The Undoing Project: A Friendship That Changed Our Minds

by Michael Lewis

After seeing the diabolically clever data-based approach taken by the North Carolina legislature in writing laws to make it more difficult for African Americans to vote, the comedian John Oliver congratulated the legislators for having “Money-balled racism.”

They gathered information on the players’ lives and looked for patterns in it. Did it help a player to have two parents in his life? Was it an advantage to be left-handed?

“Almost everything we looked at was nonpredictive,” says Morey.

Rebounds per minute were useful in predicting the future success of big guys. Steals per minute told you something about the small ones.

You needed experts. The limits of any model invited human judgment back into the decision-making process—whether it helped or not.

The label they’d stuck on him clearly had affected how they valued him: names mattered. “I made a new rule right then,” said Morey. “I banned nicknames.”

The human mind was just bad at seeing things it did not expect to see, and a bit too eager to see what it expected to see.

Morey’s solution was to forbid all intraracial comparison. “We’ve said, ‘If you want to compare this player to another player, you can only do it if they are a different race.’”

A funny thing happened when you forced people to cross racial lines in their minds: They ceased to see analogies.

“I still remember where I was—the street in Jerusalem. I remember thinking that I could imagine there was a God, but not one who cared whether or not I masturbate. I reached the conclusion that there was no God. That was the end of my religious life.”

The central question posed by Gestalt psychologists was the question the behaviorists had elected to ignore: How does the brain create meaning?

How does it turn the fragments collected by the senses into a coherent picture of reality?

“I’ve always felt ideas were a dime a dozen,” he said. “If you had one that didn’t work out, you should not fight too hard to save it, just go find another.”

“When someone says something, don’t ask yourself if it is true. Ask what it might be true of.”

his ability to find the phenomenon and then explain it in a way that applies to other situations,”

The sooner you figure out that Amos is smarter than you are, the smarter you are.

“Comparison of alternatives in which one is superior to the other in every respect makes for a simple but rather trivial theory.”

the university didn’t count Hebrew as a foreign language but accepted mathematics.

If people can’t detect small differences, Amos figured, they might violate transitivity.”

Amos liked to say that stinginess was contagious and so was generosity, and since behaving generously made you happier than behaving stingily, you should avoid stingy people and spend your time only with generous ones.

The reigning theories in psychology of how people made judgments about similarity all had one thing in common: They were based on physical distance. When you compare two things, you are asking how closely they resemble each other. Two objects, two people, two ideas, two emotions: In psychological theory they existed in the mind as they would on a map, or on a grid, or in some other physical space, as points with some fixed relationship to each other.

magenta was similar to red, but that red wasn’t similar to magenta.

He asked people if they thought North Korea was like Red China. They said yes. He asked them if Red China was like North Korea—and they said no.

Tel Aviv was like New York but that New York was n...

the number 103 was sort of like the number 100, but that 1...

a toy train was a lot like a real train but that a real train was ...

a son resembled his father, but if you asked them if the father resembled his son, they ju...

“We say ‘Turks fight like tigers’ and not ‘tigers fight like Turks.’ Since the tiger is renowned for its fighting spirit, it is used as the referent rather than the subject of the simile. The poet writes ‘my love is as deep as the ocean,’ not ‘the ocean is as deep as my love,’ because the ocean epitomizes depth.”

“What Amos worked out was that whatever is going on is not a distance,” says Gonzalez.

Not all objects have the same number of noticeable features: New York City had more of them than Tel Aviv, for instance.

‘The absence of a feature is a feature.’”

“Similarity increases with the addition of common features and/or deletion of distinctive features.”

When people picked coffee over tea, and tea over hot chocolate, and then turned around and picked hot chocolate over coffee—they weren’t comparing two drinks in some holistic manner. Hot drinks didn’t exist as points on some mental map at fixed distances from some ideal. They were collections of features. Those features might become more or less noticeable; their prominence in the mind depended on the context in which they were perceived. And the choice created its own context: Different features might assume greater prominence in the mind when the coffee was being compared to tea (caffeine) than when it was being compared to hot chocolate (sugar).

By changing the context in which two things are compared, you submerge certain features and force others to the surface.

“It is generally assumed that classifications are determined by similarities among the objects,” wrote Amos, before offering up an opposing view: that “the similarity of objects is modified by the manner in which they are classified.

similarity has two faces: causal and derivative. It serves as a basis for the classification of objects, but is also influen...

Things are grouped together for a reason, but, once they are grouped, their grouping causes them to seem more like each other than they otherwise would. That is, the mere act of classification reinforces stereotypes. If you want to weaken some stereotype, eliminate the classification.

The standard joke was: Someone runs out of their burning house to ask a friend on the street if they know someone in the Fire Department.”

One student had so insulted a visiting American intellectual by interrupting his talk with derisive comments that university officials demanded he seek out the American and apologize. “I’m sorry if I have hurt your feelings,” the student had said to the visiting dignitary, “but, you see, the talk was so bad!”

The Israeli government arranged quietly for the public parks to be consecrated, to allow them to be used as mass graves.

The entire country mobilized. Private cars took over the bus routes—as all the buses had been taken by the army. Schoolchildren delivered the milk and the mail.

“I grew up in the Vietnam War and I hadn’t known anyone who had gone to Vietnam, much less died there,” said Barbara. “I knew four people who were killed in the Six-Day War—and I’d only been there six months.”

“He wasn’t just teaching statistics. He was teaching: what is the meaning of all this?”

Then he told them about the Purkinje effect—named for the Czech physiologist who had first described it, in the early nineteenth century. Purkinje had noticed that colors that appeared brightest to the human eye in broad daylight appeared the darkest at dusk. And so, for instance, what the rabbis saw as vividly red in the morning might appear, in contrast to other colors, almost colorless in the evening.

“How do you understand memory?” he asked. “You don’t study memory. You study forgetting.”

“Reforms always create winners and losers,” Danny explained, “and the losers will always fight harder than the winners.”

The psychologist Kurt Lewin had suggested persuasively that, rather than selling people on some change, you were better off identifying the reasons for their resistance, and addressing those.

Danny thought, This is what happens when people become attached to a theory. They fit the evidence to the theory rather than the theory to the evidence.

Amos was not merely an optimist; Amos willed himself to be optimistic, because he had decided pessimism was stupid. When you are a pessimist and the bad thing happens, you live it twice, Amos liked to say. Once when you worry about it, and the second time when it happens.

“Belief in the Law of Small Numbers” teased out the implications of a single mental error that people commonly made—even when those people were trained statisticians. People mistook even a very small part of a thing for the whole. Even statisticians tended to leap to conclusions from inconclusively small amounts of evidence. They did this, Amos and Danny argued, because they believed—even if they did not acknowledge the belief—that any given sample of a large population was more representative of that population than it actually was.