Remembering Daniel Kahneman: A Mosaic of Memories and Lessons

The loss of Daniel Kahneman looms large over the behavioral sciences. The pathbreaking and Nobel-winning psychologist has died at the age of 90. His work deepened our understanding of how the mind works and how people make decisions. In doing so, it transformed the fields of psychology and economics.

His research on biases and heuristics, conducted alongside his close collaborator Amos Tversky, challenged the dominant model of human behavior in economics, one in which people act as rational utility maximizers. Kahneman and Tversky showed that our judgments err in predictable ways (biases), and we often rely on mental shortcuts to make decisions (heuristics).

Initially dismissed as describing quirks of human psychology, their research revolutionized how we understand human decision-making and contributed to the emergence of behavioral economics. For this contribution, Kahneman earned the Nobel Prize in Economics in 2002, an award Tversky would have shared if not for his untimely death in 1996. (Michael Lewis famously documented their collaboration and its impact in The Undoing Project.)

Identifying errors in judgment and choice was something Kahneman seemed called to do, particularly as it applied to his own thinking.

Kahneman brought this research to a wider audience through his 2011 book, Thinking, Fast and Slow. The book aimed to “improve the ability to identify and understand errors of judgment and choice, in others and eventually ourselves, by providing a richer and more precise language to discuss them.” For millions of readers, Thinking, Fast and Slow was their entrée into the science of decision-making.

Identifying errors in judgment and choice wasn’t just the focus of his research; it was something Kahneman seemed called to do, particularly as it applied to his own thinking.

“I get a sense of movement and discovery whenever I find a flaw in my thinking,” he said.

He once remarked to journalist Jason Zweig, who helped him with Thinking, Fast and Slow: “Do you have any idea how lucky you are to have thousands of people who can tell you you’re wrong?”

Kahneman’s ability to change his mind in light of new evidence seems to have been one of his superpowers. Is it a coincidence that the scientist who changed so many minds was also especially adept at changing his own?

Lessons like this inspired us to reach out to many of his close collaborators and colleagues to learn more about the scientist behind the science. We asked them to share a memory or a lesson they learned from him.

We bring together more than 30 entries. The authors include some of Kahneman’s first students who went on to become psychologists themselves, former graduate students and postdocs, and the psychologists, economists, and others who collaborated with or were deeply influenced by him. These contributors represent only a fraction of the people he impacted across his seven decades in the field, spent at universities in Israel, Canada, and the United States.

Is it a coincidence that the scientist who changed so many minds was also especially adept at changing his own?

The resulting collection is a mosaic of memories and lessons that helps preserve his wisdom and approach to science. You’ll learn about Kahneman the thinker, the coauthor, the emailer, as well as Kahneman the partner, mentor, and friend.

As you’ll see, his ability to interrogate his own thinking was legendary, but it wasn’t without cost. It sometimes meant hours, weeks, years on one paper, project, idea. But it was born of a desire to ask deep, meaningful questions, try to answer them rigorously, and, ultimately, get it right. Of course “right” was temporary; there was always more to learn.

Kahneman taught us that losses loom large, and his death feels especially immense. But the memories and lessons shared in this collection also remind us what we’ve gained.

— Evan Nesterak, Editor-in-Chief

Last week in Paris

By Barbara Tversky, Professor Emerita of Psychology, Stanford University

The last week in Paris. We had immersed ourselves in Les Nymphéas and Rothko, marveled at the ballet, La fille mal gardée and the opera Simon Boccanegra, walked and walked and walked in idyllic weather, devoured île flottante and chocolate mousse and soufflés, laughed and cried and dined with family and friends, among them Olivier and Anne-Lise Sibony. Took his family to his childhood home in Neuilly-sur-Seine and his playground across the river in the Jardin D’Acclimatation in the Bois de Boulogne. He wrote in the mornings; afternoons and evenings were for us in Paris. There was spare time one afternoon, what would you like to do? “I want to learn something.”

To be continued …

By Richard Thaler, Professor of Behavioral Science and Economics, University of Chicago

My fondest memories of working with Danny come from 1984 to ’85 when I spent a year visiting him in Vancouver at The University of British Columbia. Danny had just begun a new project with Jack Knetsch on what people think is fair in market transactions and they invited me to join them. We had the then-rare ability to ask survey questions to a few hundred randomly selected Canadians each week. We would draft three versions of five questions, fax them to Ottawa Monday morning, get the results faxed back to us Thursday afternoon. Who needs Mturk! We then spent the weekend digesting the results and writing new questions.

We learned that raising the price of snow shovels the morning after a blizzard might make sense to an economist, but would make customers angry. Danny displayed two of his most prominent traits. He was always a skeptic, even (especially?) about his own ideas, so we stress-tested everything. And he was infinitely patient in that pursuit. Was our finding just true for snow shovels? What about water after a hurricane? Flu medicine? How about late-season discounts (which of course are fine). It was total immersion; meeting in person several times a week and talking constantly. We were in the zone.

Although we spent another year together in New York seven years later, we were unable to recreate that intensity. We had too many other balls in the air. But we continued our conversations and friendship until the end. Every conversation ended the same way: “To be continued.”

Danny was a special man and I got to spend time with him off and on for 47 years. Which raises the question: Would it be fair for me to complain that I miss him?

“Working” with Richard Thaler

Has anything been accomplished?

By Cass Sunstein, Professor of Law, Harvard University

You are sitting in a large room—a hotel room, or perhaps an apartment. There are two of you, or maybe three. The leader of the conversation has an ironic smile, an intense look, a keen focus, mixed with a sense of pleasure, even mischief. The topic might be outrage and how to measure it. It might be group decision-making. It might be preference reversals. It might be anchoring. It might be noise, understood as unwanted variability in judgment.

