Experimental math (XKCD)

The Unreasonable Effectiveness of Mathematics

 https://xkcd.com/3180/

 

Nottingham's Centre for Decision Research and Experimental Economics celebrates its 25th anniversary

 In September, Nottingham's productive center for experimental economics celebrated a quarter century since it's founding: 

 CeDEx 25th Anniversary Workshop .

I just saw the announcement now, but maybe that's a sign of how successfully experimental economics has become established in the profession, over the last century and around the world.

 For some early history, see e.g. 

Roth, Alvin E. "The early history of experimental economics." Journal of the History of Economic Thought 15.2 (1993): 184-209.

 

Judd Kessler: the most helpful advice I ever got (YouTube short video)

 I was charmed by this very short video featuring Judd Kessler (and I'm very grateful to whoever gave him that advice):

 

 

https://youtube.com/shorts/zBTlYwvYE2M?si=q6_vRIflWvAmMDYb 

 

 

 

 

You can see his new book, Lucky By Design in the background 

“Lucky by Design is that rarest of things: an economics PAGE-TURNER.” —Lin-Manuel Miranda 

European Economic Review Summer School in Experimental and Behavioral Economics, June 1-4, 2026.

 

 It's never too late to learn about experiments:

3rd European Economic Review Summer School  in Experimental and Behavioral Economics

The European Economic Review is pleased to announce their third Summer School in Experimental and Behavioral Economics to be held at ISEG in Lisbon from June 1 to June 4, 2026. The School will feature lectures by leading researchers in state-of-the-art topics in experimental and behavioral economics in addition to a research workshop. Throughout the School the students will be able to present their own research in poster sessions and receive feedback from leading faculty and fellow participants. 

The 3rd European Economic Review Summer School is very privileged to feature lectures by leading figures such as Isabelle Brocas (University of Southern California), Juan D. Carrillo (University of Southern California), Vincent Crawford (Oxford University and University of California at San Diego), Michalis Drouvelis (University of Birmingham), Ernst Fehr (University of Zurich) and David Levine (Royal Holloway University of London). The goal of the School is to deepen attendants’ understanding and knowledge of recent advances in the field of Experimental and Behavioral Economics. The topics taught will cover a broad range of methodologies such as theory, laboratory and field experiments, as well as applications. The School will provide a unique environment where students can expand their knowledge on topical research issues and engage with leading figures in the field. Scholars who have been admitted to the School will be taught the following subjects:

• decision-making and its biological causal processes (Isabelle Brocas)

• decision-making in children and adolescents (Juan D. Carrillo) 

• behavioral game theory and topics in behavioral decision theory (Vincent Crawford)

• experimental games in the lab; emotions and human cooperation (Michalis Drouvelis)

• economics of social preferences; product obfuscation in markets (Ernst Fehr)

• quantitative behavioral theories of long term play in experiments (David Levine)

Further details on the content of the lectures, as well as background material, will be uploaded gradually in the Program of the School. 

The Summer School invites applications from Ph.D and MSc students in Economics, Business, Psychology, Behavioral Science, Political Science and related fields from all over the world. Faculty and professionals are also welcome. To apply to the School, please submit a CV using our Application Form. The deadline for applications is January 31, 2026. Decisions will be sent to applicants by February 14, 2026. 

Experimental economics at the University of Pittsburgh

 I recently had the opportunity to visit my old haunts at the University of Pittsburgh, and took part in a reopening and re-dedication of the famous experimental economics lab there. Here's the announcement:

 PEEL is officially back open after renovations

The Pittsburgh Experimental Economics Laboratory (PEEL) celebrated its grand reopening last week following substantial renovation. Led by PEEL Director Lise Vesterlund, the renovations allow Pitt to continue to lead as one of the preeminent experimental economics research universities in the country.

Alvin Roth, winner of the 2012 Nobel Memorial Prize in Economics, was on site to celebrate the event. Roth, who was the Andrew W. Mellon Professor of Economics at Pitt through the 1980s and 90s and is now a professor at Stanford University, founded the lab in 1988 alongside then-Pitt Professor John Kagel.  His original research at PEEL led to his Nobel Prize for market design and to his design of the National Residency Matching Program (NRMP) and the New England Program for Kidney Exchange.  

