I’m not sure if we’re living in an age of disruption or just an age that badly wants to think itself disruptive, but either way there’s been a lot of rethinking going on the past decade or so. The biggest upheavals have come in industries in which managers have always made decisions more or less by gut instinct: political campaigns, health care, military campaigns, professional sports.

The obvious cause of the turmoil is the availability of ever-cheaper computing power: People looking for an edge in any business can now gather and analyze all sorts of previously unobtainable or unanalyzable data. The less obvious cause is an idea: that the data might trump the expertise of managers. People (even experts) and industries (even old ones) can make big, systematic mistakes. You don’t set out to find better ways to value professional baseball players if you believe that the market already knows everything there is to know about their value.

There’s now a fairly long list of intellectuals responsible for the spread of this subversive idea. Somewhere near the top is economist Richard Thaler, who has just published an odd and interesting professional memoir, “Misbehaving.” It’s odd because it’s funnier and more personal than books by professors tend to be. It’s interesting because it tells the story not just of Thaler’s career but also of the field of behavioral economics – the study of actual human beings rather than the rational optimizers of classical economic theory.

For a surprisingly long time, behavioral economics was little more than weird observations made by Thaler, more or less to himself. What he calls his “first heretical thoughts” occurred while writing his graduate thesis in the 1970s. He’d set out to determine how to value a human life – so that, say, the government might decide how much to spend on some life-saving highway improvement. It sounds like a question without a clear answer but, as Thaler points out, people answer it clearly, if implicitly, when they accept money for a greater chance of dying on the job.

“Suppose I could get data on the death rates of various occupations, including dangerous ones like mining, logging and skyscraper window washing, and safer ones like farming, shop keeping and low rise window washing,” Thaler recalls. “The risky jobs should pay more than the less risky ones. Otherwise why would anyone do them?”

Using wage data and an actuarial table of mortality rates in those jobs, he calculated what people needed to be paid to risk their life. (The current implied value of an American life is $7 million.) Only he didn’t stop there. He got distracted by a funny idea.

This willingness to allow oneself to be distracted from one’s assigned task would later turn out to be a chief characteristic of behavioral economists, along with other traits not normally found in economists (but often in children): a sense of wonder, a tendency to ask embarrassing questions and a mistrust of grown-ups’ ideas about what’s worth spending time thinking about. They’re the sort of people whose day is made when they discover that health club members are most likely to hit the gym the day after receiving their monthly bill or that race-track gamblers are much more likely to bet on the long shot on the last race of the day than the first.

Thaler also was distracted by the idea of asking actual people how much they needed to be paid to run the risk of dying. He asked his students to imagine that by attending his lecture, they had exposed themselves to a rare fatal disease. There was a 1 in 1,000 chance they had caught it. There was a single dose of the antidote: How much would they be willing to pay for it?

Then he asked them the same question in a different way: How much would they demand to be paid to attend a lecture in which there is a 1 in 1,000 chance of contracting a rare fatal disease for which there was no antidote?

The questions were practically identical, but the answers people gave to them were – and are – wildly different. People would say they would pay two grand for the antidote, for instance, but wanted half a million dollars to expose themselves to the virus. “Economic theory is not alone in saying that the answers should be identical,” Thaler writes. “Logical consistency demands it.”

Thaler began to list things people did that made a mockery of economic models of rational choice. There was the guy who planned to go to the football game, changed his mind when he saw it was snowing, then changed it again when he realized he’d already bought the ticket. There was the other guy who refused to pay $10 to have someone mow his lawn but wouldn’t accept $20 to mow his neighbor’s. There was the woman who drove 10 minutes to a store to save $10 on a $45 clock radio but wouldn’t drive 10 minutes to save $10 on a $495 television.

And so on. People who read Thaler’s list might well just shrug and say, “There’s nothing here that any good used car salesman doesn’t know.” That’s the point: It’s obvious to anyone who pays any attention at all to himself or his fellow human beings that we are not maximizers or optimizers or logical or even all that sensible. When Thaler was a student, his professors didn’t argue that humans were perfectly rational but that irrationality didn’t matter, for the purpose of economic theory, because it wasn’t systematic. It could be treated as self-cancelling noise.

Enter Amos Tversky and Daniel Kahneman, psychologists at the Hebrew University in Jerusalem. Together, in the late 1960s, they had set off to confirm their suspicion that the weird self-defeating stuff that people do isn’t random and inexplicable but fundamental to human nature. More to the point, humans were not just occasionally irrational, but systematically irrational. They had predictable biases – for instance, they were inclined to draw radical conclusions from tiny amounts of information. Their preferences were unstable. Faced with a choice between two things, they responded not to the things themselves but to descriptions of those things. Perhaps most significantly, people responded very differently when a choice was framed as a loss than when it was framed as a gain. Tell a person that he had a 95 percent chance of surviving some medical procedure and he was far more likely to submit to it than if you told him he had a 5 percent chance of dying.

Tversky and Kahneman’s work sold a generation of intellectuals on a new model of human nature. Thaler didn’t need to be sold: He championed their work and created an entire field.

Twenty years ago, after Thaler received a tenured job at the University of Chicago, a reporter asked an older, more distinguished Chicago economist, who clearly saw little of use in behavioral economics, why he hadn’t blocked Thaler’s appointment. “Because each generation has got to make its own mistakes,” he said.

Today Thaler is the president of the American Economic Association and a perennial candidate for the Nobel. His rise may be just another example of the power of human misjudgment. Or he might be onto something. Either way, he’s been wildly disruptive.

Michael Lewis, a Bloomberg View columnist, is the author of “Flash Boys: A Wall Street Revolt,” “The Blind Side: Evolution of a Game,” “Moneyball: The Art of Winning an Unfair Game” and “Liar’s Poker.”