How Change Happens

How Change Happens

By Cass R. Sunstein

The different ways that social change happens, from unleashing to nudging to social cascades.





The different ways that social change happens, from unleashing to nudging to social cascades.

"Sunstein's book is illuminating because it puts norms at the center of how we think about change."—David Brooks, The New York Times

How does social change happen? When do social movements take off? Sexual harassment was once something that women had to endure; now a movement has risen up against it. White nationalist sentiments, on the other hand, were largely kept out of mainstream discourse; now there is no shortage of media outlets for them. In this book, with the help of behavioral economics, psychology, and other fields, Cass Sunstein casts a bright new light on how change happens.

Sunstein focuses on the crucial role of social norms—and on their frequent collapse. When norms lead people to silence themselves, even an unpopular status quo can persist. Then one day, someone challenges the norm—a child who exclaims that the emperor has no clothes; a woman who says “me too.” Sometimes suppressed outrage is unleashed, and long-standing practices fall.

Sometimes change is more gradual, as “nudges” help produce new and different decisions—apps that count calories; texted reminders of deadlines; automatic enrollment in green energy or pension plans. Sunstein explores what kinds of nudges are effective and shows why nudges sometimes give way to bans and mandates. Finally, he considers social divisions, social cascades, and “partyism,” when identification with a political party creates a strong bias against all members of an opposing party—which can both fuel and block social change.


$29.95 T ISBN: 9780262039574 344 pp. | 6 in x 9 in 0


$17.95 T ISBN: 9780262538985 344 pp. | 6 in x 9 in 0


  • Sunstein's book is illuminating because it puts norms at the center of how we think about change.

    David Brooks

    The New York Times

  • In this dense and technical, but illuminating, work influenced by behavioral science and political philosophy, legal scholar and policy theorist Sunstein (Nudge) further develops his ideas on how changes in attitude and behavior ought to happen.... This is a work that demands—but rewards—the reader's full attention. Starred Review.

    Publishers Weekly

  • Sunstein's book is illuminating because it puts norms at the center of how we think about change.

    The New York Times


  • It's often said that the only constancy in life is change. Cass Sunstein weaves threads from diverse traditions in behavioral science to explain how big shifts get started.

    Angela Duckworth

    Founder and CEO of Character Lab and Professor of Psychology, University of Pennsylvania; author of Grit: The Power of Passion and Perseverance

  • If you think you'd like to change something—another person, an organization, or even your  society—then try this test: Pick up this book and read five pages. If you don't have your eyes opened with a fresh insight or useful tool, well, you're probably not serious enough about making change.

    Chip Heath

    Professor, Stanford Graduate School of Business; coauthor of Switch: How to Change Things When Change is Hard

  • For those lamenting the status quo, and questioning whether change is possible, Cass Sunstein provides a ray of hope. Integrating insights from his own, and others', research on topics such as social norms, group polarization, and pluralistic ignorance with his intimate knowledge of law and public policy, Sunstein provides a road map of how change can and does happen. Characteristically wise and erudite, How Change Happens is a must-read for those who want to understand, and help to instigate, social change.

    George Loewenstein

    Herbert A. Simon University Professor of Economics and Psychology, Carnegie Mellon University

  • Many prominent scholars write about why desirable changes occur in some contexts but not others. None brings to the challenge the breadth of Cass Sunstein, or his depth of insight into the complexities involved. How Change Happens provides a breathtaking tour of the vast intellectual landscape on the subject, bringing into focus critical elements of the topography and interactions among its features. Academics and the wider public alike will benefit from Sunstein's profound ideas, lucid exposition, and engaging writing.

    Timur Kuran

    Professor of Economics and Political Science, Gorter Family Professor of Islamic Studies, Duke University

  • Cass Sunstein's new book is a tour de force exploring one of the most urgent problems of our time: how and why seemingly stable societal norms collapse and long-standing institutions come apart. Containing a feast of ideas on policy intervention, the book is bound to open up new avenues of research, and deserves to be read by students of economics, law, and politics.

    Kaushik Basu

    Professor of Economics and Carl Marks Professor of International Studies, Cornell University


  • Finalist in the Next Big Ideas Club for Spring 2019