“Experiments are very powerful, and I think this [lab] is a huge advantage,” Roth said. “For a long time, economists thought of data as something that governments collected […] but when you do experiments, you can carefully control for what you think are relevant differences and understand causes much better.” 

 

 Vesterlund, who has held the Mellon chair in economics since 2007, has conducted countless experiments in the lab. Particularly influential has been her research assessing the impact of work assignment on gender differences in advancement, research that lead to her award-winning co-authored book The No Club: Putting a Stop to Women's Dead-End Work.  

Vesterlund says a well-functioning lab is the foundation for Pitt’s strong economics department. “PEEL is a world-renowned experimental economics laboratory.  It has been the home to countless seminal research findings. Findings that seeded fields in the profession and improved the way we design markets and organizations. Few institutions can maintain a well-functioning lab, and PEEL has been essential in drawing an exceptionally strong group of scholars to Pitt. The renovation will ensure that the University of Pittsburgh continues to be the center for cutting-edge research in experimental economics.” 

The ceremony included opening remarks from Dean Adam Leibovich before Vesterlund and Roth cut the ribbon, formally re-opening the lab. The renovated lab comprises 40 computer kiosks, where participants can engage with state-of-the-art research software and make choices that inform us about human decision-making.  

To learn more about research being conducted in the lab, you can visit the PEEL website.

 

Experiments and behavioral market design at Pitt (tomorrow)

 I'm flying  back to my old haunts in Pittsburgh today, for (among other things) two events at the University of Pittsburgh tomorrow:

 October 17, 2025 PEEL Reopening Ceremony with Professor Vesterlund & Professor Roth

"The History of PEEL: The Pittsburgh Experimental Economics Laboratory (PEEL) was founded by John Kagel and Alvin Roth, a Nobel Laureate in Economics. Since its inception, PEEL has served as a hub for pioneering research in experimental economics. Notably, the lab contributed to foundational work on market design, which played a significant role in Roth’s Nobel Prize-winning contributions. Over the decades, PEEL has maintained its reputation as a center of excellence, attracting top scholars and fostering innovation in economic research. +

 

October 17, 2025 BEDI Workshop (Behavioral Economics and Design Initiative)

BEDI Workshop - Friday, October 17th, 2025

Breakfast | 8:15 am – 8:45 am
Wesley W. Posvar Hall, 4130, 230 S Bouquet St, Pittsburgh, PA 15213 

Conference Welcome | 8:45 am – 9:00 am
Lise Vesterlund, BEDI Director, Andrew W. Mellon Professor, University of Pittsburgh

Session 1 | 9:00 am – 10:40 am
Erina Ytsma– Assistant Professor, Carnegie Mellon University, “Gender Differences in the
Response to Incentives: Evidence from Academia”
Stephanie Wang – Professor, University of Pittsburgh
Claire Duquennois – Assistant Professor, University of Pittsburgh, “Minority athletic performance,
racial attitudes, and racial hate”
Jonathan Woon – Professor & Associate Dean, University of Pittsburgh, “The Epistemology of
Justice: Awareness and Institutional Choice”

Refreshment Break | 10:40 am – 11:10 am

Session 2 | 11:10 am – 12:00 pm
Jenny Chang – Graduate Student, Carnegie Mellon University, “When Women Self-Promote:
Evidence on Beliefs and Downstream Consequences”
Aden Halpern – Graduate Student, University of Pittsburgh 

Brandon Williams – Graduate Student, University of Pittsburgh
Dhwani Yagnaraman – Graduate Student, Carnegie Mellon University, “Crowd-in and crowd-out of
climate policies”
Aaron Balleisen– Graduate Student, Carnegie Mellon University, “Cheap Talk and Pluralistic
Ignorance”

