More than two decades ago, Adam Riess’s Nobel Prize-winning work fundamentally changed our understanding of the universe. His new work is reshaping cosmology for a second time.

• RESOURCES:
  • Adam Riess, astrophysicist at Johns Hopkins University.

• SOURCES:
  • "The Nobel Prize Winner Who Thinks We Have the Universe All Wrong," by Ross Andersen (The Atlantic, 2025).
  • "The answer to life, the universe and everything might be 73. Or 67," by Hannah Devlin (The Guardian, 2018).
  • "Adam G. Riess Nobel Prize Lecture," (The Nobel Foundation, 2011).
  • "Breakthroughs 1998," by Floyd Bloom (Science, 1998).
  • "Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant," by Adam Riess, Alexei Filippenko, Peter Challis, Alejandro Clocchiatti, Alan Diercks, Peter Garnavich, Ron Gilliland, Craig Hogan, Saurabh Jha, Robert Kirshner, Bruno Leibundgut, Mark Phillips, David Reiss, Brian Schmidt, Robert Schommer, Chris Smith, Jason Spyromilio, Christopher Stubbs, Nicholas Suntzeff, and John Tonry (The Astronomical Journal, 1998).
  • "1912: Henrietta Leavitt Discovers the Distance Key," (Carnegie Institution for Science).

Uri Simonsohn is a behavioral science professor who wants to improve standards in his field — so he’s made a sideline of investigating fraudulent academic research. He tells Steve Levitt, who's spent plenty of time rooting out cheaters in other fields, how he does it.

• SOURCES:
  • Uri Simonsohn, professor of behavioral science at Esade Business School.

• RESOURCES:
  • "Gino v. President and Fellows of Harvard College," (Court Listener, 2025).
  • "Statement from Dan Ariely," (2024).
  • "Data Falsificada (Part 4): 'Forgetting The Words,'" by Uri Simonsohn, Leif Nelson, and Joe Simmons (Data Colada, 2023).
  • "They Studied Dishonesty. Was Their Work a Lie?" by Gideon Lewis-Kraus (The New Yorker, 2023).
  • "Evidence of Fraud in an Influential Field Experiment About Dishonesty," by Uri Simonsohn, Leif Nelson, and Joe Simmons (Data Colada, 2023).
  • "Signing at the beginning makes ethics salient anddecreases dishonest self-reports in comparison tosigning at the end," by Lisa Shu, Nina Mazar, Francesca Gino, Dan Ariely, and Max Bazerman (PNAS, 2021).
  • "Power Posing: Reassessing The Evidence Behind The Most Popular TED Talk," by Uri Simonsohn and Joe Simmons (Data Colada, 2015).
  • "Your Body Language May Shape Who You Are," by Amy Cuddy (TED, 2012).
  • "Daily Horizons: Evidence of Narrow Bracketing in Judgment from 10 Years of MBA-Admission Interviews," by Uri Simohnson and Francesa Gino (Psychological Science, 2012).
  • "Spurious? Name similarity effects (implicit egotism) in marriage, job, and moving decisions," by Uri Simohnson (Journal of Personality and Social Psychology, 2011).
  • "False-Positive Psychology: Undisclosed Flexibility in Data Collection and Analysis Allows Presenting Anything as Significant," by Joe Simmons, Leif Nelson, and Uri Simohnson (Psychological Science, 2011).

• EXTRAS:
  • "Will We Solve the Climate Problem?" by People I (Mostly) Admire (2025).
  • "Why Is There So Much Fraud in Academia?" by Freakonomics Radio (2024).
  • "When I'm Sixty Four," by The Beatles (1967).

Former U.S. Secretary of Education, 3x3 basketball champion, and leader of an anti-gun violence organization are all on Arne’s resume. He’s also Steve’s neighbor. The two talk about teachers caught cheating in Chicago public schools and Steve shares a story he’s never told Arne, about a defining moment in the educator’s life.

• SOURCES:
  • Arne Duncan, the 9th U.S. Secretary of Education; founder of C.R.E.D.; former head of Chicago Public Schools; and former professional basketball player.

• RESOURCES:
  • How Schools Work, by Arne Duncan (2018).
  • "Benji," (ESPN's 30 for 30, 2012).

• EXTRAS:
  • Chicago C.R.E.D.

Kate Marvel spends her days playing with climate models, which she says are “like a very expensive version of The Sims.” As a physicist she gets tired of being asked to weigh in on economics, geopolitics, and despair — but she still defends the right of scientists to have strong feelings about the planet.

• SOURCES:
  • Kate Marvel, climate scientist and science writer.

• RESOURCES:
  • Human Nature: Nine Ways to Feel About Our Changing Planet, by Kate Marvel (2025).
  • "Are Americans Concerned About Global Warming?" (Gallup, 2024).
  • "Can clouds buy us more time to solve climate change?" by Kate Marvel (TED, 2017).
  • SuperFreakonomics: Global Cooling, Patriotic Prostitutes, and Why Suicide Bombers Should Buy Life Insurance, by Stephen Dubner and Steve Levitt (2011).
  • "Global Warming’s Six Americas," (Yale Program on Climate Change Communication).
  • "Fred Rogers: Look for the Helpers."

Twenty years ago, before the Freakonomics book tour, Bill McGowan taught Steve Levitt to speak in public. In his new book he tries to teach everyone else.

• SOURCES:
  • Bill McGowan, founder and C.E.O. of Clarity Media Group.

