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Book Review

How two friends upended the study of economics in “The Undoing Project”

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No one ever accused Michael Lewis of writing a dull book. “Liar’s Poker” (1989) was only the first in a series of compulsively readable take-downs of Wall Street greed and corruption produced by a journalist who began his career at Salomon Brothers. More recently, “The Big Short” (2010) and “Flash Boys” (2014) continued his exposés of financial shenanigans. “Moneyball” extended his interest in numbers games into the more genial world of baseball, depicting Billy Beane’s makeover of the Oakland A’s via a new analytical system of using player stats to craft lineups instead of the more subjective, traditional one.

Whatever subject strikes his fancy, Lewis renders it clear and understandable while showcasing its human drama. In this realm of exalted journalistic wizardry, he is surely kin to Tracy Kidder and Malcolm Gladwell.


“The Undoing Project” had its genesis in a review of “Moneyball” that cited two psychologists world famous for their pioneering research on how the mind forms judgments and makes decisions — and why the process can yield irrational results. His curiosity piqued, Lewis decided to write a book about this unlikely pair, Daniel Kahneman and Amos Tversky.

Danny (Lewis uses their first names throughout) was a post-Holocaust immigrant to Israel, pessimistic, moody, and plagued by doubt. Amos was a Sabra paratrooper, an optimistic egotistical jokester. Danny was high-maintenance, while Amos had little patience for that trait. Yet they were united, while in an Israeli army psychological unit during the 1950s, by an obsession with discovering truths on the workings of the mind.

They soon learned that, by working together, their insights multiplied and deepened. After bouncing back and forth between the United States and Israel, they finally settled in at the Oregon Research Institute. They would shut themselves in a room and discuss psychological conundrums. The chemistry, punctuated by bursts of laughter, was magical. “When one of us would say something that was off the wall,” Danny remembers, “the other would search for the virtue in it. . . . [We] kept surprising each other. . . . We were sharing a mind.”


What they discovered, through a host of simple experiments, was that people, even extremely bright people, often made bad judgments because of false assumptions, or “cognitive biases.”

In their now-famous “Linda” experiment, participants were told about an imaginary woman who was single, outspoken, very bright, and avid for social justice. Then they are asked which is more probable: that Linda is a bank teller or that Linda is a bank teller and an active feminist? Though most responded No. 2, the correct answer is No. 1, since every feminist bank teller is a bank teller. Adding a further detail only lowers the probability.

Experiments like this upended numerous principles, not only in psychology but also in economics, grounded, as it was, in notions of the “rational man” who “maximizes utility.” Because of the acclaim they ultimately earned after initial massive skepticism, Danny landed a chair at Berkeley, and Amos one at Stanford.

Lewis ably explains their discoveries, and his crisp prose has an admirable quality of cutting to the chase: “The chief feature of the Israeli army’s psychological unit in 1954 was that it had no psychologists.”

But the heart and soul of this book lies in the story of their relationship’s rise and fall. Given Amos’s more outgoing nature, the perception grew that his brilliance was primarily responsible for their breakthroughs and that Danny was the junior partner — assessments that interestingly aped the pair’s work on bias. This was so despite Amos’s insistence that Danny deserved equal credit.


It was Amos, then, not Danny, who won the MacArthur “genius” grant and was elected to the American Academy of Arts and Sciences. Danny tried to ignore professional slights like these but finally couldn’t. Mired in depression, he left his post at Berkeley, handy for collaboration with Amos, and fled 3,000 miles away to Princeton.

“Amos cast a shadow on my life,’’ he recalls. “I needed to get away. He possessed my mind.”

Thus their joyous professional marriage ended in separation, if not divorce. They worked on separate projects now, their old warmth and affection replaced by wariness. “What Danny needed,” Lewis writes, “was for Amos to continue to see him and his ideas uncritically, as he had when they were alone together in a room.” But that didn’t happen.

Then, when Amos was diagnosed with melanoma in 1991, the pendulum swung back. For his final six months, the two longtime partners joined once again in poignant embrace.

In 2002, Danny was awarded the Nobel Prize in economics, and, in 2011, his “Thinking, Fast and Slow,” a recap of his work (with and without Amos), became a bestseller. Danny may have been astounded by this unexpected turn in the spotlight, but he surely knew that Amos was right by his side.



A Friendship That Changed Our Minds

By Michael Lewis

Norton. 362 pp., $28.95

Dan Cryer, former book critic for Newsday, is author of “Being Alive and Having to Die: The Spiritual Odyssey of Forrest Church.”