Lunch | 12:00 am – 1:15 pm

Session 3 | 1:15 pm – 2:30 pm
Osea Giuntella – Associate Professor, University of Pittsburgh, “Beliefs, Resilience, and Leadership: Evaluating Trauma-Informed Training”
John Conlon – Assistant Professor, Carnegie Mellon University, “Memory Rehearsal and Belief Biases”
Alex Chan – Professor, Harvard University, “Preference for Explainable AI”

PEEL Re-Opening + Refreshment Break | 2:30 pm to 3:30 pm

Session 4 | 3:30 pm – 4:45 pm
Alistair Wilson – Professor, University of Pittsburgh, “Veto Delegation: A Mechanism that works! (Kinda)”
Yucheng Liang – Assistant Professor, Carnegie Mellon University, “Asking the Right Questions: Information Acquisition for Choices under Risk”
Muriel Niederle - Professor, Stanford University

 

Investigating human and LLM psychology by prompting LLMs to play experimental economics games: Xie, Mei, Yuan, and Jackson in PNAS

 The great science fiction writer of my youth was Isaac Asimov, who not only wrote space opera (The Foundation Trilogy), but also wrote about intelligent robots, i.e. about robots with artificial general intelligence.  So, like you and me, they had complicated psychological lives, and one of the main characters in these stories was the robopsychologist  Dr. Susan Calvin (see e.g. the short story collection I, Robot, and also several of the robot novels).

I'm reminded of this by the several papers now reporting how large language models respond when asked to play games that have been used to study human behavior.  Those papers are framed as using LLMs to learn about the human behavior on which they were trained. But they can also be read as telling us about the 'psychology' of LLMs. Here's a good one from the PNAS. 

Xie, Yutong, Qiaozhu Mei, Walter Yuan, and Matthew O. Jackson. "Using large language models to categorize strategic situations and decipher motivations behind human behaviors." Proceedings of the National Academy of Sciences 122, no. 35 (2025): e2512075122. 

Abstract: By varying prompts to a large language model, we can elicit the full range of human behaviors in a variety of different scenarios in classic economic games. By analyzing which prompts elicit which behaviors, we can categorize and compare different strategic situations, which can also help provide insight into what different economic scenarios might induce people to think about. We discuss how this provides a step toward a nonstandard method of inferring (deciphering) the motivations behind the human behaviors. We also show how this deciphering process can be used to categorize differences in the behavioral tendencies of different populations. 

 

The effect of biological nudges may (also) have been overstated

 There have been a number of recent studies suggesting that the effectiveness of psychological "nudges" may have been substantially overstated. Here's a paper saying something similar about snorting testosterone:

 Dreber, Anna, Magnus Johannesson, Gideon Nave, Coren L. Apicella, Shawn N. Geniole, Taisuke Imai, Erik L. Knight et al. "Investigating the effects of single-dose intranasal testosterone on economic preferences in a large randomized trial of men." Proceedings of the National Academy of Sciences 122, no. 39 (2025): e2508519122. 

Abstract: "There is conflicting evidence on whether testosterone affects economic preferences such  as risk taking, fairness, and altruism, with most evidence coming from correlational  studies or small testosterone administration studies. To credibly test this hypothesis,  we conducted a large-scale, preregistered, double-blind randomized controlled trial with  1,000 male participants—10 to 20 times larger than typical prior studies. Participants  were randomly allocated to receive a single dose of either placebo or intranasal testosterone, and carried out a series of economic tasks capturing social preferences, competitiveness, and risk preferences. We find no evidence of a treatment effect for any of  our nine primary outcome measures, and no strong evidence of an association between  basal salivary testosterone and economic preferences within men. These results fail to  conceptually replicate previous high-impact publications reporting positive findings in  smaller samples, calling into question the idea that short-term testosterone fluctuations  are important drivers of men’s economic preferences. Our results do not rule out the  possibility that different effects might emerge under alternative dosages, administration  protocols, or task timings, or that behavioral effects differ between men and women. The  potential for developmental or long-term effects of testosterone also remains an open  question for future research, though such effects are ethically challenging to investigate  experimentally in humans." 

 

"The number  of participants in the studies reporting any statistically significant effects has ranged from N = 24 ( 18 ) to N = 118 ( 14 ). It is well  known that small, underpowered studies increase the risk that findings reported as statistically significant are false positives..."

