Joachim Krueger

Introduction

Joachim I. Krueger is a German-born social psychologist at Brown University who studies what he calls inductive reasoning in social context: how people draw conclusions about other people, about groups, and about themselves from limited evidence. He is best known for two research programs that pull in opposite directions. The first concerns social projection — the tendency to assume that others think and act as one does — and self-enhancement, the tendency to rate oneself as better than average, and the way the two combine when people decide whether to cooperate. The second, and the reason he is known outside his subfield, is methodological: over two decades he has been one of the most articulate defenders of null hypothesis significance testing and one of the more pointed skeptics about the replication crisis. The title of his Brown research statement is a fair summary of his position: "The replication crisis. What crisis?"

Early Life and Education

Krueger was born and educated in Germany, completing a Diplom — the German equivalent of a master's degree — at the University of Bielefeld, with minors in sociology, education, and business management. Before and immediately after that degree he worked in applied settings unusual for an academic psychologist: at the psychological services department of the chemical firm Hüls, and in the psychological assessment office of the Bielefeld labor office. He also took a primary certificate in Rational Emotive Therapy, an episode he records in his own curriculum vitae with the note that the training involved a mock therapy session in which Albert Ellis asked him to treat Ellis's shyness with girls.

A Fulbright scholarship took him to the United States in 1983. He earned an M.A. in 1984 and a Ph.D. in 1988, both in psychology at the University of Oregon, where he has said he had a "glorious experience." He then spent three years as a postdoctoral researcher at the Max Planck Institute for Human Development and Education in Berlin before joining Brown in 1991, where he has remained.

Academic and Professional Career

At Brown, Krueger is Professor of Cognitive, Linguistic, and Psychological Sciences, with adjunct appointments in the Department of Philosophy and the Center for Latin American and Caribbean Studies, and a standing appointment at the Instituto de Empresa in Madrid. He has held visiting professorships at Heidelberg, Marburg, Graz, Bergamo, and the Max Planck Institute for Human Development, and has served on the scientific advisory board of that institute and on the advisory board of a research training group at Philipps University Marburg. In 2022 he was a fellow at the Center for Advanced Studies at Ludwig Maximilian University in Munich.

He received the Humboldt Research Prize in 2008, renewed in 2016. Between 2000 and 2002 he served on the American Psychological Society's Task Force on Self-esteem, an appointment that produced one of his most cited papers. He is the author, co-author, or editor of seven books and more than a hundred articles and chapters, and in 2023 colleagues honored him with a Festschrift, Inductive Reasoning in Social Contexts, published in Swiss Psychology Open.

His teaching covers an unusually wide span for a social psychologist: a laboratory course in social cognition, a core doctoral course in social psychology, and lecture courses on happiness and on creativity, the last of which reflects a long-running interest in topics that sit uneasily with positivism. He writes a blog at Psychology Today and has published free books on happiness and on rationality.

Major Contributions to Psychology

Social Projection and Self-Enhancement

Krueger's central observation is that people use themselves as the primary datum when estimating what others are like — a process he calls social projection — and that this heuristic is not merely a bias but often makes social perception more accurate, because on most dimensions most people really are similar. His 1997 review with Russell Clement laid out the case, including the finding that members of numerical majorities and minorities project differently.

The harder problem is that projection and self-enhancement point in opposite directions: one says "others are like me," the other says "I am better than others." Krueger's work with collaborators argues these are not competing motives in a hydraulic trade-off but processes that can operate together, with projection sometimes serving to blunt a threat to the need to feel excellent. This work connects directly to the literature on social identity and intergroup perception.

The Better-Than-Average Effect Is Partly Arithmetic

With Richard Mueller, Krueger published a 2002 paper in Journal of Personality and Social Psychology with the title "Unskilled, unaware, or both?" The paper asked whether the better-than-average effect — the standard finding that most people rate themselves above the median on most traits — is a genuine motivational bias or an artifact. Using a heuristic-plus-regression model, they showed that a large part of the effect follows from how people use the self as an anchor and regress imperfectly from it, plus the ordinary statistical properties of self-report scales on hard tasks. The result was deflationary: a phenomenon usually explained by self-esteem maintenance could be reproduced by a model that contains no motivation at all. This was closely related to, and published in the same year as, the parallel work on the Dunning-Kruger effect by David Dunning and Justin Kruger, and it remains one of the standard methodological cautions in self-perception research.

Cooperation Without Prosocial Motives

Krueger has argued that cooperation in one-shot social dilemmas, such as the prisoner's dilemma or the volunteer's dilemma, can be explained without positing a prosocial preference. If people project — if they assume others will do what they would do — then the expectation of reciprocity does the work that a social preference is otherwise invoked to explain. This "K-index" approach replaces altruism with Bayesian inference, and it has been applied to the volunteer's dilemma, the question of why anyone volunteers when one volunteer is enough and everyone would prefer that someone else did it.

