The late Daniel Kahneman (1934-2024) was an IQ researcher for the Israeli military in an era when it did a world-historical good job at figuring out who its brightest guys were.

The problem with IQ science, however, is that it gets pretty repetitious pretty quick. So with his IQ researcher pal Abram Tversky, Kahneman progressed into researching shortcomings in human cognition, for which he became extraordinarily famous among the nerdier sort of online thinkers in the early 21st century. I’m more of a glass-is-half-full guy, so I was less impressed than my peers with Kahneman’s glass-is-half-empty discoveries:

Michael Lewis’s Hot Hand
Steve Sailer
January 18, 2017

From his 1989 Wall Street memoir Liar’s Poker to his new book, The Undoing Project, Michael Lewis has succeeded his mentor Tom Wolfe as our top Southern center-right nonfiction author...

Three of Lewis’s nonfiction works have been made into hit movies: The Blind Side, Moneyball, and The Big Short. Perhaps to challenge Hollywood screenwriters to extend their range even more, Lewis has written his least filmable book yet, The Undoing Project: A Friendship That Changed Our Minds, about the Israeli psychologists Amos Tversky and Daniel Kahneman and their research into common cognitive mistakes.

In an age fascinated by artificial intelligence, Tversky (who died in 1996) and Kahneman (who is now 82) specialized in understanding “natural stupidity.” Their work won Kahneman the quasi-Nobel prize in economics in 2002.

After the 2008 financial crash, Kahneman became wildly fashionable as a corrective to the “rational man” assumption of economics. His 2011 book, Thinking, Fast and Slow, about how people make mistakes on the logic puzzles Kahneman contrived for them, was a huge best-seller (although I doubt too many people who bought it at airport bookstores ever finished it).

Now Lewis has written a biography of the two, claiming that Tversky and Kahneman had figured out the essence of Moneyball, his baseball statistics book about the 2002 Oakland A’s, decades before he’d ever heard their names. …

More generally, Lewis’s description of the breakthrough moment in the careers of the Israeli duo seems underwhelming. In the new book’s telling, Tversky explains to Kahneman an experiment involving predicting whether you’d draw a red or a white poker chip that followers of Milton Friedman saw as evidence that human beings are partly rational about making statistical forecasts.

But, Kahneman thunders, that’s just wrong. People aren’t partly rational; they are partly irrational!

Now, this may sound to you and me like a debate over whether the glass is part full or part empty, but Kahneman’s intellect is more powerful than supple.

For example, here’s one of Kahneman’s first brain twisters:

The mean I.Q. of the population of eighth-graders in a city is known to be 100. You have selected a random sample of 50 children for a study of educational achievement. The first child tested has an I.Q. of 150. What do you expect the mean I.Q. to be for the whole sample?

An I.Q. of 150 is quite rare: It should occur randomly only once out of every 2,330 people. So in this case you might well wonder whether the sample is really “random” or just how confidently it is “known” that the mean is 100.

After all, the United States military severely screwed up the scoring of their I.Q.-like AFQT enlistment test from 1976 to 1980. Senator Sam Nunn kept asking the Pentagon why sergeants were complaining to him that the military was suddenly letting in some real dumb-asses.

The brass, however, scoffed at Nunn’s lowly informants. Obviously, the sergeants were irrationally biased. What could drill instructors possibly know about psychometrics?

But after several years of denial, the Pentagon suddenly announced that their psychologists had accidentally inflated the test’s scoring.

Yet, according to Kahneman, it is irrational for you to worry about real-world concerns like these. He has stipulated that the sample is random and the mean is 100, so that’s all you need to know.

Hence, the rational answer is 101 and no other responses are acceptable.

Here’s the duo’s most celebrated trick question:

Linda is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations.

Which is more probable?

1. Linda is a bank teller.

2. Linda is a bank teller and is active in the feminist movement.

A majority of people chose the second answer, probably because they are familiar, at least in practice if not in theory, with the storytelling principle of Chekhov’s gun. The great dramatist Anton Chekhov advised:

Remove everything that has no relevance to the story. If you say in the first chapter that there is a rifle hanging on the wall, in the second or third chapter it absolutely must go off. If it’s not going to be fired, it shouldn’t be hanging there.

But what did Chekhov know about human nature? To the Aspergery Israelis, it was indisputably irrational for listeners to assume that Tversky and Kahneman didn’t just put in the details to fool them. After all, that’s exactly what the professors were trying to do: con them.

Why aren’t humans rational about noticing when they are being hoodwinked?

What’s wrong with people?

Still, although I was never as impressed with him as other top bloggers of the first decade of the 21st century were, Kahneman was a good guy. He wasn’t Chekhov, but who is?