The discussion starts at 11 a.m. There is a puzzle—say, the varieties of noise. What are they? Stumbling in the dark, you offer an account. The leader of the conversation looks respectful and obviously unsatisfied. He ventures an alternative account, which is infinitely better than yours. He identifies three kinds of noise. You nod in amazement. (You are thunderstruck.) He pauses and looks mildly distressed: “What I said isn’t right.” You pause. You try to help, but what you have to say is useless. He pauses and puts it another way. It is better—clearer, cleaner, more precise. He remains dissatisfied. He tries again. And again. It is time for lunch. You are already exhausted.

You keep at it. It is 6 p.m. The two or three of you have been at it for seven hours. Through the discussion, three kinds of noise have been specified, with different and better names from those Danny first suggested, and with different and better content. But Danny is unsatisfied with the names and the content; he thinks he hasn’t gotten it right and that he remains far off. In the process, you have been discussing criminal sentencing, child custody determinations, insurance companies, the social cost of carbon, x-rays, medical diagnoses, and human dignity.

You are exhausted. You can’t possibly keep track of the flood of ideas. It’s dinner time. There are smiles, and some references to the food, but the major question at dinner remains: What are the varieties of noise? And once they are specified, which is the most important? How can we measure them?

It is 10 p.m. Your mind is spinning. Has anything been accomplished? It all seems so ephemeral, lost. Danny has said 25,000 interesting things. They seem important, too. Are they gone?

In despair, you ask a version of this question. Danny responds, “Cass, you think by writing. I think by talking.”

Deadlines have no effect on me

By Olivier Sibony, Professor of Strategy, HEC Paris

One thing that I will remember Danny for is his incredible perfectionism. When we were working on Noise, he could rewrite the same sentence two, three, or ten times. His goal was to make it as short and as precise as possible. This sometimes made a paragraph harder to read. But he would never sacrifice precision for the sake of readability. Similarly, time constraints were irrelevant to him. As he once told me, “Deadlines have no effect on me. I can’t hurry even if I want to; and I don’t want to.”

Danny also worried about flaws in our work that we might have missed. Feedback from trusted colleagues who read our drafts was not sufficient to reassure him, because he knew his reputation predisposed readers favorably. This led him to a logical conclusion: “We have to pay people to tell us how bad this work is.” We hired consultants with a specific brief: to play the role of reviewers in an academic journal and look for errors in one of our chapters. It worked. They found flaws, and we fixed them.

Thinking by talking (and writing) with Olivier Sibony and Cass Sunstein

That was wonderful. I was wrong.

By Adam Grant, Professor of Management and Psychology, University of Pennsylvania

I gave a talk on some of my research on givers and takers. I didn’t realize that Danny Kahneman was in the audience. As I’m walking offstage, Danny is there. He stops me, and he says, “That was wonderful. I was wrong.” His eyes twinkled as he said it, and he lit up.

Danny is not somebody who walks around beaming all the time, so I was struck by the reaction and intrigued by these two sentences that normally would contradict each other. Normally, what you expect people to say is, “That was wonderful, I was right.” Or, “Actually, you’re wrong. Let me tell you why.”

I ended up sitting down with him and asking him to explain this reaction. I said, I’ve seen this a couple times—I’ve seen you make predictions, people end up running the experiment and you see something that’s not what you expected, and you seem to really take joy in being wrong. The first thing he said was something to the effect of, No one enjoys being wrong, but I do enjoy having been wrong, because it means I am now less wrong than I was before.

But what’s different about Danny is he seems to do that even when his core beliefs are attacked or threatened. He seems to take joy in having been wrong, even on things that he believes deeply. And so I asked him about that—why and how?

On the why question, he said, Finding out that I was wrong is the only way I’m sure that I’ve learned anything. Otherwise, I’m just going around and living in a world that’s dominated by confirmation bias, or desirability bias. And I’m just affirming the things I already think I know.

On the how part, he said for him it’s about attachment. He thinks there are good ideas everywhere, and his attachment to his ideas is very provisional. He doesn’t fall in love with them, they don’t become part of his identity.

He had that ability to detach and say, look, your ideas are not your identity. They’re just hypotheses. Sometimes they’re accurate. More often, they’re wrong or incomplete. And that’s part of what being not only a social scientist, but just a good thinker, is all about.

Excerpted from a conversation with Adam Grant for Behavioral Scientist.

I’m more like a spiral than a circle

By Dan Lovallo, Professor of Strategy, Innovation and Decision Sciences, University of Sydney

Many people have heard that Danny changes his mind—a lot. This is certainly true. I have never written even a 5,000-word essay with him that didn’t take a year. Let me add another dimension to the discussion. During our last working dinner at a bistro in New York, and possibly out of mild frustration, I said, “Danny, you know you change your mind a lot.” It wasn’t a question. He continued chewing. I continued my line of non-question questioning: “And often you change it back to what it was at the beginning.”

Danny, having finished his bite and without missing a beat, looked up and in his characteristic lilt said, “Dan, that’s when I learn the most.” Then using his finger he drew a circle in space. “I don’t go around and around a problem. It might seem like it, but I am getting deeper and deeper.” The circle morphed into a three-dimensional spiral. “So, you’re missing all the learning,” he explained, as he displayed the invisible sculpture. “I’m more like a spiral than a circle.” Happy with this new idea, Danny grinned as only Danny could.

Studying with Moses

By Carey Morewedge, Professor of Marketing, Boston University

I had the fortune to be Danny Kahneman’s last postdoc. It initially felt like going to study with Moses, but a modern version with a love of Scandinavian recliners who offered you an espresso as you walked into the door. Working with Danny fundamentally changed my model of human judgment and decision-making. When I first arrived in Princeton, he told me to get the latest textbook on visual illusions and see if there was anything the field missed.

