Dan Ariely

Introduction

Dan Ariely (born April 29, 1967) is an Israeli-American psychologist and behavioral economist at Duke University, where he holds the James B. Duke Professorship of Psychology and Behavioral Economics. He studies the ways in which human choices depart systematically — and therefore predictably — from the assumptions of standard economic theory, a program summed up in the title of his best-known book, Predictably Irrational (2008). His research topics include the pull of "free," the small dishonesties that most people commit while continuing to see themselves as honest, and the role of meaning and effort in motivation. He founded the Center for Advanced Hindsight at Duke and has advised companies and public bodies on applying behavioral science. Since 2021, several of his papers have been retracted or questioned because other researchers found evidence that the underlying data had been fabricated. Ariely denies fabricating data; a Duke investigation that concluded in 2024 found, according to him, no evidence that he had knowingly used falsified data.

Early Life and Education

Ariely was born in New York City while his father was studying for an MBA at Columbia University. The family emigrated to Israel when he was three, and he grew up in Ramat Hasharon. In his final year of high school he was active in the Hanoar Haoved Vehalomed youth movement, and while preparing a ktovet esh — a fire inscription for a traditional nighttime ceremony — the flammable materials he was mixing exploded. He suffered third-degree burns over more than 70 percent of his body.

The years of hospitalization and painful dressing changes that followed shaped his research agenda. He noticed that nurses removed bandages as quickly as possible in the belief that this minimized suffering, and he suspected the opposite was true. That question led him to study how people experience and remember painful episodes, and eventually to the broader question of why human judgment about one's own experience goes wrong.

At Tel Aviv University he began in physics and mathematics, moved into philosophy and psychology, and finished a bachelor's degree in psychology in 1991. He then went to the University of North Carolina at Chapel Hill, earning a master's degree in cognitive psychology in 1994 and a doctorate in 1996. He completed a second doctorate, in business administration, at Duke University in 1998 — a step he has said he took at the urging of Daniel Kahneman; his advisers at Duke included James Bettman and John G. Lynch Jr.

Academic and Professional Career

Ariely taught at the Massachusetts Institute of Technology from 1998 to 2008, holding the Alfred P. Sloan Professorship of Behavioral Economics and working in part through the MIT Media Lab. In 2008 he returned to Duke as the James B. Duke Professor of Psychology and Behavioral Economics and established the Center for Advanced Hindsight, a laboratory devoted to decision making by physicians and patients, the psychology of money, cheating, and social justice.

Outside the university he has been a conspicuous public figure in behavioral science. He served as chief behavioral officer at the insurance company Lemonade, co-produced the 2015 documentary (Dis)Honesty: The Truth About Lies, and wrote the "Ask Ariely" advice column in The Wall Street Journal from June 2012 until September 2022. His life and his book Predictably Irrational inspired the NBC drama series The Irrational, which premiered in September 2023. In 2008 he shared an Ig Nobel Prize in Medicine with Rebecca Waber, Ziv Carmon, and Baba Shiv for work showing that a high-priced placebo is more effective than a low-priced one.

In 2006, while at the MIT Media Lab, Ariely ran experiments involving electric shocks with a research assistant who had not completed the required human-subjects training. MIT's ethics committee barred him from supervising data collection for a year. Ariely confirmed the sanction and said he had not known that the assistant lacked the one-hour online training.

Major Contributions to Psychology

Predictable irrationality in judgment and choice

Much of Ariely's early work asked whether preferences are as stable as economic theory assumes. In work with George Loewenstein and Drazen Prelec on "coherent arbitrariness," he showed that initial anchors — including arbitrarily generated ones such as the last digits of a social security number — can shift willingness to pay, and that these shifts persist because people treat their earlier choices as evidence of their own tastes. With Kristina Shampanier and Nina Mazar he documented the "zero price effect": the demand for a good jumps when its price falls to zero by an amount far larger than standard cost-benefit reasoning can explain, because free offers recruit an affective response that ordinary price comparisons do not. He also studied asymmetric dominance, showing that people seek subjective justification for choices by favoring options that dominate an available alternative.

Dishonesty and the fudge factor

Ariely's most influential line of research, developed with Nina Mazar and On Amir and published as "The Dishonesty of Honest People: A Theory of Self-Concept Maintenance," used tasks in which participants could surreptitiously overreport their own performance. The consistent finding was not that a few people cheat a great deal but that many people cheat a little: they take enough to gain, but stop short of the point at which they could no longer sustain a favorable self-image. Cheating did not rise as expected when the stakes rose or the chance of detection fell. Reminders of moral standards — including signing an honesty pledge at the top of a form rather than at the bottom — reduced it, while watching another person cheat increased it. He argued that dishonesty is governed less by a rational calculation of expected payoff than by the need to preserve a story about oneself.

Effort, meaning, and the IKEA effect

With Michael Norton and Daniel Mochon, Ariely showed that people value self-assembled products more highly than identical pre-assembled ones, an effect the authors named after a flat-pack furniture retailer. Related experiments on the "meaning of work" found that even trivial acknowledgment sustains effort, while having one's work ignored or destroyed in front of one causes people to stop. These studies supported his argument that motivation depends substantially on a sense of purpose and progress rather than on payment alone.

