Daniel Kahneman: ‘Everything I’ve done has been collaborative’

As I wave my plate of paella in front of the webcam, Daniel Kahneman drops the bombshell.

“I have had my lunch.”

Awkward.

A lunch over Zoom was never an especially appetising prospect, and perhaps it was too much to expect Kahneman to play along. He is, after all, 87 years old, a winner of the Nobel Memorial Prize in economics — despite being a psychologist — and, thanks to the success of his 2011 book Thinking, Fast and Slow, vastly more famous than most of his fellow laureates. For the sake of form I ask him to describe the lunch.

“Well, I had sashimi salad and shumai from a restaurant, and to be absolutely complete and precise, I had a baked apple which I baked myself.” He raises his chin in defiance, then smiles impishly. “And that was my lunch. It was fine. Not exceptional, but it was fine.”

I set my paella to one side; I am somewhat relieved. A webcam lunch promised to be as cognitively taxing as the time the FT asked me to interview the Freakonomics co-author Steven Levitt while losing to him at poker, or teach Kahneman’s biographer Michael Lewis a board game while interviewing him about The Big Short. Kahneman turns the tables on me and asks if I enjoy the challenge of juggling such tasks with an interview. Suddenly there is a slight hint of the psychotherapist about him, reinforced by his charmingly gentle Israeli accent, which is distinct even after decades living in North America.

Kahneman’s life and career defy summary. He was born while his mother was visiting Tel Aviv in 1934; his family lived in Paris and, as Jews, spent the war on the run and survived several close brushes with the Third Reich. His father died in 1944, of natural causes, and the family moved to Jerusalem in 1946.

Kahneman trained as a psychologist and became, in Lewis’s words, “a spectacularly original connoisseur of human error”. He formed an intense, productive and tempestuous intellectual partnership with Amos Tversky. The two men worked on judgment, decision-making and risk, laying the foundations for what became known as behavioural economics — and for Kahneman’s Nobel in 2002, after Tversky’s early death.

His fame has only grown since then, partly as behavioural economics has become fashionable, partly because his own work moved into another popular field, the psychology of wellbeing, and largely as the result of the blockbuster success of Thinking, Fast and Slow.

I tell him that, courtesy of that book, I have already had a memorably wonderful meal in his company. A few years ago, while travelling on business, I found myself a table for one in a Munich beer hall. I ate too many sausages and too much potato salad, drank a couple of excellent beers, and all while reading Thinking, Fast and Slow. It was one of those moments when you find yourself making a mental note that you are having a wonderful time.

Kahneman looks delighted. “I take that as a compliment, that I added to the food.”

That book described the mind’s “System 1” and “System 2”. System 1 is intuitive, effortless, while System 2 requires conscious, deliberate and effortful calculation.

I ask why the book was such a publishing phenomenon. Kahneman gives credit to his editor and also to the way the argument of the book was framed early on, with the two types of thinking described as though they were tiny decision-making agents inside each person’s brain.

“This is appealing in two ways. It corresponds to an experience people have, that some thoughts happen to them and other thoughts they produce. And the idea of presenting it as agents.”

Kahneman admits that this presentation violates the traditions of academic psychology: you’re not supposed to appeal to homunculi inside the brain. It is just a metaphor, but some professional psychologists hate it. “And the people who don’t like it feel free to despise it.”

But mostly Kahneman credits chance for the success of Thinking, Fast and Slow. Sometimes a book catches on and its popularity becomes a self-reinforcing loop. Things could easily have turned out differently. It is a modest claim, but it does neatly lead us to his new book, Noise, written with Olivier Sibony, a business school professor and former McKinsey partner, and Cass Sunstein, who is a law professor, co-author of Nudge and has been an official in both the Obama and Biden administrations.

There is a medication for noise. I mean, if you average many judgments, noise will go down

Kahneman has spent much of his life studying bias in decision-making, but noise is the other source of error. If you imagine firing arrows at a paper target, bias would be a systematic tendency for the arrows to land (say) below the bullseye. Noise would be a tendency for the arrows to err in any direction, purely at random. In some ways, noise is easier to detect. You can measure it from the back of the target, without knowing where the bullseye is. And yet noise is often overlooked.

From the viewpoint of a social scientist, this oversight is understandable. Bias feels like the thing to observe, while noise is the fog obscuring the view. Experimental methods are designed to remove noise to allow bias to be measured more clearly.

But noise is not merely an obstacle to scientific inquiry: it has real-world effects too. Kahneman and his colleagues point to insurance underwriters, judges, child-custody case managers, recruiters, patent examiners and forensic scientists, all of whom act in a way that varies from one professional to another, and between different situations, effectively at random. It is not a problem to be assumed away. So why do we pay so little attention to noise and so much attention to bias?

The problem, says Kahneman, is that we think causally, about individual cases. You can observe bias in an individual case, but to observe noise one must measure — or at least imagine — multiple cases playing out in different ways.

Can we reduce noise, I ask? Certainly.

“There is a medication for noise. I mean, if you average many judgments, noise will go down . . . if the judgments are independent, that’s guaranteed.”

But getting a second and a third opinion is expensive. And we often unconsciously suppress evidence of noise.

“People prefer their sources of information to be highly correlated. Then all the messages you get are consistent with each other and you’re comfortable.”

For example, when professors mark student exam booklets, they will often let the student’s performance on the first essay influence their judgment of the second and the third. Kahneman advises a different procedure.

“Read one question across all booklets, and you write the grade at the back of the booklet so you will not see it when you read the second question,” he explains. “The very striking thing is how less happy you are when you do it right.” To assess each essay separately gives a fairer view of the student’s overall performance — but the inconsistencies in the marks are disconcerting.