Danny saw the mind through the architecture of the eye and believed the eye and mind have similar illusions, blind spots, and mechanisms. That simple, elegant insight gave rise to much of the field we know today. Each conversation with Danny left me smarter, humbler about what I knew, and wildly overcaffeinated. Despite his stature, he seriously considered our scientific disagreements and verbally “preregistered” the evidence that would change his mind.

Danny was generous with his time and the experiences that he shared. He and Anne Treisman would often take me to lunch to talk psychology. At the time, I had no idea where they were taking me. The lunches were just fantastic conversations. Later, I realized that one “nice place” in Berkeley had been Chez Panisse.

Beyond being a closeted foodie, Danny was also a romantic. He would pick up Anne from Green Hall in their pristine 1990s Honda Accord almost every day I met with him in Princeton. During seminars, one of them would often fall asleep, head rested on the other’s shoulder. After I moved to Pittsburgh, Danny frequently flew me back to meet with him in his home, whether in Princeton or Berkeley. I hope it was because he enjoyed our conversations and collaboration. I can’t help thinking it was partly because it helped me afford the many flights I took to see my girlfriend (and future wife), Mina Cikara. I had fallen in love with Mina while in Princeton, and she was still living there at the time.

A case in character

By Angela Duckworth, Professor of Psychology, University of Pennsylvania

One evening, more than twenty years ago, I was the last one in the lab when the phone rang. “Hello?” I said, I hope not brusquely. I was a Ph.D. student at the time and eager to get back to my work. “Hello?” came the reply of an uncommonly polite older gentleman, whose accent I couldn’t quite place. “I’m so sorry to trouble you,” he continued. “I believe I’ve just now left my suitcase there.” Ah, this made sense. We’d hosted an academic conference that day. “It’s a terrible inconvenience, I know, but might you keep it somewhere until I can return to pick it up?” “Sure,” I said, cradling the receiver and grabbing a notepad. “How do you spell your name?” “Thank you so very much. It’s K-A-H-N-E-M-A-N.” I just about fainted. “Yes, Dr. Kahneman,” I said, coming to my senses, likely more deferentially than when I’d first picked up.

When I hung up, I thought to myself, Oh, it’s possible to be a world-famous genius—the most recently anointed Nobel laureate in economics, among other honors—and interact with anybody and everybody with utmost respect and dignity, no matter who they are. In the years that followed, I got to know Danny Kahneman much better, and when I did, that view was only confirmed. Confirmation bias? Halo effect? No and no. What then? Character. The world is mourning the loss of Danny Kahneman the genius, as we should, but I am missing Danny Kahneman the person.

Merely average

By Donald Redelmeier, Professor of Medicine, University of Toronto

I first heard about Daniel Kahneman when I was in high school. We later met when I was in graduate studies at Stanford. The two of us stayed connected for the next three decades. Kahneman had superb insights on intuitive judgment, cognitive psychology, and behavioral economics. He was also a smart, diligent, efficient, honest, savvy, and generous scientist throughout. I was not surprised when he won a Nobel Prize.

Kahneman, however, was merely average when driving. We drove together several times and he was no better than me at anticipating other vehicles, visualizing traffic flows, staying unrushed, and avoiding pejoratives. This shows how excellence in science does not necessarily extend to other domains. Unlike average drivers, however, he recognized his limits behind the wheel and did not consider himself as better than average.

This humility saved Kahneman from uncountable traffic crashes because he knew his limits and compensated accordingly. The same humility was true in his science because he always worried about mistakes and actively sought contrary views to detect errors. That’s a strength of being open-minded and soliciting alternate perspectives. His self-disciplined humility is a trait worth emulating by all of us in behavioral science.

I hated it so much

By Linnea Gandhi, Ph.D. Candidate, University of Pennsylvania

“I hated it so much that it clarified what I wanted to say.” After working late to write a memo that, I hoped, captured both Danny’s thinking and his voice, I woke up a few hours later to those words. Normally, that sort of feedback from a collaborator would devastate me. With Danny though, this was not only normal but a compliment.

Danny believed in “no sunk costs” when it came to iterating on ideas, especially in writing. Sometimes he didn’t even track changes. Every draft served a purpose—to inspire a better one—after which it was no longer needed. Ego was irrelevant. If anything, you knew Danny genuinely cared about you as a collaborator merely because he welcomed you into his process and was (nearly) as hard on you as he was on himself. He never let you question your worth. The drafts lasted hours, the relationships lasted years.

I wish he were around to hate more of what I wrote.

My objection is fatal

By Shane Frederick, Professor of Marketing, Yale University

I once asked Danny to comment on a paper I was about to submit. His response:

“Shane, I was hoping to like your paper, but I did not. You lost me once I understood what you were doing. Since my objection, if valid, is fatal, there is nothing that you could do that would fix it. So you should hope that the referees don’t agree with me. I join you in that hope.”

Another time, he reached out at 10:30 p.m. on a Monday:

Danny: “Shane, are you watching the game?”

Shane (super puzzled, since I didn’t think he followed football): “No.”

Danny: “Fantastic. I want to talk about heuristics.”

Never finished thinking

By Benjamin Manning, Ph.D. Student, Massachusetts Institute of Technology

What I will remember most about Danny is not the content of our conversations but the hours that followed.

Danny’s way of extending care and humility was touching. Despite the occasional tension in our discussions, a common occurrence when academics argue over experimental design, he would always reach out to check in, unduly apologizing for any perceived stubbornness or insensitivity. He, the Nobel Prize winner, the bestselling author, and the smartest person in the room, often needlessly apologized to us!

Danny also was never finished thinking about anything. There was always another layer. We would agree that an idea was sound, that we should move forward with the experiment. But two hours later (a bit after the apology call), we would get a message telling us we were all wrong and we had to rethink everything. Of course, he was usually right.

