The Undoing Project: A Friendship that Changed the World(21)

What he did was teach the army interviewers—young women, mainly—how to put a list of questions to each recruit to minimize the halo effect. He told them to pose very specific questions, designed to determine not how a person thought of himself but how the person had actually behaved. The questions were not just fact-seeking but designed to disguise the facts being sought. And at the end of each section, before moving on to the next, the interviewer was to assign a rating from 1 to 5 that corresponded with choices ranging from “never displays this kind of behavior” to “always displays this kind of behavior.” So, for example, when evaluating a recruit’s sociability, they’d give a 5 to a person who “forms close social relationships and identifies completely with the whole group” and a 1 to “a person who was “completely isolated.” Even Danny could see that there were all kinds of problems with his methods, but he didn’t have the time to worry too much about them. For instance, he briefly agonized over how to define a 3—was it someone who was extremely sociable on occasion, or someone who was moderately sociable all the time? Both, he basically decided. The big thing was that the judge was to keep her private opinions to herself. The question was not “What do I think of him?” but “What has he done?” The judgment of who went where in the Israeli army was to be made by Danny’s algorithm. “The interviewers hated it,” he recalled. “I had a mutiny on my hands. I still remember one of them saying, ‘You’re turning us into robots.’ They had a sense that they could tell [a person’s character]. And I was robbing them of that. And they really didn’t like it.”

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.”