Why do we follow unwritten rules, even when they seem outdated or downright harmful? In this episode, we explore how game theory explains the emergence and evolution of social norms. From duelling and foot binding to politicians' lapel pins and unwritten rules in negotiations, we discuss why norms can be so difficult to change, how they sometimes disappear, and why well-intentioned attempts to change them can backfire.

Peyton Young is the James Meade Professor of Economics Emeritus at the University of Oxford and a Senior Research Fellow at Nuffield College. A pioneer of evolutionary game theory and past president of the Game Theory Society, he has recently published his new book, The Dynamics of Social Norms (Oxford University Press, 2026).

Why do people stay honest when lying would pay off? In this episode, we discuss the economics of lying with our guest Chloe Tergiman. The discussion starts with the classic dice-rolling experiment and what it tells us about why people don't lie. Chloe then introduces the Announcement Game, a new experimental setup she, together with Marie Claire Villeval, developed. We discuss the relevance of 'plausible deniability' particularly when lying in repeated games in the experiment set up. Finally, we turn to a mechanism society has relied on for centuries: the oath. Chloe shows how asking participants to take an oath substantially changes behaviour. The takeaway: oaths matter, but they work best when they are public.

Chloe Tergiman is the Elliot Professor of Risk Management at the Smeal College of Business at the Pennsylvania State University.

In this episode, we speak with Dorsa Amir about randomness. Dorsa explains why acting randomly can be evolutionarily and strategically relevant for humans. She addresses the common perception that humans are "bad at being random" and, drawing on her research, sheds light on this question: our ability to be and act randomly may depend on the strategic nature and context of the situation in which randomness is required.
We then dive into anthropology, where Dorsa shares insights into how humankind has developed randomization devices across the world, offering many examples and anecdotes about their development.

Dorsa Amir is an Assistant Professor of Psychology and Neuroscience at Duke University. Her research explores how culture and cognition shape one another, drawing on developmental psychology, anthropology, and behavioural economics.