When this kept happening, I tried to anticipate his critiques. I would think for hours after our conversations. Where was that deeper level of understanding? Unsurprisingly, I could not find it. I’d be convinced that our plan was right. Boom—10 minutes later, an email highlighting a problem so clearly. I had known there were other layers, but I just could not see them. Danny, however, always saw more.

Now it is time that we turn on ourselves

By David Schkade, Professor Emeritus of Management and Strategy, University of California, San Diego

Danny was what I called a “serial monogamist” with his ideas and hypotheses. He loved his current favorite idea with all his heart and worked relentlessly to make it the best it could be. Careful empirical tests were then designed, with much effort to make the result as fair and as convincing as possible (usually large samples and between-group comparisons). But in the end, the empirical evidence was always the decision maker. If it did not support the cherished hypothesis, then he abandoned it. Sunk costs did not matter. If it wasn’t true, he was on to the next idea, which he loved with all his heart … and there were always more ideas.

But if the data was supportive, at first there was excitement. But then, he would say, “Now it is time that we turn on ourselves,” time to try to critique and tear down what we had just built. Better that we do it to ourselves than to leave it for our critics to do, he would say. He was more concerned with getting it right than a rush to publish. Although he could seem to be in a hurry in some ways, he was very patient in “getting it right.”

Just wait, it’s going to change everything

By Barry Schwartz, Professor Emeritus of Psychology, Swarthmore College

It was 1983, and I was working on a book that aimed to be a systematic critique of conceptions of human nature shared by economics, evolutionary biology, and Skinnerian psychology. I was an “expert” on Skinner, but very much an amateur when it came to the other two fields. In my critique of economics, my plan was to show that a slew of assumptions economists made about what people valued, what they cared about, and how they made decisions were wrong.

The work of Kahneman and Amos Tversky was to be a central part of my argument. But I was on shaky ground, preparing to make sweeping claims on the basis of what might have been very superficial understanding of their work and its implications. So I made appointments to see each of them—Tversky at Stanford and Kahneman at Berkeley—to lay out my arguments and give them a chance to educate me and protect me from embarrassing myself.

Both conversations went more or less the same way. At that moment in history, their work was mostly regarded as the discovery of a set of quirks and imperfections in decision-making that pretty much left the edifice of economic rationality intact. But their work, I argued, would revolutionize how economists think about human aspirations and decisions. It would revolutionize how we all think about what it means to be rational. Just wait, I said. It’s going to change everything.

Each of them, in their own way, tried to calm me down. Danny said that he rarely found himself in the position of defending economics, but my grandiose claims on his behalf had put him in that position. Yes, he agreed, their work might prove to be important, but it wasn’t going to turn anything upside down. He was kind and gentle as he tried to save me from public humiliation.

I left the conversations with each of them even more convinced that their discoveries would be world-changing. They failed to talk me out of my view. I wrote my book, The Battle for Human Nature. Essentially nobody bought it—the book or the argument. Nonetheless, I think the following 40 years have shown that I was right.

I interacted with Danny many times over the years since that conversation, which surely loomed much larger in my mind than his. But that initial conversation remains a jewel in my professional life, never to be forgotten.

The Nobel Prize award ceremony

Better act like you are surprised

By Craig Fox, Professor of Management, University of California, Los Angeles

Within the first five minutes of Danny Kahneman’s class in judgment and decision making at UC Berkeley, I was hooked. Two weeks into the class I had a feeling I might have found my future career. What better way to spend one’s days than to study how to help people make better decisions for a better life?

As an undergraduate working in Danny’s lab, he always treated me with greater kindness and consideration than I thought a random undergraduate deserved, and he showed a bafflingly keen interest in my success. Nevertheless, I was surprised one Saturday morning in February when the phone rang in my apartment and it was him.

“Craig, this is Danny. I just wanted to call to congratulate you!”

“Thanks,” I replied reflexively. But I had no idea what he was talking about.

“Congratulations for what?”

“Oh, you haven’t heard?” he replied. “Well, you’ve been admitted to Stanford’s psychology department. And not only that, you’ll be working with Amos.”

I was beyond thrilled. Stanford was my first choice for graduate school, and the opportunity to study with Amos Tversky was a dream come true. We chatted for a few more minutes about this news and what it would mean for me, and then said goodbye.

Five minutes later, the phone rang again. It was that same familiar voice.

“Craig, this is Danny.” He paused, awkwardly, then continued: “When Stanford calls … better act like you are surprised.”

An inch taller and in love

By Maya Bar-Hillel, Professor Emeritus of Psychology, Hebrew University of Jerusalem

My first memory of Danny Kahneman goes back to 1963. I had just ended my service in the Israeli army, and was enrolled in The Hebrew University’s psychology department, the only department, besides the medical school, which at that time selected students on the basis of a competitive psychometric test. Danny taught the freshman course Introductory Statistics. He walked into a class brimming with the eager minds and shiny eyes of novices to the academic world. Tall and handsome, he greeted the class warmly, and immediately announced that we were “the crème de la crème.”

At the end of the class, I was an inch taller, and in love—with Danny, with Statistics, with the University. I graduated from that department, years later even joining its faculty, but Danny remained till his death the person to share my work and writing and ideas with, and who, while giving sharp criticism, still always made me feel like I was the crème de la crème. Thank you, beloved Danny. I will miss you.

He gave us confidence

By Lord Richard Layard, Professor Emeritus of Economics, London School of Economics

Danny changed my life. He first persuaded me that happiness could be measured. Then he twice invited me to Princeton for a month each time. We had many memorable lunches. Danny introduced me to many key people, especially Richard Davidson. But more importantly, he came to every conference we had in England—I can remember at least six. We also had regular phone calls. Without his wisdom (and his credibility from the prize) well-being would never have progressed as it has in Britain. He gave us confidence.

But, most importantly, it was so enjoyable to be with him. He was incredibly open and sweet-natured. And I am so glad he had those years with Barbara, which made him very happy. He was a real giant whose influence can only grow and grow.