...

"We fail to find evidence of a treatment effect of a single-dose of 
intranasal testosterone on any of our eight primary outcome measures or the hypothesized interaction effect for the ninth primary outcome measure. The 99.5% CI can be used to interpret which  effect sizes in the hypothesized direction we find strong evidence  against, see Figs. 1 – 3 . For our eight main effects primary hypotheses, we find strong evidence against effect sizes between about 0.15 Cohen’s d units (Investor Value and Loss Aversion) and 0.26 Cohen’s d units (Risk Aversion), which are considered small effect  sizes. We thus find strong evidence against the hypothesis that  single-dose intranasal testosterone administration has important  effects on economic preferences or behavior in men for all outcome measures in our study.

...

" Our study can be considered a highly powered conceptual replication of several previous results reported in high-impact journals, with a 10 to 20 times larger sample size than most previous  randomized controlled studies. However, our study does not constitute a direct replication of any specific previous study as we did  not base our design on one individual previous study ( 66 ). Our  study fails to conceptually replicate the following previous findings  about treatment effects of testosterone: that testosterone increases  offers in the ultimatum game ( 13 ); that testosterone decreases  offers in the ultimatum game ( 12 ); that testosterone decreases trust  in the trust game ( 16 ); that testosterone increases trustworthiness  (backtransfers) in the trust game ( 16 ), and that testosterone  increases risk taking (17). We furthermore fail to conceptually replicate previous correlational results that testosterone is positively correlated with economic risk-taking ( 26 , 29 , 67 ), that  testosterone is positively correlated with generosity in the dictator  game ( 30 ), and that testosterone is positively correlated with the  rejection of unfair offers in the ultimatum game ( 25 )."

Explaining economics can change the evaluation of policies, by Elias, Lacetera and Macis

 Perhaps economists should get involved in the discussion of public policies during political campaigns...

Is the Price Right? The Role of Economic Trade-Offs in Explaining Reactions to Price Surges
Julio Elías, Nicola Lacetera , Mario Macis    Management Science
Published Online:4 Jul 2025https://doi.org/10.1287/mnsc.2024.04555 

Abstract: Public authorities often introduce price controls following price surges, potentially causing inefficiencies and exacerbating shortages. A survey experiment with 7,612 Canadian and U.S. respondents shows that unregulated price surges raise moral objections and widespread disapproval. However, acceptance increases and demand for regulation declines when participants are prompted to consider economic trade-offs between controlled and unregulated prices, whereby incentives from higher prices lead to additional supply and enhance access to goods. Moreover, highlighting these trade-offs reduces polarization in moral judgments between supporters and opponents of unregulated pricing. Textual analysis of responses to open-ended questions provides further insights into our findings, and an incentivized donation task demonstrates consistency between stated preferences and real-stakes behavior. Although economic trade-offs do influence public support for price control policies, the evidence indicates that even when the potential gains in economic efficiency from unregulated prices are explicit, a significant divide persists between the utilitarian views that standard economic thinking implies and the nonutilitarian values held by the general population.

 

"Overall, therefore, we document widespread opposition to sudden price surges, motivated in large part by moral and ideological considerations. However, explicitly describing possible economic trade-offs between policy regimes does affect people’s reactions by making them more open to letting prices move freely. This result suggests that people do not immediately consider efficiency or equilibrium considerations when reacting to and expressing a judgment about price surges. When considerations about economic efficiency are missing, moral reactions are highly polarized; when economic trade-offs are explicit, views tend to converge. However, the fact that most respondents still support price control policies in this case suggests that this position derives from normative concerns and not necessarily from a lack of consideration for equilibrium effects and efficiency implications."

