Tversky: Decisions Under Fire - The Undoing Project: A Friendship That Changed Our Minds

Okay, so, like, this is about this guy, Amos Tversky, right? And, uh, the chapter's called "The Insider."

So, it starts with this other dude, Amnon, Amnon Rapoport. When he was, like, 18, the Israeli army, you know, they figured he had leadership potential. So they made him a tank commander. He's like, "I didn't even know there WAS a tank division!" So one night, they sent him to, like, roll into Jordan to, uh, retaliate for some Israeli civilians that were killed. And, you know, in these raids, you never know what decisions you're gonna have to make, like, on the fly.

So Amnon, his first decision that night was to NOT fire. He was supposed to shell the second floor of a Jordanian police station, but he was worried about hitting his own guys. And, uh, you know, he heard the radio chatter from the ground. And he said it kinda, like, woke him up. It wasn’t just a game anymore. It was life or death. And the paratroopers, they were taking heavy casualties, but the calls from the battlefield, he said they were, like, so calm, almost detached. He said, “No panic at all, just calm, almost emotionless.” These Jews, he thought, they’re turning into Spartans or something.

Then, like, two weeks later, Amnon's driving his tank into Egypt, kicking off the military invasion. There was so much smoke and fire, dodging Egyptian fire and friendly fire. One time, a MiG-15, an Egyptian fighter jet, came right at his tank. He was sticking his head out the turret, looking around, and he had to yell at the driver to swerve to avoid getting his head chopped off. Later, he saw some Egyptian soldiers surrendering, begging for water and protection from the Bedouins. One day he was trying to kill these guys, the next he felt sorry for them. It’s just… wild.

After the war, Amnon just wanted to get away from everything. He said, "Two years in the tanks turned me into kind of a wild man." So, he goes and gets a job in a copper mine in the desert. Turns out he's good at math, so he becomes the mine's librarian, basically. This was, like, a pretty basic operation, no bathrooms, no toilet paper. So he’s, uh… you know, doing his business outside, and he sees a newspaper. And it says that Hebrew University is starting a psychology program. He was like, 20. He'd only heard of Freud and Jung. There weren't many psych books in Hebrew, but something about it just grabbed him.

So he applies. And it was super competitive, way more than other programs. He goes to this old monastery that the university was using, and there were all these crazy tests. One of them was designed by Daniel Kahneman, this guy who wrote an essay in a made-up language and asked people to analyze the grammar. The line was, like, down the street. Only twenty spots, but hundreds of people were trying to get in. It turns out, those twenty were, like, brilliant. Nineteen of them got PhDs.

And that’s where he meets Amos. Amos Tversky. He’s this small, pale guy, with a baby face, looks like he’s, like, fifteen, but he's wearing these rubber boots, a crisp uniform, and a red paratrooper beret. Total, like, mini-Spartan warrior. Amnon said, "I knew right away he was smarter than me."

So, Amos. To Israelis, he was this, like, amazing, different person, but also, like, the epitome of what an Israeli should be. His parents left Russia in the '20s to get away from the anti-Semitism and became pioneers in the Zionist movement. His mom, Ginnya, was super into politics. She got elected to the first Israeli parliament and stayed there for five terms. She was always traveling, helping refugees. His dad, Joseph, was a veterinarian. He wasn't religious, loved Russian literature. Amos said he became a vet because "animals suffer more than humans but complain less." He was serious, but he would tell Amos stories about his life, about the mystery of existence.

Amos always said that some people have interesting things happen to them because they’re good at turning ordinary things into interesting stories. And he was a master storyteller. He had a bit of a lisp, and he was super pale, you could almost see the veins under his skin. His blue eyes were always darting around, like he was trying to catch every idea that came his way.

He always seemed to be moving, even when he was talking. He wasn't really athletic, small guy, but he was super agile. He could run around on mountains, just like a mountain man. He had this trick, where he'd climb up high, on a rock or a tank, and then dive off, face down, parallel to the ground. He'd always catch himself at the last second. He loved the feeling of falling, looking down at the earth.

He was brave, or at least he wanted to seem brave. When he was, like, twelve, his family moved to Haifa, and he went to the swimming pool. There was a ten-meter diving board, and the other kids were daring him to jump. He’d never learned to swim. He grabs this older kid and tells him, "I'll jump, but you have to pull me out of the water." And he just goes for it, jumps off the ten-meter board, and the kid pulls him out before he drowns.