Top row: with daughter Lenore; Second row: walking with Richard Thaler, with wife, psychologist Anne Treisman; Third row: at the Nobel Prize ceremony, with David Schkade; Fourth row: with Avishai Henik, receiving the Presidential Medal of Freedom from President Barack Obama; Final row: with wife, psychologist Anne Treisman

Anxious and unsure

By Eric Johnson, Professor of Business, Columbia University

A few months before the publication of Thinking, Fast and Slow in 2011, the Center for Decision Sciences had scheduled Danny to present in our seminar series. We were excited because he had decided to present his first “book talk” with us. Expecting a healthy crowd, we scheduled the talk in Uris 301, the biggest classroom in Columbia Business School.

I arrived in the room a half hour early to find Danny, sitting alone in the large room, obsessing over his laptop. He confided that he had just changed two-thirds of the slides for the talk and was quite anxious and unsure about how to present the material. Of course, after the introduction, Danny presented in his usual charming, erudite style, communicating the distinction between System 1 and System 2 with clarity to an engaged audience. Afterwards, I asked him how he thought it went, and he said, “It was awful, but at least now I know how to make it better.” Needless to say, the book went on to become an international bestseller.

This was not false modesty. Having studied overconfidence throughout his career, Danny seemed immune to its effects. While surely maddening to some coauthors, this resulted in work that was more insightful and, most importantly to Danny and to us, correct. He was not always right, but always responsive to evidence, supportive or contradictory. For example, when some of the evidence cited in the book was questioned as a result of the replication crisis in psychology, Danny revised his opinion, writing in the comments of a critical blog: “I placed too much faith in underpowered studies.”

The best tribute to Danny, I believe, is adopting this idea, that science and particularly the social sciences, is not about seeming right, but instead, being truthful.

A beginner’s mind

By Jason Zweig, Columnist, The Wall Street Journal

Working on Thinking, Fast and Slow exposed me to three of Danny’s qualities I hadn’t previously encountered in their full intensity. Only years later did I realize that I’ve internalized them as a journalist and an investor. Or so I hope.

First, Danny saw everything through a child’s eyes or, as some people call it, “beginner’s mind.” No one else I’ve ever known has so often asked: Why? Instead of assuming the status quo is valid, Danny always started by wondering whether it made any sense.

He was also relentlessly self-critical. I once showed him a letter I’d gotten from a reader telling me—correctly but rudely—that I was wrong about something. “Do you have any idea how lucky you are to have thousands of people who can tell you you’re wrong?” Danny said.

Finally, Danny could rework what we had already done as if it had never existed. Most people hate changing their mind; he liked nothing better, when the evidence justified it. “I have no sunk costs,” he would say.

One of his favorite words, while working on the book, was “miserable.” He used it to describe whatever we had just written; the process of writing a book; and, above all, himself. Danny’s misery was largely rooted in the decades he and Amos had spent exploring the failings of the human mind by picking apart their own errors of thought and judgment.

Taking the outside view on everything else had given Danny the outside view on himself. He embodied the ultimate form of self-knowledge: to distrust yourself above all. He knew full well how smart he was, but he also knew how foolish he could be.

Noticing that he intuitively stereotyped a bespectacled child as “the young professor,” Danny realized people extrapolate the future from almost no data at all. After buying an expensive apartment, he laughed at knowing that he would also overpay to furnish it.

Excerpted with permission from an article that originally appeared in The Wall Street Journal.

Kahneman and Tversky 101

By Max Bazerman, Professor of Business Administration, Harvard University

Many scholars had the good fortune to study with Danny. Some were his students, postdocs, or served on the same faculty. I was jealous of these scholars. I write as one of the thousands of more distant students of Danny’s. I benefited from having an early fascination with the work of Kahneman and Tversky. Kahneman and Tversky’s use of rationality as a goal post against which actual decision-making could be systematically described became the orientation for my research and teaching in decision-making, negotiation, and ethics. My research and life experiences have been greatly enhanced by the Kahneman and Tversky lens.

Danny and I interacted occasionally over the three decades after I first met him at a conference in 1984. Before the term “behavioral economics” existed, Danny heard that I taught what I often described as “Kahneman and Tversky 101.” In 1993, when Danny took a position at Princeton, and would be teaching public policy students, he flew to Chicago to watch me teach Kahneman and Tversky 101 to executives at Northwestern. He was surprised to see me highlight in class the systematic mistakes that students made; his style was gentler, highlighting the mistakes of others.

In 2005, I had the wonderful opportunity to co-teach decision-making with Danny for a large company, an experience that was truly memorable—he would continue to disagree with my approach, while being happy to engage in discussions about the best way to improve decision-making. The goal was discovery, not winning the argument.

Our relationship became much closer in 2013, when we worked together helping an insurance company improve their agreements. Throughout the project, I learned so much by watching Danny’s openness to the ideas of others, his passion for making better decisions, and his focus on helping the company achieve fair policies. This collaboration was one of the most profound professional experiences of my life.

With Amos Tversky

Practical problem solving

By Todd Rogers, Professor of Public Policy, Harvard University

I was part of a group helping some political candidates think about how to respond to untrue attacks by their political rivals. We focused on what cognitive and social psychology said about persuasive messaging. Danny suggested a different emphasis I hadn’t considered.

He directed us to a literature in cognitive psychology on cognitive associations. Once established, associations cannot simply be severed; attempting to directly refute them often reinforces them, and logical arguments alone can’t undo them. But these associations can be weakened when other competing associations are created.

For instance, if falsely accused of enjoying watching baseball, I’d be better off highlighting genuine interests—like my enjoyment of watching American football or reality TV—to dilute the false association with baseball. This anecdote is one small example of the many ways Danny’s profound intellect has influenced practical problem-solving. He’ll be missed and remembered.