• RESOURCES:
  • Speak, Memorably: The Art of Captivating an Audience, by Bill McGowan (2025).
  • "Sheryl Sandberg Gives UC Berkeley Commencement Keynote Speech," (UC Berkeley, 2016).
  • "Our failing schools. Enough is enough!" by Geoffrey Canada (TED, 2013).

• EXTRAS:
  • "The Power of a Bad Example – A Field Experiment In Household Garbage Disposal," by Robert Dur and Ben Vollaard (Tilburg Law and Economics Center, 2013).
  • "Unit pricing of municipal solid waste and illegal dumping: an empirical analysis of Korean experience," by Geum-Soo Kim, Young-Jae Chang and David Kelleher (Environmental Economics and Policy Studies, 2008).
  • "Garbage, Recycling, and Illicit Burning or Dumping," by Don Fullerton and Thomas Kinnaman (Journal of Environmental Economics and Management, 2002).

Former professional poker player Annie Duke wrote a book about Steve’s favorite subject: quitting. They talk about why quitting is so hard, how to do it sooner, and why we feel shame when we do something that’s good for us.

• SOURCES:
  • Annie Duke, author and former professional poker player.

• RESOURCES:
  • Quit: The Power of Knowing When to Walk Away, by Annie Duke (2022).
  • "Heads or Tails: The Impact of a Coin Toss on Major Life Decisions and Subsequent Happiness," by Steven Levitt (NBER Working Papers, 2016).
  • Superforecasting: The Art and Science of Prediction, by Philip E. Tetlock and Dan Gardner (2015).
  • "Knee-Deep in the Big Muddy: A Study of Escalating Commitment to a Chosen Course of Action," by Barry M. Staw (Organizational Behavior and Human Performance, 1976).
  • Alliance for Decision Education.

• EXTRAS:
  • "How to Make Your Own Luck," by Freakonomics Radio (2020).
  • "How Do You Know When It’s Time to Quit?" by No Stupid Questions (2020).
  • "The Upside of Quitting," by Freakonomics Radio (2011).

Psychologist David Yeager thinks the conventional wisdom for how to motivate young people is all wrong. His model for helping kids cope with stress is required reading at Steve’s new high school.

• SOURCES:
  • David Yeager, professor of psychology at the University of Texas at Austin.

• RESOURCES:
  • 10 to 25: The Science of Motivating Young People: A Groundbreaking Approach to Leading the Next Generation―And Making Your Own Life Easier, by David Yeager (2024).
  • "A synergistic mindsets intervention protects adolescents from stress," by David Yeager, Christopher Bryan, James Gross, Jared Murray, Danielle Krettek Cobb, Pedro Santos, Hannah Gravelding, Meghann Johnson, and Jeremy Jamieson (Nature, 2022).
  • "Harnessing adolescent values to motivate healthier eating," by Christopher Bryan, David Yeager, Cintia Hinojosa, Aimee Chabot, Holly Bergen, Mari Kawamura, and Fred Steubing (Proceedings of the Natural Academy of Sciences, 2016).
  • "Breaking the Cycle of Mistrust: Wise Interventions to Provide Critical Feedback Across the Racial Divide," by David Yeager, Julio Garcia, Patti Brzustoski, William Hessert, Valeria Purdie-Vaughns, Nancy Apfel, Allison Master, and Matthew Williams (Journal of Experimental Psychology, 2014).
  • "The Influence of the National truth Campaign on Smoking Initiation," by Matthew Farrelly, James Nonnemaker, Kevin Davis, Altijani Hussin (American Journal of Preventive Medicine, 2009).
  • "Tobacco is Whacko Commercial," (2002).
  • "Florida Tobacco Pilot Program: Thanking Customers," (2000).
  • "Think, Don't Smoke PSA Commercial," (1999).
  • "The Mentor’s Dilemma: Providing Critical Feedback Across the Racial Divide," by Geoffrey Cohen, Claude Steele, and Lee Ross (Personal and Social Psychology Bulletin, 1999).

• EXTRAS:
  • "The Suit, Savile Row, and Smartly Dressed Men," by The Rest is History (2024).

She’s a botanist, a member of the Citizen Potawatomi Nation, and the author of the bestselling Braiding Sweetgrass. In her new book she criticizes the market economy — but she and Steve find a surprising amount of common ground.

• SOURCES:
  • Robin Wall Kimmerer, botanist and founder and director of the Center for Native Peoples and the Environment.

• RESOURCES:
  • The Serviceberry: Abundance and Reciprocity in the Natural World, by Robin Wall Kimmerer (2024).
  • Braiding Sweetgrass: Indigenous Wisdom, Scientific Knowledge and the Teachings of Plants, by Robin Wall Kimmerer (2015).
  • Gathering Moss: A Natural and Cultural History of Mosses, by Robin Wall Kimmerer (2003).
  • "The Deadweight Loss of Christmas," by Joel Waldfogel (The American Economic Review, 1993).
  • "Reproductive Ecology of Tetraphis pellucida. I. Population Density and Reproductive Mode," by Robin Wall Kimmerer (The Bryologist, 1991).

• EXTRAS:
  • "The Deadliest Disease in Human History," by People I (Mostly) Admire (2025).
  • "How Smart Is a Forest?" by People I (Mostly) Admire (2023).
  • "Jane Goodall Changed the Way We See Animals. She’s Not Done." by People I (Mostly) Admire (2022).