In high school, Amos had to choose between arts and sciences. The country wanted boys to study science. Amos was super talented at science. But he chose humanities. He wanted something new. He could teach himself math, but humanities gave him something different. He loved this teacher, Baruch Kurzweil. He wrote him poems, even said he wanted to be a poet or a literary critic.

Privately, Amos was close with this girl named Dahlia Ravikovitch. She had a rough life, her dad died. Amos, the popular kid, was friends with her. It was weird. He liked being outside, she smoked by the window during gym class. Later, she became a famous poet. People were like, "Oh, well, they were both geniuses." Amos wanted to study with Kurzweil, but it didn’t happen. Amos was always the positive one. Dahlia and Kurzweil, they both tried to commit suicide.

Like most kids in Haifa, Amos joined this left-wing youth organization called "Nahal." It was about sending young Zionists to kibbutzim to farm and defend them. In his last year of high school, General Moshe Dayan came to Haifa and gave a speech. He asked how many people joined Nahal, a bunch of people raised their hands. Dayan said, "You're all traitors. We don't need you to grow tomatoes and cucumbers, we need you to fight." So the next year, Israel said that every youth organization had to send 12 out of every hundred to the paratroopers. Amos volunteered right away. He was too light, so he drank a bunch of water to make weight.

At paratrooper training, they were made into warriors, killing machines. Cowardice wasn't an option. They had to jump from a 5.5-meter tower. Then they had to get on this old wooden plane from World War II. They had to jump out, or they'd get pushed.

Most guys were scared at first. Amos's group had this one guy who wouldn't jump, and it was a mark on him for life. But Amos never hesitated. One of the guys said, "He was always the first one to jump out of the plane." He jumped, like, fifty times. One time, he jumped into a beehive and got stung so bad he passed out. In '61, when he flew to the U.S. for grad school, he couldn't believe how the plane landed. He was, like, "I've never landed like that before."

He became a platoon leader pretty quickly. He was in charge. He said, "I can't believe how fast I've adapted to this new life."

There were some things he didn't write about. He was ordered to participate in retaliatory raids. He lost friends, he saved friends. He said, "I saved a buddy in a 'blood for blood' mission, and I was praised for it, but I don't think I'm a hero. I just wanted my friends to get home safely."

One time, this sadistic officer wouldn't give the soldiers water to see how long they could last without it. One of Amos's guys died from dehydration. Amos testified against the officer. One night, Amos’s men beat another abusive officer using blankets. Amos didn’t participate, but during the investigation, he helped them avoid prosecution. “Answer their questions with a lot of irrelevant details until they get bored and stop asking,” he told them.

By the end of '56, Amos was, like, a decorated war hero. During an exercise, one of his men was supposed to blow up a barbed wire fence with dynamite. He pulled the fuse but passed out on top of the dynamite. The officers told everyone to stay back. Amos ignored them. He grabbed the guy, carried him ten meters, threw him to the ground, and jumped on top of him. Shrapnel stayed in Amos’s body forever. Moshe Dayan gave him the medal and said, "You did something stupid and brave, you might not be so lucky next time."

Sometimes it seemed like Amos cared more about looking like a man than being safe. His friend Yuri Shamir said, "I think maybe because he was small and pale, he wanted to compensate." But in a way, he forced himself to be brave, and it became a habit. By the time his military service was ending, he felt like a different person.

He rarely talked about his military life, except for the funny or weird things. Like, in the Sinai War, his unit captured a bunch of Egyptian camels. Amos had never ridden a camel, he got sick after 15 minutes and had to ride in an open truck for six days. Then he won the camel race on the way home.

Or his soldiers. They wouldn't wear helmets in combat, they said it was too hot and if they got shot, at least the bullet would have their name on it. (Amos said, "What if all the bullets are 'no name'?")

He would start his stories with little details. Samuel Shattath said, "Whenever you met him, he would ask, 'Did I tell you this story?' But the story had nothing to do with him. For example, 'You know, when you go to a meeting in an Israeli university, everyone interrupts each other, because they're afraid someone else will say their idea first. And at faculty meetings in American universities, everyone is quiet, because they assume someone else wants to say the same thing...'" Then he'd go on about the differences between Americans and Israelis.

People knew his stories were just a way for him to entertain himself. He liked to tell stories that poke fun at people he thought were full of themselves. He met this American economist who was calling everyone an idiot, and Amos told him, "All your economic models rely on intelligent and rational people, but you're surrounded by morons."