Premortems

By Michael Mauboussin, Head of Consilient Research, Morgan Stanley

The opportunity to spend time with Danny and the chance to interview him were professional delights. One of my favorite lessons was about premortems, a technique developed by Gary Klein that Danny called one of his favorite debiasing techniques. In a premortem, a group assumes that they have made a decision (which they have yet to do), places themselves in the future (generally a year from now), and pretends that it worked out poorly. Each member independently writes down the reasons for the failure.

Klein suggested that one of the keys to premortems was the idea of prospective hindsight, that putting yourself into the future and thinking about the present opens up the mind to unconsidered yet relevant potential outcomes. I then learned that the findings of the research on prospective hindsight had failed to replicate—which made me question the value of the technique.

Danny explained that my concern was misplaced and that prospective hindsight was not central to the premortem. Rather, it was that the technique legitimizes dissent and allows organizations the opportunities to consider and close potential loopholes in their plans. That I had missed the real power of the premortem was a revelation and a relief, providing me with a cherished lesson.

Dancing dissonance

By Katy Milkman, Professor of Operations, Information and Decisions, University of Pennsylvania

One of my fondest and most awkward memories of Danny is of a visit I made to his New York apartment in 2019 to conduct a recorded interview about his work on prospect theory for a podcast I host about behavioral science called Choiceology.

I remember sitting down in Danny’s living room across from him and waiting while a sound engineer placed a fancy portable microphone in front of his mouth, which Danny found enormously uncomfortable. Despite wanting to do nothing more than move that mic, and giving it the stink eye throughout our conversation, Danny was incredibly gracious. He gave a terrifically thoughtful interview, and he even made the time to take me out for lunch afterwards at his favorite neighborhood Japanese restaurant.

Over that simple meal, we had a wide-ranging conversation about the state of our field (he was very concerned about the replicability crisis; a concern I shared), his latest book project (he was working on Noise at the time), and our hobbies. There was a particularly memorable moment when Danny told me how much he loved watching dance performances, and I replied by asking if he’d ever wanted to try dancing himself. What I’d thought was a reasonable question clearly was not, as it earned me a wilting look and a vehement “No!” I made a mental note at that moment to avoid heated intellectual arguments with Danny!

I also vividly recall talking with Danny about his experience winning the Nobel Prize. He explained to me that the best thing about winning it, by far, was how happy it made all the people around him—even his casual acquaintances. He said their joy was by far his greatest source of delight; it caught him by surprise but was truly wonderful.

Subject: moment of pride

By Avishai Henik, Professor Emeritus of Psychology, Ben Gurion University of the Negev

Over fifty years ago I was an undergraduate in Danny’s classes in the new psychology program at Be’er-Sheva. Danny taught without any written material in front of him. He would enter the class, ask one of the students where we finished off the previous week and from there, he would continue lecturing. One day he needed something written for the corresponding class at the Hebrew University in Jerusalem. Because I was a diligent student who wrote down everything the teacher said, he asked me for my notebooks, promising I would get them back.

At the time I used to be called to reserve duties in the military every year. Not surprisingly, it also happened during the year we studied perception. Hoping that I would have some time to study for the expected exam, I asked Danny what and how to study. Danny told me that I should read and know the textbook. I asked in what way I should know this book, and Danny, with no hesitation responded: “By rote of course.” I followed Danny’s advice. I still remember the sense of competence that I had during the exam. Danny was impressed.

We published an article on social priming that was replicated. I received the following email from Danny.

What happened to brilliant?

By Tom Gilovich, Professor of Psychology, Cornell University

To make the kind of contributions Danny has made, it’s essential to look at things from several angles, to zoom in and zoom out on a problem, and to be self-critical. And Danny’s capacity to do so was legendary. Most notably, he was often in a lather about how Thinking, Fast and Slow would not only fail to have much impact, but might be an embarrassing end to his career.

Naturally, Danny’s ability to be self-critical had implications for those who worked with him. Collaborators had to accept that the journey would not be smooth. I experienced this firsthand when Vicki Medvec and I submitted a chapter for a book for which Danny wrote a final-chapter commentary. I don’t remember whether I knew he was assigned that role, but I do remember being very surprised—and thrilled—when I checked my phone messages and heard, “This is Danny Kahneman and I want to tell you that your chapter is brilliant. Reading it made my day.”

I didn’t know him then, so to receive that feedback from psychology’s Mount Olympus … talk about making one’s day! I don’t believe my feet touched the ground until I realized that I stupidly deleted the message rather keep it forever to play for anyone who’d listen.

My feet became even more anchored to the ground a week later when I got another call from Danny: “I’ve been thinking more about your chapter. It’s all wrong. I believe you’re planning to publish the data you describe in the chapter, but you can’t. People will go after you. It will damage your career.” Eeek! What happened to “brilliant”?

This story has a happy ending because Danny’s second thoughts on our work resulted in an adversarial collaboration with him that led to a broader perspective on the psychology of regret. Danny’s habit of looking at a problem from different perspectives once again paid off in greater insight.

Don’t take rejection to heart

By Anat Ninio, Professor Emeritus of Psychology, Hebrew University of Jerusalem

For about five years, I was Danny’s student, supervisee, research assistant, teaching assistant, and sometimes secretary. What I hadn’t expected but turned out to be a valuable part of our relationship was his advice on the right way to be a successful academic. One wise sentence I keep repeating in his name to young hopefuls is the strategy of sending your work out for publication. Danny told me to start with the top journal in the field, and ignore its very high refusal rate. He said that even if the manuscript gets rejected, you end up with intelligent comments from the reviewers. Treat them as valuable feedback, use them to better your manuscript, and then send it to the next journal in the hierarchy. Don’t take the rejection to heart—turn it into an opportunity. This advice serves very well even for young children, fostering a willingness to dare to fail.

