver praised him: “He said, ‘That is exactly the right gentleness.’”) From the combat officers in the field Danny learned that he’d been sent on a fool’s errand. The military stereotypes were false. There were no meaningful differences between the personalities of successful people in the different branches. The personality that succeeded in the infantry was more or less the same as the personality that succeeded beside an artillery piece or inside a tank.

The scores on Danny’s personality test did predict something, however. They predicted the likelihood the recruit would succeed in any job. They gave the Israeli army a better idea than it had before of who would succeed as an officer, or as a member of some elite service (fighter pilot, paratrooper), and who would not. (They also turned out to predict who would end up in jail.) Maybe more surprisingly, the results were only loosely correlated with intelligence and education—which is to say they contained information that those simple measures did not. The effect of what became known informally as the “Kahneman score” was to make better military use of an entire nation and, in particular, to reduce, in the selection of its military leaders, the importance of raw, measurable intelligence and increase the importance of the qualities on Danny’s list.

The process Danny created proved to be so successful that the Israeli military has used it right up to the present day with only minor adjustments. (When women were admitted to combat units, for instance, “masculine pride” became “pride.”) “They tried to really change it once,” says Reuven Gal, the author of A Portrait of the Israeli Soldier. Gal served for five years as chief psychologist of the Israel Defense Forces. “They made it worse, so they changed it back.” Upon leaving the army in 1983, Gal went to Washington, DC, on a National Academy of Sciences research associateship. There, one day, he had a call from a top general in the Pentagon. “He says, ‘Would you mind coming to talk to us?’” Gal went over to the Pentagon to be interrogated by a roomful of U.S. Army generals. They put their question in many different ways, but, Gal said, “It was always the same question: ‘Please explain to me how it is possible you guys use the same rifles we use, drive the same tanks we drive, fly the same airplanes we fly, and you are doing so well winning all of the battles and we are not? I know it’s not the weapons. It must be the psychology. How do you pick the soldiers for combat?’ For the next five hours they picked my brain about one thing: our selection process.”

Later, when he was a university professor, Danny would tell students, “When someone says something, don’t ask yourself if it is true. Ask what it might be true of.” That was his intellectual instinct, his natural first step to the mental hoop: to take whatever someone had just said to him and try not to tear it down but to make sense of it. The question the Israeli military had asked him—Which personalities are best suited to which military roles?—had turned out to make no sense. And so Danny had gone and answered a different, more fruitful question: How do we prevent the intuition of interviewers from screwing up their assessment of army recruits? He’d been asked to divine the character of the nation’s youth. Instead he’d found out something about people who try to divine other people’s character: Remove their gut feelings, and their judgments improved. He’d been handed a narrow problem and discovered a broad truth. “The difference between Danny and the next nine hundred and ninety-nine thousand nine hundred and ninety-nine psychologists is his ability to find the phenomenon and then explain it in a way that applies to other situations,” said Dale Griffin, a psychologist at the University of British Columbia. “It looks like luck but he keeps doing it.”

A different, more ordinary person would have left the experience brimming with confidence. In a stroke, twenty-one-year-old Danny Kahneman had exerted more influence upon the Israeli army—the institution on which the society depended for its survival—than any psychologist had ever done or ever would do. The obvious next step for him was to go off and get his PhD and become Israel’s leading expert in personality assessment and selection processes. Harvard was home to some of the leading figures in the field, but Danny decided, without anyone’s help, that he wasn’t bright enough to go to Harvard—and didn’t bother to apply. Instead he went to Berkeley.

When he returned to Hebrew University as a young assistant professor in 1961, after four years away, he was freshly inspired by personality studies being done by the psychologist Walter Mischel. In the early 1960s Mischel created these wonderfully simple tests on children that wound up revealing a lot about them. In what became known as the “marshmallow experiment,” Mischel put three-, four-, and five-year-old kids in a room alone with their favorite treat—a pretzel stick, a marshmallow—and told them that if they could last a few minutes without eating the treat they’d receive a second treat. A small child’s ability to wait turned out to be correlated with his IQ and his family circumstances and some other things as well. Tracking the kids through life, Mischel later found that the better a five-year-old resisted the temptation, the higher his future SAT scores and his sense of self-worth, and the lower his body fat and the likelihood he’d suffer from some addiction.

Gripped by a new enthusiasm, Danny designed a bunch of marshmallow test–like experiments. He even coined a phrase for what he was doing: the psychology of single questions. He arranged for Israeli kids on camping trips—this was just one example—to be offered a choice between sleeping in a single tent, a two-person tent, or an eight-person tent. Perhaps their answers, Danny thought, would say something about their tendency to affiliate with a group. The idea yielded either no findings or findings he couldn’t replicate in a subsequent experiment. And so he gave up. “I wanted to be a scientist,” he said. “And I thought, I can’t be a scientist unless I can replicate myself. I couldn’t replicate myself.” Doubting himself once again, he abandoned the study of personality, deciding he had no talent for it.



* * *




* Decades later, when Danny Kahneman was in his forties, he sat in for a day on a class at the University of California, Berkeley, taught by a psychologist named Eleanor Rosch. On that day, Rosch put a group of first-year graduate students through an exercise. She passed around a hat stuffed with slips of paper, on each slip a different occupation: zookeeper, airline pilot, carpenter, thief. The students were told to pick an occupation and then say what, if anything, popped to mind that foreshadowed their fate. Of course I wound up a zookeeper; as a kid I loved to cage our cat. The exercise was meant to illustrate the powerful instinct people have for finding causes for any effect, and also for creating narratives. “The whole group opens their papers at the same time,” recalled Rosch, “and within seconds someone laughs, and the laughter becomes general. And, yes, to their surprise, things have popped into their minds. Danny was the lone exception. “ ‘Nope,’ he said,” according to Rosch. “ ‘I could only have been two things. A psychologist or a rabbi.’”

? The word is German and means “shape” or “form” but, in a manner the Gestalt psychologists would enjoy, has itself tended to change shape, depending on the context in which it is used.





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