The Undoing Project: A Friendship that Changed the World

What Delta Air Lines should do, Amos suggested, was to change its decision-making environments. The mental mistakes that led pilots of planes bound for Miami to land boneheadedly in Fort Lauderdale were woven into human nature. People had trouble seeing when their minds were misleading them; on the other hand, they could sometimes see when other people’s minds were misleading them. But the cockpit culture of a commercial airliner did not encourage people to point out the mental errors of the man in charge. “Captains at the time would be complete autocratic jerks who insisted on running the show,” said Maher. The way to stop the captain from landing the plane in the wrong airport, Amos insisted, was to train others in the cockpit to question his judgment. “He changed the way we trained pilots,” said Maher. “We changed the culture in the cockpit and the autocratic jerk became no longer acceptable. Those mistakes haven’t happened since.”

By the 1980s, the ideas that Danny and Amos had hatched together were infiltrating places the two had never imagined them entering. Success created, among other things, a new market for critics. “We started this unknown field,” Amos told Miles Shore in the summer of 1983. “We were shaking trees and challenging the establishment. Now we are the establishment. And people are shaking our tree.” Those people tended to be self-serious intellectuals. Upon encountering Danny and Amos’s work, more than a few academics experienced the sensation that a person feels when a total stranger walks up and begins a sentence, “Don’t take this the wrong way, but. . . .” Whatever might follow, you just know that you’re not going to like it. The sound of laughter coming from the other side of Amos and Danny’s closed door hadn’t helped. It caused other intellectuals to wonder about their motives. “The glee is what created the suspicion,” said the philosopher Avishai Margalit. “They looked like people standing in front of a monkey cage, making faces at the monkeys. There was too much joy there. They said, ‘We’re monkeys, too.’ But no one believed them. The feeling was that the joy that they have is to trick people. And it stuck. It was a real problem for them.”

At a conference back in the early 1970s, Danny was introduced to a prominent philosopher named Max Black and tried to explain to the great man his work with Amos. “I’m not interested in the psychology of stupid people,” said Black, and walked away. Danny and Amos didn’t think of their work as the psychology of stupid people. Their very first experiments, dramatizing the weakness of people’s statistical intuitions, had been conducted on professional statisticians. For every simple problem that fooled undergraduates, they could come up with a more complicated version to fool professors. At least a few professors didn’t like the idea of that. “Give people a visual illusion and they say, ‘It’s only my eyes,’” said Princeton psychologist Eldar Shafir. “Give them a linguistic illusion. They’re fooled, but they say, ‘No big deal.’ Then you give them one of Amos and Danny’s examples and they say, ‘Now you’re insulting me.’”

The first to take their work personally were the psychologists whose work it had trumped. Amos’s former teacher Ward Edwards had written the original journal article in 1954 inviting psychologists to investigate the assumptions of economics. Still, he’d never imagined this—two Israelis walking into the room and making a mockery of the entire conversation. In late 1970, after reading early drafts of Amos and Danny’s papers on human judgment, Edwards wrote to complain. In what would be the first of many agitated letters, he adopted the tone of a wise and indulgent master speaking to his naive pupils. How could Amos and Danny possibly believe that there was anything to learn from putting silly questions to undergraduates? “I think your data collection methods are such that I don’t take seriously a single ‘experimental’ finding you present,” wrote Edwards. These students they had turned into their lab rats were “careless and inattentive. And if they are confused and inattentive, they are much less likely to behave more like competent intuitive statisticians.” For every supposed limitation of the human mind Danny and Amos had uncovered, Edwards had an explanation. The gambler’s fallacy, for instance. If people thought that a coin, after landing on heads five times in a row, was more likely, on the sixth toss, to land on tails, it wasn’t because they misunderstood randomness. It was because “people get bored doing the same thing all the time.”

Amos took the trouble to answer, almost politely, that first letter from his former professor. “It was certainly a pleasure to read your detailed comments on our papers and to see that, right or wrong, you have not lost any of your old fighting spirit,” he began, before describing his former professor as “not cogent.” “In particular,” Amos continued, “the objections you raised against our experimental method are simply unsupported. In essence, you engage in the practice of criticizing a procedural departure without showing how the departure might account for the results obtained. You do not present either contradictory data or a plausible alternative interpretation of our findings. Instead, you express a strong bias against our method of data collection and in favor of yours. This position is certainly understandable, yet it is hardly convincing.”

Edwards was not pleased, but he kept his anger to himself for a few years. “No one wanted to get in a fight with Amos,” said the psychologist Irv Biederman. “Not in public! I only once ever saw anyone ever do it. There was this philosopher. At a conference. He gets up to give his talk. He’s going to challenge heuristics. Amos was there. When he finished talking Amos got up to rebut. It was like an ISIS beheading. But with humor.” Edwards must have sensed, in any open conflict with Amos, the possibility of being on the painful end of an ISIS beheading, with humor. And yet Amos had championed the idea that man was a good intuitive statistician. He needed to say something.

In the late 1970s he finally found a principle on which to take a stand: The masses were not equipped to grasp Amos and Danny’s message. The subtleties were beyond them. People needed to be protected from misleading themselves into thinking that their minds were less trustworthy than they actually were. “I do not know whether you realize just how far that message has spread, or how devastating its effects have been,” Edwards wrote to Amos in September of 1979. “I attended the organizational meeting of the Society for Medical Decision Making one and a half weeks ago. I would estimate that every third paper mentioned your work in passing, mostly as justification for avoiding human intuition, judgment, decision making, and other intellectual processes.” Even sophisticated doctors were getting from Danny and Amos only the crude, simplified message that their minds could never be trusted. What would become of medicine? Of intellectual authority? Of experts?

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