People said he was just incredibly smart. Avishai Margalit said, "He always got to the core of any subject. It was an astonishing ability." Yive Biederman said, "He didn't look impressive. If there were 30 people in a room, he'd be the last one you'd notice. But as soon as he opened his mouth, everyone knew he was brilliant." Dick Nisbett made up this intelligence test: "The faster you realize that Amos is smarter than you, the smarter you are."

But people also talked about his lifestyle. He was a night owl, slept until sunset. He ate pickles for breakfast and eggs for dinner. He tried to cut out anything he thought was a waste of time, like shaving and brushing his teeth in the rearview mirror on the way to work. His daughter, Dona, said, "He never knew what time it was, but it didn't matter. He lived in his own world, you just happened to meet him there." He would quote Muriel Spark: "For those who like that sort of thing, that is the sort of thing they like."

He would just do things. If he wanted to run, he'd just... run. No stretching, no changing, just ripped off his pants and took off running. His friend Avishai Margalit said, "Amos thought people sacrificed too much to avoid minor embarrassments."

He also had this amazing ability to focus on what was important to him. His friend Varda Lieberman said he had a desk full of unopened mail. It was organized by date, and it was all invitations, honorary degrees, interview requests, bills. He'd open the ones he wanted and leave the rest. When it got too full, he'd just throw the whole pile in the trash. He liked to say, "The beauty of urgent things is that if you leave them alone long enough, they stop being urgent."

He was just... pure. His likes and dislikes were clear. His kids remembered going to the movies with him. They'd drive, and then he'd come back and watch Hill Street Blues (his favorite show) or NBA games. He'd say, "They already took my money, are they going to take my time too?" If he was at a party he didn’t like, he'd just disappear. His daughter Dona said, "He would turn himself into the background. He seemed to have this superpower."

He offended some people, of course. His blue eyes made some people uncomfortable. He was always looking around, people thought he wasn't listening, but he was. Avishai Margalit said, "For him, the biggest problem was people who didn't know what they didn't know. If he found you boring, he would cut you off."

He didn't worry about whether people liked him. Samuel Sattath said, "His greatest desire was to charm people, which is kind of strange for someone so smart." Yeshayahu Kolodny said, "He wanted people to admire him, to love him. And if he liked you, it was easy for him to be genuine. His friends would get jealous. They would ask themselves: I know why I like him, but why does he like me?"

Amnon Rapoport, he had no shortage of admirers, because he was a war hero. He was a good-looking guy. He said, "I knew his brilliance was a huge attraction for me, but I didn't know what I had that attracted him, maybe because everyone thought I was handsome." They became inseparable. They were desk mates in class, neighbors in their apartments. They were well-known. Amnon said, "I guess some people thought we were gay or something."

While Amos was trying to decide his career path, Amnon was at the peak of his own career. Amos chose philosophy and psychology. After two years of philosophy, he announced that there was nothing left to find there. "We can't do anything with philosophy," he said. "Plato has already solved most of the problems. There are too many wise sages, and too few problems, and the few that are left are unsolvable." He felt that philosophy didn't follow scientific rules. Psych at least tried to look like a science, with data and testing.

For his Israeli friends, Amos's interest in psych made sense. They were always talking about "why people do things" and "why people think that way." Avishai Margalit said, "He never talked to us about art, only about people. It was a constant topic, a constant mystery." But some people didn't understand why someone as clear-headed as Amos would go into such a murky field.

Amos rarely talked about it. When he did, he made it sound like it was just a random choice. He was sitting with this psychiatrist, Miles Shore, and Shore asked him how he became a psychologist. Amos said, "It's hard to say how people choose their paths in life. Many of our big choices are actually random, but the small, unimportant choices can reflect who we really are. What field we enter might depend on what teacher we happen to have in high school, who we marry might depend on who happens to be around at the right time. The small choices, on the other hand, are consistent. Being a psychologist doesn't say much, being what kind of psychologist says a lot."

And what kind of psychologist was he? Well, Amos wasn’t really interested in most of psychology. He said most of it was garbage. He was incredibly disinterested in his assignments. Emiah Lieblich saw how nonchalant Amos was when the professor assigned him an IQ test with a 5-year-old child. "On the eve of the deadline, Amos found Amnon and said, 'Amnon, lie down on the couch. I'm going to ask you some questions, you have to imagine yourself as a 5-year-old child.' That's how he did it!" In class, Amos was the only student who didn't take notes. Before the exams, he would look at Amnon's notes. "He only needed to look at them once to understand them better than me," Amnon said. "Also incredibly, if he met a physicist on the street, he could talk to him for half an hour, even though he didn't know anything about physics. At first I thought he only knew the basics – like a party trick, but I was wrong. It wasn’t a trick.”