Stay receptive to criticism

By Andrei Shleifer, Professor of Economics, Harvard University

I met Danny Kahneman in the 1980s at a behavioral economics conference in New York. Although his research would end up shaping and inspiring much of mine for the next 40 years, I did not yet know that. In fact, I did not get to know Danny well until we had a long walk in Princeton after Amos Tversky’s death. After that, I tried as often as I could to run ideas by him, benefit from his wisdom, and just enjoy his patient and sympathetic company.

Two Danny experiences are vivid in my memory. About 20 years ago, I became increasingly skeptical about prospect theory, and my research started moving in the direction of memory, attention, and cognition more generally. I was particularly worked up about the “rare Asian disease experiment,” which to me had to do with framing and representation of the problem, and not with loss aversion in the value function. I did not get a warm reaction to these digressions from behavioral economists, for whom prospect theory ruled. But the person who wanted to engage, to think it through, and to stay receptive to criticisms, was of all people Danny. He stayed curious.

We last had lunch in New York in November 2023. He was as sharp as ever. Seeking his wisdom, I asked him why my papers on cognition in economics were being ignored by psychologists, despite being so respectful of that field. He told me that he thought memory and attention were whole fields in psychology, and the idea that these mechanisms can be integrated into a general model of cognition and choice was unlikely to gain a warm reception. This is not what I wanted to hear, but I also understood that Danny was thoughtful, sincere, wise, and probably, as usual, correct.

The early years

By Daniel Gopher, Professor Emeritus of Psychology, Technion—Israel Institute of Technology

I graduated in 1972 at the Hebrew University of Jerusalem. Daniel Kahneman was my advisor and I was his first graduating Ph.D. student. These were the early years before Danny met Amos Tversky. Attention was the main research focus for Danny, his laboratory, and his students. I was fortunate to be a member of this exciting group and participate in many long hours of discussions.

We enjoyed his creativity and brilliant ideas while mentoring and encouraging open discussions. We were motivated by his bright-eyed excitement and interest. His first book, Attention and Effort, draws upon the discussions and conducted research in this framework.

Danny was interested not only in the scientific contribution of his attention research but also its implication to daily life performance. He introduced the term “attention limits” to pilots’ education and together with me developed an auditory test of selective attention test, which was validated and incorporated in the selection battery of Israel air force flight school and also tested on bus drivers.

We worked closely for several years. I consider him my guide and mentor of how knowledge should be acquired and questioned, how research should be designed and conducted, and how to get students involved. These early years of mentoring have stayed with me through my years in academia and applied work.

Hours talking

By Annie Duke, Psychologist, Former Professional Poker Player, and Co-Founder of the Alliance for Decision Education

Danny was generous with his friendship, generous with his time, generous as a collaborator. He was just so incredibly kind.

I had the privilege of getting introduced to Danny by Josh Wolfe right after my book, Thinking in Bets, came out. I remember being so nervous as I waited in the restaurant where we were to have lunch. I mean, after all, Danny was an idol of mine. His work was the single biggest influence on my thinking about decision-making.

But from the first moment he sat down, he was so welcoming. Danny was possibly the lowest ego person I have ever met, certainly in comparison to the outsized volume and quality of work he produced in his life. As we chatted, he was much more curious to learn about decision-making at the poker table than to talk about his own work. He made me feel like I was his equal in that conversation even as I was lightyears behind him.

When I was writing Quit, Danny spent hours and hours on Zoom with me talking through the subject. He read early drafts and offered edits. It is still hard for me to fathom that Danny took the time to do that. But that is who he was. The book is, of course, so much better for his contribution. Quit was deeply informed by his body of work, and having the opportunity to collaborate with him is hard to comprehend for me even now. I am not sure how I got so lucky. But I am so grateful that I did.

Excerpted with permission from Annie Duke’s newsletter, Thinking in Bets.

I took Danny’s advice

By Terrance Odean, Professor of Finance, University of California, Berkeley

In the spring of 1989, I asked Danny Kahneman for advice about grad school. He invited me to his house on Saturday morning. I was currently enrolled in a UC Berkeley cognitive psychology course co-taught by Danny and his wife, Anne Treisman. The previous semester, I had taken Danny’s judgment and decision-making course.

When I arrived Saturday morning, I told Danny that I wanted to pursue a Ph.D. in psychology and study with him. He responded that if I really wanted to study psychology, he would be happy to have me as a student. However, there was another field that he thought I should consider: finance. Danny thought that I should take insights from judgment and decision-making and apply them to finance. I could be one of the early researchers in behavioral finance—a very small field at the time.

Danny was particularly concerned about my family. My wife, Martha, and I had two daughters—our third daughter was born while I was in graduate school. Martha was from Berkeley and wanted to raise our daughters here. Danny told me that if I got a Ph.D. in psychology, I’d likely end up with a job somewhere Martha and I didn’t want to live and with a lower salary than we might have hoped for.

If, as he expected, behavioral finance took off, I would have more job choices and better pay. He cautioned, though, that behavioral finance might not get me a job. But, in that case, I would have a Ph.D. in finance, go into industry, make more money, and be able to keep my family in the Bay Area.

I took Danny’s advice. In graduate school, I often felt as though I were a missionary banished to a foreign land. The people were friendly but saw the world quite differently. And then, as Danny had predicted, behavioral finance took off. And my daughters grew up in Berkeley.

It’s a hell of a thing

By Colin Camerer, Professor of Behavioral Economics, California Institute of Technology

In the mid-1990s, I met Danny at his gorgeous house in Berkeley to talk about utility. He and Barbara Fredrickson, and others, had been finding that remembered evaluations, like reminiscing about a vacation, were not mathematical integrals of momentary hedonics. Time duration was neglected, and the best and last moments were too heavily weighted (a “peak-end rule”).