I had heard tales of how the process of writing Thinking, Fast and Slow had been agonising and interminable, so it amused me to think of Kahneman in collaboration with the absurdly prolific Sunstein, who has written nearly 50 books.

“I have a vision of the tortoise and the hare being handcuffed together,” I tell Kahneman. How did it work out?

“My first thought was that Cass would just write the book,” he says. He glances sideways and smiles broadly. “But then it turned out that I couldn’t let Cass write the book, because I’m too slow. We worked out another way of collaborating.”

“Between the three of us there is a lot of sympathy,” he says. “And so, we had fun together. It was fun to work on that book, whereas writing Thinking, Fast and Slow was a very lonely experience.”

Kahneman was widowed when the psychologist Anne Treisman died three years ago, but he does not now seem to be a lonely man. It is hard to tell over Zoom, over the 3,000 miles from Oxford to New York, but the character in front of me on the screen seems very different from the man described in Lewis’s The Undoing Project, who was depressive, insecure and needy. Lewis portrays Kahneman’s celebrated collaboration with Tversky as a true intellectual love affair, full of tantrums, envy and passionate reconciliations. The stormy relationship grew distant, then abruptly ended with Tversky’s death from cancer in 1996.

Tversky is the Lennon to Kahneman’s McCartney: the relationship between them often seemed bigger than either man alone. But Tversky was not Kahneman’s only academic partner.

“Everything I’ve done, actually, has been collaborative.”

It’s true. I’m most familiar with his work adjacent to economics, including with Richard Thaler and Angus Deaton; each subsequently won a Nobel Memorial Prize. I tell him he has good taste in economists.

“Alan Krueger was among the best of them.”

I was going to ask him about Krueger. He was a hugely respected economist who worked with Kahneman as part of what Kahneman calls “the dream team”, studying wellbeing, happiness, misery and pain. He killed himself two years ago, a loss that shook the profession.

It is hard not to wonder how Krueger’s interest in happiness and misery connects with the tragedy.

“I have no idea,” says Kahneman, shaking his head. “I don’t think being intellectually interested in wellbeing has much impact on personal wellbeing one way or another.”

I don’t think being intellectually interested in wellbeing has much impact on personal wellbeing

Still, Kahneman does now seem happy, and full of energy. I met him a decade ago, in London, and he was in considerable discomfort with a bad back. If anything he seems younger now. Covid-19 has not depressed his spirits.

“I was never afraid. It just was not a worry. And then working on the book turned out to be more pleasant. So I had a good experience, I had a good year.”

Sibony and Kahneman had been flying between New York and Paris to meet each other for days of focused work on the book. “But when Covid hit we switched to Zoom for an hour or two a day and that was immensely more productive. We might not have finished the book if it hadn’t been for the virus.”

I ask him for Zoom productivity tips, but he bats that away: he has no Zoom advice to offer.

I press him instead for a view on vaccines and the risk of blood clots, as someone who has spent a lifetime thinking about how humans respond to small risks. Do vaccine side effects loom too large in our thinking?

“It’s a standard example, I think, of a very general feature of how people think. This is a distinction between what is normal and natural, and what is artificial and human-made. The asymmetries are enormous.”

Another example, he says, is the self-driving car, which will have to be vastly safer than human drivers. “This is almost without limit. They have to be so close to perfection.”

As do vaccines, I offer.

“Yes. This idea of somebody dying from a vaccine is really almost intolerable. The idea of somebody dying from a disease . . . ” he shrugs, and raises a single eyebrow. “That’s natural. That’s the world.”

Thinking, Fast and Slow and Noise have been packaged to appear as siblings, but there is an obvious difference: Thinking, Fast and Slow was based on a lifetime of research and Noise is not. I had been wondering how to raise this, but do not need to.

“You know, the book Noise is premature,” offers Kahneman. “If I had been 20 years earlier, that’s not what I would have done. Having identified the problem of noise I would have started the research programme on noise, and given talks about it, and thought about it and written articles about it. But I started this thing very late. I started it in my eighties and you just don’t have time. This, in a serious sense, is a book that came too early. And it shows.”

He delivers this downbeat assessment in an upbeat manner. He seems cheerful at the prospect that better books on the subject will be written in the future, happy to have made a contribution while he could, and accepting of the fact that, at 87, his story cannot continue for ever.

I admit that Kahneman now feels like something of a guru to me, or more precisely a dispenser of practical wisdom, someone to whom I can come for enlightenment. Just the other day, I was walking in the park with my daughter, trying to help her think through a difficult decision, and I found myself asking what Kahneman would say about the problem.

He screws up his face at the idea.

“It’s not how I feel. I really don’t feel like a guru.”

But I press him on the matter. I once interviewed Gary Becker, another Nobel laureate and a hugely influential economist. But I don’t carry Becker around in my head to help me think through tough decisions.

“I find this very flattering and quite surprising, because subjectively many of those things that I say look pretty obvious and trite, and I hope I’m not boring people. I’m flattered, thank you. And embarrassed.”

We’ve been talking for nearly an hour and a half. The afternoon is well advanced in Manhattan; in Oxford, the sun is going down. But the conversation has no natural end. There is no espresso, no mints, no bill. (I press Kahneman to send us the receipt, but I know full well that he will not.)

So we look forward to a time when we might meet face to face once again. Kahneman once wrote: “the optimism bias may well be the most significant of the cognitive biases.” Still: despite the pandemic, the distance, his age and his busy schedule, sharing a proper lunch with him is easy to envisage. But then, my System 1 always was an optimistic fellow.

Tim Harford is an FT columnist. His book ‘How To Make The World Add Up’ was published in paperback this week

‘Noise: A Flaw in Human Judgment’ by Daniel Kahneman, Olivier Sibony and Cass Sunstein is published on May 18

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