Too many of the professors seemed to be teaching by feel, which wasn’t beneficial to the students.

In 1959, when they were in their second year at Hebrew University, Amnon came across an article called "Decision Theory" by Ward Edwards, a professor at Johns Hopkins University. It said that many sociologists and not many psychologists had tried to explain the root of individual behavior. A number of economists and a few psychologists had used a lot of theory and little empirical data to discuss individual decision-making.

Edwards wasn’t setting himself or his research against economics. He was simply saying that psychologists could test the assumptions economists put forward. Economists assumed that people were “rational.” What did that mean? At the very least it meant people knew what they wanted. Faced with a series of options, people were able to rank them in terms of preference. But when people ranked their preferences, did they break the rules?

When Amnon showed Ward Edwards's article about decision theory to Amos, Amos was excited. "Amos always had a better sense than others," Amnon said. "This time he smelled the prey."

In the fall of 1961, a few weeks after Amnon flew to the University of North Carolina, Amos left Jerusalem and went to the University of Michigan. Neither Amnon nor Amos were very familiar with American universities. Amnon was relying on a world atlas to find the place. And Amos, although he could read English, basically couldn't speak it, so people thought he was joking when they heard he was going to America. But Amnon and Amos both knew that studying abroad was the only path. "There was no one to teach us at Hebrew University," Amnon said. "Leaving was the only option." The two also knew that their departure was only temporary: they would immerse themselves in the new field of decision-making in the United States, learn whatever they could, then return to Israel and work together.

When Amos first came to the United States, he was a taciturn, deferential foreign student who quietly took notes. He gave the impression he was having emotional difficulties. When Amos put his language skills aside, his personality changed. Paul Slovic says that Amos was saving his strength during those first few months in the US, before he was confident in what he had to say.

After about six months, Amos became more confident. He was once in the cafeteria at the University of Michigan and asked for a hamburger with sauce. The waiter said there was no sauce. Amos said, OK, add some tomatoes. The waiter said, “We also don’t have tomatoes.” “Can you tell me what you don’t have?” Amos asked. On another occasion, Amos was late for a test. Just as the test papers were being passed out, Amos slipped into his seat. There was total silence in the classroom. When Millholand reached Amos’s seat, Amos suddenly turned and said, “Farewell, John Millholand / If ever thou wilt behold me after, / Thou shalt but smile, as one that tells a tale / If we do meet again, why, we shall smile; / If not, why then this parting was well made.” As a result, he passed the exam with a high score.

The University of Michigan required all doctoral students in psychology to pass a proficiency test in two foreign languages. Inexplicably, the university didn’t recognize Hebrew as a foreign language. It did recognize mathematics. Despite being entirely self-taught in math, Amos decided to use it for the test and passed. He chose French as his second language. The exam format was to translate three pages of French text, and the rule was that candidates could choose the book, but the examiner would specify the page number. Amos rummaged through the library and found a math book written in French. The University of Michigan approved Amos’s French and announced that he had passed the test.

Amos wanted to explore how humans made decisions, so he chose prisoners as his research subjects and made sure to choose prisoners who were in extreme financial straits to ensure that they would actively cooperate with the small material rewards he offered. Amos only selected inmates with an IQ above 100 and offered them different rewards, including candy and cigarettes.

The prisoners at Jackson State Prison behaved a lot like Kenneth May’s students doing marriage preference questions: even after clearly stating that they preferred A over B and B over C, it was still possible for them to choose C over A. And some people thought Amos had done something to trick the prisoners, but obviously he hadn’t. "He didn't do anything by hand to get these prisoners to break the rules," said Richard Gonzalez, a professor at the University of Michigan. "He said that when people don't notice those small differences, the law of 'transitivity' is broken."

Obviously, people always had a hard time detecting small differences. Prison inmates are like this, and so are talented students at Harvard. The latter had also been the subject of Amos’s research. In one study, Amos elaborated on how to predict people’s behavior when they broke the law of “transitivity.” Even before his theory could be fully understood, he was challenging what was known.

What drew Amos to the University of Michigan was Ward Edwards, but in reality it was his writing that was the most impressive thing about him. After being fired from Johns Hopkins University, Edwards found a teaching position at the University of Michigan. What students learned from him was that if you got the honor of working with him, it would be a great gift. And whenever researchers came to visit, Edwards would hold parties in his home, but guests would have to pay for their own drinks. When there was a research task, he would assign it to Amos, but not provide funding, forcing Amos to resist. Edwards insisted that part of the work Amos was doing in his lab was Edwards’s, and therefore every paper Amos wrote had to have Edwards’s name on it.

