In the fall of 1961, a few weeks after Amnon flew to the University of North Carolina, Amos left Jerusalem for the University of Michigan—where Ward Edwards had moved after being fired by Johns Hopkins, supposedly for not bothering to show up for the classes he was meant to be teaching. Neither Amnon nor Amos knew much about American universities. Amnon, who had just been assigned to North Carolina by a Fulbright scholarship committee, had to pull out his Atlas of the World to find it. Amos was able to read English, but he spoke so little that, when he told people where he planned to go, they assumed he was joking. “How will he even survive?” his friend Amia Lieblich asked herself. Neither Amnon nor Amos saw that they had any real choice. “There was nobody to teach us at Hebrew University,” Amnon said. “We had to leave.” Both Amnon and Amos assumed that the move was temporary: They would learn whatever there was to learn about this new field of decision making in the United States and then return to Israel and work together.
The earliest sightings of Amos Tversky in the United States are anomalies in the History of Amos. In their first week of classes, fellow students saw a silent, seemingly dutiful foreigner taking notes. They looked upon him with pity. “My first memory is of him being really, really quiet,” recalls fellow graduate student Paul Slovic. “Which is funny, because later on he really wasn’t quiet.” Seeing Amos writing from right to left, one student suggested that he might suffer from some mental disorder. (He was writing in Hebrew.) Stripped of the power of speech, Amos was jolted out of character. Long after the fact, Paul Slovic guessed that in his first few months away from home Amos merely had been biding his time. Until he knew exactly what he was saying, he wouldn’t say it.
By the middle of his first year Amos knew what he was saying—and from that moment the Amos stories came thick and fast. There was the time that Amos walked into an Ann Arbor diner and ordered a hamburger with relish. The waiter said they didn’t have relish. Okay, Amos said, I’ll have tomato. We don’t have tomato, either, said the waiter. “Can you tell me what else you don’t have?” asked Amos. There was the time Amos had arrived late for what everyone expected would be a grueling test, given by a dreaded professor of statistics, John Milholland. Amos slid into a desk just as the test was being passed out. The room was dead silent, the students anxious and tense. As Milholland reached his desk, Amos turned to the person seated next to him and said, “Forever and forever, farewell, John Milholland If we do meet again, why, we shall smile If not, why then, this parting was well made”: lines spoken by Brutus to Cassius in act 5, scene 1, of Julius Caesar. He aced the test.
Michigan required that all PhD students in psychology pass a proficiency test in two foreign languages. Weirdly, the university didn’t count Hebrew as a foreign language but accepted mathematics. Though entirely self-taught in mathematics, Amos chose math as one of his languages and passed the test. For his second language he picked French. The test was to translate three pages from a book in the language: The student chose the book, and the tester chose the pages to translate. Amos went to the library and dug out a French math textbook with nothing but equations in it. “It might have had the word donc in it,” said Amos’s roommate Mel Guyer. The University of Michigan declared Amos Tversky proficient in French.
Amos wanted to explore how people made decisions. To do this he required subjects who were both captive and poor enough that they would respond to the tiny financial incentives he could offer. He found them in the maximum security wing of the Jackson State Prison, near Ann Arbor. Amos offered the inmates—though only those with IQs over 100—different gambles, involving candy and cigarettes. Both functioned in the jail as currency, and everyone knew what they were worth—a pack of cigarettes and a sack of candy at the prison store each cost 30 cents, or about a week’s salary. The inmates could either take the gamble or sell the right to take the gamble to Amos—that is, receive a sure payout.
As it turned out, the Jackson Prison inmates choosing between gambles had a lot in common with Kenneth May’s students when they chose between spouses: After they had said they preferred A to B and B to C, they could be induced to prefer C to A. Even when you asked them up front whether they would ever chose C over A and they insisted they would never do such a thing, they did it. Some thought Amos must be playing a trick on the inmates, but he wasn’t. “He didn’t trick the prisoners into violating transitivity,” says Michigan professor Rich Gonzalez. “He used a process much like the old saying about the frog in the pot of boiling water. As the temperature increases slowly, the frog can’t detect it. Obviously the frog can detect 90 degrees versus 200 degrees, but not increments of a single degree. In some of our biological systems we are equipped to detect big differences; in others, small ones—say, a tickle versus a poke. If people can’t detect small differences, Amos figured, they might violate transitivity.”
Clearly people had trouble detecting small differences. Prison inmates and Harvard students, on whom Amos also ran tests. He wrote a paper about his experiments in which he showed how one might even predict when people would be intransitive. And yet . . . he didn’t read much into this. Rather than draw some grand conclusions about the inadequacy of existing assumptions about human rationality, he pulled himself up short. “Is this behavior irrational?” he wrote. “We tend to doubt it. . . . When faced with complex multidimensional alternatives, such as job offers, gambles or [political] candidates, it is extremely difficult to utilize properly all the available information.” It wasn’t that people actually preferred A to B and B to C and then turned around and preferred C to A. It was that it was sometimes very hard to understand the differences. Amos didn’t think that the real world was as likely to fool people into contradicting themselves as were the experiments he had designed.
The man whose work had pulled Amos to Michigan, Ward Edwards, turned out to be more appealing to Amos on the page than in the flesh. After Johns Hopkins fired him, Edwards found a place in Michigan, but his position was insecure, and so was he. When students arrived to work with him, he gave each of them a pompous little lecture—they called it the “key” lecture. Edwards would hold up the key to the door of the small house that served as his lab and tell the student what an honor it was for him to be entrusted with the key and, by extension, an association with Edwards. “You got this key along with the speech,” says Paul Slovic. “The meaning of the key, the symbol of the key—it was all a little weird. Usually someone just gives you a key and tells you to make sure you lock the door when you leave.”