Amos, when he talked about it, which he usually didn’t, made it seem as if it had started as a whim. When he was in his midforties and many of the brightest young minds in the field wanted to study with him, he sat down with a professor of psychiatry at Harvard named Miles Shore. Shore asked him how he had become a psychologist. “It’s hard to know how people select a course in life,” Amos said. “The big choices we make are practically random. The small choices probably tell us more about who we are. Which field we go into may depend on which high school teacher we happen to meet. Who we marry may depend on who happens to be around at the right time of life. On the other hand, the small decisions are very systematic. That I became a psychologist is probably not very revealing. What kind of psychologist I am may reflect deep traits.”
What kind of psychologist would he be? In most of psychology Amos found little to interest him. After taking classes in child psychology and clinical psychology and social psychology, he concluded that the vast majority of his chosen field was safely ignorable. To his assigned work he paid shockingly little attention. His classmate Amia Lieblich witnessed Amos’s insouciance after he’d been assigned by a professor to administer an intelligence test to a five-year-old child. “The night before the work was due, Amos turned to Amnon and said, ‘Amnon, lie down on the couch. I am going to ask you some questions. Pretend you are five years old.’ And he got away with it!” Amos was the only student who never took notes in class. When the time came to study for some test, Amos would simply ask to see Amnon’s notes. “He would read my notes once and know the material better than I did,” said Amnon. “It was the same way he could meet a physicist in the street, talk to him for thirty minutes, without knowing anything about physics, and then tell the physicist something about physics the physicist didn’t know. I first thought he was a superb superficial person—that it was a party trick. And that was a mistake. Because it wasn’t a trick.”
It didn’t help that so many of the professors seemed to be flying by the seat of their pants. The guy who had come from Scotland to teach the history of psychology was sent back when it was discovered he had fabricated his PhD. A guy they brought in to teach a class on personality testing—a Polish Jew who had survived the Holocaust by hiding in the woods—fled the classroom in tears under questioning from Amos and Amnon. “We basically had to teach psychology to ourselves,” recalled Amnon. Amos compared clinical psychology—everywhere on the rise, and the field of greatest interest to their fellow students, most of whom hoped to become therapists—to medicine. If you went to a doctor in the seventeenth century, you were worse off for having gone. By the end of the nineteenth century, going to the doctor was a break-even proposition: You were as likely to come away from the visit better off as you were to be worse off. Amos argued that clinical psychology was like medicine in the seventeenth century, and he had lots of evidence to support his case.
One day during their second year at Hebrew University, in 1959, Amnon came across a paper called “The Theory of Decision Making,” by a psychology professor at Johns Hopkins named Ward Edwards. “Many social scientists other than psychologists try to account for the behavior of individuals,” it opened. “Economists and a few psychologists have produced a large body of theory and a few experiments that deal with individual decision making. The kind of decision making with which this body of theory deals is as follows: given two states, A and B, into either one of which an individual may put himself, the individual chooses A in preference to B (or vice versa). For instance, a child standing in front of a candy counter may be considering two states. In state A the child has $0.25 and no candy. In state B the child has $0.15 and a tencent candy bar. The economic theory of decision making is a theory about how to predict such decisions.” Edwards went on to lay out a problem: Economic theory, the design of markets, public policy making, and a lot more depended on theories about how people made decisions. But psychologists—the people most likely to test these theories and determine how people actually made decisions—hadn’t paid much attention to the subject.
Edwards wasn’t setting himself, or his field, in opposition to economics. He was merely proposing that psychologists be invited, or perhaps invite themselves, to test both the assumptions and the predictions made by economists. Economists assumed that people were “rational.” What did they mean by that? At the very least, they meant that people could figure out what they wanted. Given some array of choices, they could order them logically, according to their tastes. For example, if they were handed a menu that listed three hot drinks, and they said that at some given moment they preferred coffee to tea, and tea to hot chocolate, they should logically prefer coffee to hot chocolate. If they preferred A to B and B to C, they should prefer A to C. In the academic jargon, they were “transitive.” If people couldn’t order their preferences logically, how would any market ever function properly? If people preferred coffee to tea and tea to hot chocolate—but then turned around and chose hot chocolate over coffee—they’d never finish choosing. They’d be willing, in principle, to pay to switch from hot chocolate to tea and also to switch from tea to coffee—and then pay again to switch from coffee to hot chocolate. They’d never settle on a drink but instead would be stuck in this mad infinite loop in which they kept paying to upgrade from the drink they had to a drink they liked better.
Here was one of the predictions that economists made that Edwards thought psychologists might test: Are actual human beings transitive? If at any given moment they preferred coffee to tea and tea to hot chocolate, did they prefer coffee to hot chocolate? A few people had recently looked into the matter, Edwards noted, among them a mathematician named Kenneth May. Writing in a leading economics journal, Econometrica, May described how he had tested just how logical his own students were when asked to choose a spouse. He’d presented students with three potential mates, ranked by three qualities: how good-looking they were, how smart they were, and how much money they had. None of the three potential mates was extreme in any one way: No one was so poor, dumb, or hard on the eye as to be repugnant. Each had relative strengths and weaknesses: Each ranked highest in one category, second highest in another, and last in the third. May’s students, in making their choices, never faced all three potential marriage partners at the same time. Instead they were shown pairs, and asked to choose between them. For example, they might be asked to choose between the potential mate who was the brightest, second-best-looking, but poorest, and the potential mate who was the richest, the second-brightest, but the least good-looking.
Once the dust had settled in this flurry of decision making, more than a quarter of the students had revealed themselves as irrational, at least from the point of view of economic theory. They’d decided that they would rather marry Jim than Bill, and Bill than Harry—but then also said that they would rather marry Harry than Jim. If people could buy and sell spouses like hot drinks, some large number of them would never settle on one spouse but would instead keep paying to upgrade. Why? May didn’t offer a full explanation, but he suggested the beginning of one: Because Jim and Bill and Harry each had relative strengths and weaknesses, they were hard to compare. “It is just these non-comparable cases that are of interest,” wrote May. “Comparison of alternatives in which one is superior to the other in every respect makes for a simple but rather trivial theory.”
Amnon showed Ward Edwards’s paper on decision making to Amos, and Amos grew very excited. “Amos will smell gold before anyone else will smell it,” said Amnon. “And he smelled gold.”
* * *