A Defense of Significance Testing

Krueger's 2001 American Psychologist review, "Null hypothesis significance testing: On the survival of a flawed method," surveyed the long campaign against the p-value and the arguments for keeping it, and concluded that both critics and defenders rely on Bayesian assumptions they have not made explicit; once those are stated, the real question is replicability rather than logic. He returned to the question in 2018 with Patrick Heck, using simulation to argue that p-values predict posterior probabilities well, that low p-values do support inductive inference, and that p-values predict replicability better than confidence intervals do.

Major Publications

  • Krueger, J., & Clement, R. W. (1997). Estimates of social consensus by majorities and minorities: The case for social projection. Personality and Social Psychology Review, 1(4), 299–313.
  • Krueger, J. (2000). Distributive judgments under uncertainty: Paccioli's game revisited. Journal of Experimental Psychology: General, 129(4), 546–558.
  • Krueger, J. (2001). Null hypothesis significance testing: On the survival of a flawed method. American Psychologist, 56(1), 16–26.
  • Krueger, J., & Mueller, R. A. (2002). Unskilled, unaware, or both? The better-than-average heuristic and statistical regression predict errors in estimates of own performance. Journal of Personality and Social Psychology, 82(2), 180–188.
  • Baumeister, R. F., Campbell, J. D., Krueger, J. I., & Vohs, K. D. (2003). Does high self-esteem cause better performance, interpersonal success, happiness, or healthier lifestyles? Psychological Science in the Public Interest, 4(1), 1–44.
  • Krueger, J. I. (Ed.). The Self in Social Judgment. Psychology Press.
  • Krueger, J. I. (Ed.). Rationality and Social Responsibility: Essays in Honor of Robyn Dawes. Psychology Press.
  • Krueger, J. I., & Heck, P. R. (2018). Testing significance testing. Collabra: Psychology, 4(1), 11.

Impact and Legacy

Krueger's methodological caution has shaped how self-perception research is read. After the 2002 paper, it is no longer acceptable to treat a better-than-average finding as straightforward evidence of motivated self-enhancement; reviewers now reasonably ask whether the arithmetic alone would have produced it. His advisory work on the self-esteem task force also had public consequences: the 2003 review concluded that high self-esteem does not cause better school or job performance and is not the protective factor it was widely assumed to be, a conclusion that helped end a decade of self-esteem-based educational programs.

The criticisms of his positions are as developed as the positions themselves, and they are worth stating plainly because Krueger is, on these questions, a minority voice.

On significance testing, the standard reply is that his defense answers a different question from the one critics are asking. The simulation results in the 2018 paper show that p-values behave reasonably when the model is well specified and power is adequate; the reform literature's complaint is precisely that in ordinary practice power is low, analyses are flexible, and publication is selective. The American Statistical Association's 2016 statement, and the extensive commentary around it, made the point that p-values are not the problem in themselves but that their use as a bright line between "real" and "null" is. Critics also note that the claim that p-values predict replicability better than confidence intervals is close to vacuous, since a confidence interval and the corresponding p-value are functions of the same data and the same model, so the comparison turns entirely on how the simulation is set up.

On the replication crisis, his rhetorical question has drawn a sharper response. Skepticism about the crisis is often read as a defense of existing practice by a researcher with no stake in changing it, and several of the replication projects he has questioned — including the large multi-lab attempts — reported failure rates that are difficult to explain away as statistical misunderstanding. His position requires that most published effects be approximately real, which is exactly the proposition the replication literature put in doubt; asserting it does not settle it.

The self-esteem review drew its own reply. Critics argued that the task force read the correlational literature selectively and that measures of specific self-concept predict outcomes better than global self-esteem scales do, so the conclusion should have been about the construct's measurement rather than about the construct. A related tension runs through Krueger's own work on the better-than-average effect: having supplied one of the strongest artifact accounts of it, he has resisted the full deflation that account implies, arguing instead that the heuristic and the motive both operate. Critics on the other side note that the regression model cannot explain the effect on easy tasks, where most people really are above average, and that the two accounts have not been cleanly separated.

What is not disputed is his role as the field's most literate internal skeptic. He asks, repeatedly and with unusual precision, whether the phenomena social psychology reports are phenomena at all, or artifacts of the instruments used to find them — and he asks it of his own findings first.

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References

  • Krueger, J., & Clement, R. W. (1994). The truly false consensus effect. Journal of Personality and Social Psychology, 67(4), 596-610.

Last updated: 2026-10-20

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