As it is today, the University of Michigan had one of the largest psychology programs in the world. The ideas of Clyde Coombs attracted Amos among the other scholars studying decision problems. Coombs had been hired by General Mills to test consumer attitudes toward its products. But how could the degree of people’s preference for a certain cereal be measured? What scale was used to test it? In order to predict their behavior, their preferences had to be measured, but how?

To solve these problems, Coombs first divided the decisions into groups, each of which contained two options as comparison items. A person might sketch out an ideal partner in their mind, or some qualities they thought would be best for the other person to have. And to prove what he said was true, or perhaps to make it sound more plausible, Coombs used a cup of tea to interpret his point of view. How does a person decide how much sugar to put in a cup of tea?

As an example of choosing a partner, everyone might have a vague outline of an ideal partner in their mind, maybe some qualities that were considered essential. From there, he would choose the one closest to the ideal partner from among the potential candidates around him. To understand this selection process, you obviously need to know how much weight they give to different traits.

Like Coombs, Amos was fascinated by questions like how to measure things that couldn’t be observed. But at the same time, he also found that measuring people’s preferences led to another problem. If you accepted the basic assumption that people were making judgments by comparing images in their minds with real objects, then you needed to know how people made these judgments. When we judge whether two objects are similar, how does the mind work?

Psychology’s main theory about how people make similarity judgments is that similarity judgments are based on physical distance. When you compare two objects, you look for how "close" they are to each other. According to psychological theory, two items, two people, two ideas, two emotions exist in our minds as two points separated by a certain distance. Amos didn’t understand this. He had read an article by Eleanor Rosch that studied how people categorized things. What makes a table a table? What makes one color different from another? In the process, Rosch asked subjects to compare colors and judge the degree of similarity between the two colors.

The subjects made some strange judgments. For example, they thought fuchsia was similar to red, but red wasn’t similar to fuchsia. Amos found the contradiction in the answers and began to search more deeply. People think that Tel Aviv is similar to New York, but New York is not similar to Tel Aviv. People think that the number 103 is close to 100, but 100 isn’t close to 103. People think toy trains are like real trains, but they don’t think real trains are like toy trains.

When people compare two objects—two people, two places, two numbers, two ideas—they don’t pay much attention to symmetry. In Amos’s view. This phenomenon proved that all the theories that scholars had conceived to explain how people made similarity judgments were untenable.

Suppose that in a certain mind map, New York and Tel Aviv are separated by a certain distance, and Tel Aviv and New York are separated by the same distance. But you only need to ask others to know that the two are not similar.

Amos proposed his own theory, which he called "similarity feature" (the research paper with this title wasn’t published until 1977, but the concept had taken shape 10 years earlier when he was still a graduate student). Amos believed that when people compared two objects and judged the similarity between them, they were actually listing their characteristics. People would extract some of the surface features they had in common when comparing two objects: the more common features, the greater the similarity between the two. Not all objects have the same number of surface features. For example, New York has more surface features than Tel Aviv.

Before Richard Gonzalez went to Stanford University to pursue his doctorate in the 1980s, he had seen the "similarity feature" theory many times in books. He introduced himself and asked a question he thought was extremely sharp: "What do you do if one of the objects of comparison is a three-legged dog?" Two three-legged dogs must be more similar than a three-legged dog and a four-legged dog. However, the three-legged dog and the four-legged dog have just as many surface features.

What was even more revealing was what happened when three cups of coffee with sugar were placed in front of the men.

Amos’s theory of similarity judgment stimulated a variety of interesting insights. If the human brain is counting the characteristics of each object it notices when comparing two objects, then it can also judge two objects that have higher similarity and higher differences.

The process of making decisions is actually the process of making similarity judgments between real objects in the real world and imagined objects in the ideal world. This is undoubtedly an interesting point of view. People actually complete the judgment by listing the surface features of the object.

Amos’s theory is not the icing on the cake in the study of how people make similarity judgments, but a unique leader. Richard Gonzalez said: "His achievements in scientific research are not gradual, but leap-forward. He saw a research field, noticed a generally accepted proposition in the field, and then overturned the proposition with a wave of his hand. He felt that he was someone who was singing against the scientific community. The word he said most often was 'negation'. It turns out that this attitude is a sharp blade for doing scientific research." Amos was doing research in the spirit of "solving the mistakes others have made." As we will see, there are quite a few of these mistakes.