Both of us liked to “think by talking.” But Danny was a master of an extra level—thinking by conversing, like idea tennis. I wasn’t. And Danny was notoriously pessimistic; he wanted a gardener to weed out bad ideas. But all his ideas were so intriguing; I didn’t see weeds.

Danny and most early behavioral economists used all parts of life as data. In 1991–92, we had a dream sabbatical together at the Russell Sage Foundation in New York along with Dick Thaler. We went to see a Western, The Unforgiven. Clint Eastwood’s character says, about a murder, “It’s a hell of a thing killing a man. You take away all he’s got, and all he’s ever gonna have.” Danny was fascinated by this.

Five years later, scientific descendants of “all he’s got” and “all he’s ever gonna have” showed up as “remembered utility” and “predicted utility” in The Quarterly Journal of Economics.

Eradicating unhappiness

By George Loewenstein, Professor of Economics and Psychology, Carnegie Mellon University

For Danny, research was intensely personal. He got into intellectual disputes with a wide range of people, and these would hurt him viscerally, in part because it pained him that people he respected could come to different conclusions from those he held so strongly. He came up with, or at least embraced, the concept of “adversarial collaboration” in which researchers who disagreed on key issues would, however, agree upon a definitive test to determine where reality lay. A few of these were successful, but others (I would say most) ended with both parties unmoved, perhaps reflecting Robert Abelson’s insight that “beliefs are like possessions,” and, hence subject to the endowment effect.

I was spending time with Danny when he first got interested in hedonics—happiness—and that was a personal matter as well. His mother was declining mentally in France, and he agonized about whether to visit her; the issue was that she had anterograde amnesia, so he knew that she would forget his visit as soon as it ended. The criterion for quality of life, he had decided, should be the integral of happiness over time; so that—although she would miss out on the pleasure of remembering it—his visit would have value if she enjoyed it while it was happening.

Showing the flexibility of his thinking, and his all-too-rare willingness to learn from the data, his perspective changed as he studied happiness. He became more concerned about the story a life tells, including, notably, its peak and end; he concluded that eradicating unhappiness was a more important goal than fostering happiness, and began to draw a sharp distinction between happiness and life satisfaction, perhaps drawing, again, on his own experience. He always seemed to me to be extremely high in life satisfaction, but considerably less so in happiness.

Why do people care about things they will never know?

By Ilana Ritov, Professor of Psychology, Hebrew University of Jerusalem

I’ve had the opportunity to work with Danny quite intensively on the topic of evaluation of public goods. I found it extraordinary that he would rethink every idea at any stage of the research, and restart writing a paper as many times as he thought were needed, even when we got to version thirty-something of it. While this made working with him frustrating, it was incredibly inspiring.

But my first meeting with Danny was quite different. I came to consult with him about a paper I wrote with Jon Baron on compensation of accident victims. This discussion with Danny developed in an unexpected direction: Why do people care about things they will never know, because these things are only revealed posthumously?

Danny was intrigued by the thought that we care about what people will know or think about us after we die. To examine this idea, we contemplated various unusual scenarios: a beloved spouse who turned out to have been unfaithful, a work of art that the deceased was a proud owner of but later was revealed as a fraud, a scientist whose big discovery came into question, and so on. Danny seemed intrigued and amused by thinking of people’s misperceptions related to their own death, unable to grasp that they would no longer be alive.

A joke—the hard part

By Daniel Read, Professor of Behavioural Science, University of Warwick

Danny once told me a joke which has persisted with me, partly due to its crypticness, partly to its profundity. A mathematician, he said, announced that he had discovered a proof of Fermat’s last theorem and almost solved it. He had divided the problem into two parts, a hard part and an easy part, and the part he completed had been the hard part.

Danny did not really explain this joke. I think one reason it sticks in my mind is that it does not allow for an easy interpretation. It’s like one of those aphorisms a mystic tells when the seeker for truth finally finds them on top of a mountain. The reality is that I repeated this story a few times, and I felt no one understood it so I stopped repeating it, but I did not stop thinking about it.

I interpret it so: the part you have not done is always the hard part. I think about it whenever I have “just about” completed a piece of work, with just one or two small steps to go. All the difficulties that are yet to come are still hidden from view, but I know they are lurking there.

How is life treating you today?

By Ruth Kimchi, Professor Emerita of Psychology, University of Haifa

I had the privilege to be a student of Danny Kahneman at the Hebrew University in my undergraduate and MA studies. Danny was a wonderful teacher, inspiring and challenging, and he had a profound influence on my academic life. I first fell in love with cognitive psychology when I participated in Danny’s Experimental Psychology class. It was a mandatory course in the second year of the undergraduate studies and the title did not hint, even in the least, at the instructive and enlightening lessons.

I also worked as Danny’s research assistant, mainly in the years he was working on his book Attention and Effort. We used to meet in his small office, which was crowded with books and the huge computer-output papers, discussing ideas, results of experiments, and so often, contemplating life. I still remember how he used to welcome me on the days we met, asking, “How is life treating you today?” It’s perhaps not surprising that somewhat later in his career, Danny studied happiness and well-being.

Danny, my teacher, I’ve learned a lot from you; lessons that accompanied me during my Ph.D. studies at Berkeley and in the many years of research and teaching.

With Barbara Tversky

Images: Feature image, courtesy of the Trustees of Princeton University; “Working,” courtesy of Richard Thaler; “With Amos Tversky,” “Moses,” and “With Barbara Tversky,” courtesy of Barbara Tversky; “With Avishai Henik,” courtesy of Avishai Henik; all other images courtesy of the Kahneman family. Used with permission. Not for reuse or distribution.

Disclosure: Barry Schwartz, Richard Thaler, and Angela Duckworth are members of Behavioral Scientist’s advisory board. Craig Fox and Katy Milkman lead organizations that have provided financial support to Behavioral Scientist. Advisors and organizational supporters do not play a role in the editorial decisions of the magazine.