Procrastination and self-control

With Klaus Wertenbroch, Ariely published a widely cited study in 2002 on deadlines as a precommitment device, reporting that students performed better when they were given evenly spaced external deadlines than when they were free to set their own or faced only a final deadline. The paper has been heavily cited in discussions of self-control and in the productivity literature; it is also one of the studies whose data were later challenged.

Pain and medical decision making

Drawing on his own experience, Ariely conducted experiments on how people combine experiences over time, finding that retrospective evaluations of pain depend heavily on the change in intensity and on how an episode ends, rather than on total duration. This work fed into his later research on how patients and physicians make decisions under discomfort and uncertainty.

Major Publications

Predictably Irrational: The Hidden Forces That Shape Our Decisions (2008)
The Upside of Irrationality: The Unexpected Benefits of Defying Logic (2010)
The Honest Truth About Dishonesty: How We Lie to Everyone, Especially Ourselves (2012)
Payoff: The Hidden Logic That Shapes Our Motivations (2016)
Dollars and Sense: How We Misthink Money and How to Spend Smarter (2017), with Jeff Kreisler
Amazing Decisions: The Illustrated Guide to Improving Your Decision Making (2019)
Ariely, D., & Wertenbroch, K. (2002). Procrastination, deadlines, and performance: Self-control by precommitment. Psychological Science, 13, 219-224.
Ariely, D., Loewenstein, G., & Prelec, D. (2003). Coherent arbitrariness: Stable demand curves without stable preferences. Quarterly Journal of Economics, 118, 73-106.
Shampanier, K., Mazar, N., & Ariely, D. (2007). Zero as a special price: The true value of free products. Marketing Science, 26, 742-757.
Mazar, N., Amir, O., & Ariely, D. (2008). The dishonesty of honest people: A theory of self-concept maintenance. Journal of Marketing Research, 45, 633-644.
Norton, M. I., Mochon, D., & Ariely, D. (2011). The IKEA effect: When labor leads to love. Journal of Consumer Psychology, 21, 453-460.

Impact and Legacy

Ariely did more than almost anyone else to carry behavioral economics out of journals and into boardrooms, product design, and public policy. His framing of irrationality as systematic rather than random gave practitioners a usable design principle, and findings such as the zero-price effect and the honesty pledge have been applied in pricing, compliance, and organizational ethics. His books, TED talks, and newspaper column made him one of the most recognizable psychologists in the world, and the television series The Irrational carried his ideas into popular entertainment.

That reputation has been badly damaged by questions about his data. In August 2021 the blog Data Colada — Uri Simonsohn, Joe Simmons, and Leif Nelson — reported that the data in Study 3 of a 2012 Proceedings of the National Academy of Sciences paper by Lisa L. Shu, Nina Mazar, Francesca Gino, Ariely, and Max H. Bazerman, a field experiment at an auto insurance company, appeared to have been fabricated; spreadsheet metadata indicated that Ariely had created the file and was the last person to modify it. All five authors accepted that the data appeared fraudulent and asked for a retraction, which PNAS issued in September 2021. Ariely said the data had been collected, entered, merged, and anonymized by the insurance company before being sent to him, that he had no reason to suspect a problem, and that he would in future test incoming data for irregularities. In 2023 Data Colada reported that Study 1 of the same paper had also been altered and attributed that alteration to Gino, who has denied wrongdoing.

Ariely has maintained that he neither fabricated data nor knew that falsified data were being used. In 2024 he told reporters that after roughly three years Duke's investigation had concluded that the honesty-pledge data had been falsified but had found no evidence that he had used fake data knowingly. Duke declined to confirm or describe the outcome, citing confidentiality, so his account rests on his own statement. Other episodes have compounded the damage: in 2021 Psychological Science attached an expression of concern to a 2004 paper by James Heyman and Ariely, although Gregory Francis later showed that the anomaly could be a reporting error in which t statistics were printed as F statistics, which would not overturn the findings. In 2022 the Israeli television program Hamakor questioned whether some studies had been conducted at all; UCLA said the "Ten Commandments" study did not take place there and Aimee Drolet Rossi said she had no memory of running it, while Ariely told The New Yorker that the surveys were collected at UCLA but processed by an assistant at MIT. A later analysis commissioned by the American Marketing Association found the reported results largely reproducible from the data the authors supplied.

The questions are still open. In 2026 Psychological Science published a replication by Kyle Hyndman and Alberto Bisin of Study 2 of the 2002 procrastination paper; their new data showed negligible effects of deadline changes on all three performance measures. In August 2026 Data Colada reported duplicated observations and other patterns in the original spreadsheets and concluded that the Study 2 data had been tampered with or fabricated. Wertenbroch said he had never had access to the data and asked the journal to retract the paper. Ariely did not respond to Data Colada's enquiries but wrote publicly that the data contain serious anomalies, that the records and memories available after more than two decades are insufficient to answer the questions raised, and that he would cooperate with the journal's review. Defenders of his broader body of work note that several of the phenomena he popularized — the pull of free, the effectiveness of honesty pledges — have independent support from other laboratories, and that the individual findings should be judged on their own evidence. Critics reply that a program of research in which fabricated data appear repeatedly in different papers and across two decades cannot be assessed finding by finding.

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References

Ariely, D. (2008). Predictably Irrational. Harper.