Experimental and behavioral econ at Stanford in August (registration open)

 Here is the program and links to register for the Stanford Experimental Economics session at SITE this summer: 

Session 13: Experimental Economics  Wed, Aug 20 2025, 8:00am - Thu, Aug 21 2025, 5:00pm PDT

Organized by
Christine Exley, University of Michigan
Muriel Niederle, Stanford University
Kirby Nielsen, California Institute of Technology
Al Roth, Stanford University
Lise Vesterlund, University of Pittsburgh

###########

And here's an announcement of a workshop that will immediately follow that session:

On August 21-23 Stanford will host the third instance of the Graduate Student Boot Camp in Behavioral Public Economics. The camp is organized by Doug Bernheim, Ben Lockwood, and Dmitry Taubinsky. It will feature instructional sessions from each of them, as well as sessions from four external speakers: Matthew Gentzkow, Botond Kőszegi, Olivia Mitchell, and Matthew Notowidigdo.

We would also like to invite other young scholars—graduate students, postdocs and assistant professors—to audit the boot camp. We will not be able to provide accommodations or cover travel expenses, but we welcome participation in our lectures/discussions and meals.  If you are a young scholar interested in attending some or all of the camp, please indicate your interest (and which sessions you would be able to attend, so that we can gauge attendance and our capacity constraints) via this form: https://forms.gle/dNBWgkrUXtYXgnMT9. We are aiming for 10-15 young scholars.

If you are interested in the content covered in previous instances of the boot camp, you can find additional information here and here.

All best,
Doug, Dmitry, and Ben

Congratulations to ESA award winners

 An email from the Economic Science Association (ESA) announces these new Fellows and award winners:

We are delighted to announce the recipients of the 2025 ESA Awards and the newest Fellows of the Economic Science Association. These awards recognize those who have made outstanding contributions to our field through research, service, mentoring, and leadership:

 

2025 ESA Distinguished Service Award
This award honours those who have played an exceptional role in the administration and growth of the ESA over the course of their careers. In 2025, we are proud to recognize two extraordinary recipients:

 

Professor Yan Chen
Professor Chen served as ESA President from 2015–2017. She established our mentoring program and served as the Director of the ESA Mentoring Program, a role she held until 2024. Through her efforts, hundreds of early career researchers have benefited from mentorship panels, helping to shape the next generation of experimental economists.

Professor Catherine Eckel
Professor Eckel served as ESA President from 2017–2019. Among her many contributions, she played a foundational role in establishing our ethics program, becoming ESA’s first Ethics Officer. She has been a dedicated mentor and advocate for junior scholars. Her leadership has been instrumental in making ESA a more inclusive and welcoming community for researchers at all stages of their careers.

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2025 ESA Young Scholar Prize
This prize recognizes a young scholar whose work has made a significant methodological contribution to experimental economics. Candidates must either be under the age of 40, hold an untenured position, or be within 10 years of completing graduate school. We are thrilled to announce the 2025 recipient:

Professor Christine Exley
Professor Exley is recognized for her research on motivated reasoning, charitable giving, and gender. Her work stands out for its innovative experimental designs, pushing the boundaries of how we study behaviour in complex social contexts.

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 2025 ESA Prize for Exceptional Achievement
This award honours a researcher who has overcome unusually challenging circumstances to make impactful contributions to experimental economics. We are very pleased to announce that the 2025 award goes to:

Professor Erin Krupka

Professor Krupka is widely known for her impressive work on social norms, including the development of incentivized norm elicitation techniques that have become a cornerstone in the field.

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2025 ESA Fellows
The designation of ESA fellow is intended to recognize the lifetime contributions of ESA members who have advanced the frontier of knowledge in economics through the use of laboratory and/or field experiments. The designation of an individual as an ESA fellow is intended as a permanent recognition of their contribution to experimental science and to economics.

We are delighted to welcome the following distinguished Professors as the 2025 ESA Fellows:

• Mark Isaac
• Rosemarie Nagel
• Robert Sugden
• Lise Vesterlund
• James Walker

Their body of work has significantly shaped experimental economics and will continue to inspire researchers across generations.

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The awardees and Fellows were selected by the 2025 ESA’s Awards and Fellows Committee. We extend our thanks to everyone who submitted nominations this year and encourage all ESA members to consider nominating deserving individuals for future awards and fellowships.

Please join me in congratulating this year’s outstanding scholars!

Lata Gangadharan (President, ESA)