Steven Pinker | When Everyone Knows That Everyone Knows

In Conversation with Annie Duke Common knowledge is necessary for coordination, for making arbitrary but complementary choices like driving on the right, using paper currency, and coalescing behind a political leader or movement. It’s also necessary for social coordination: everything from rendezvousing at a time and place to speaking the same language to forming enduring relationships of friendship, romance, or authority. Humans have a sixth sense for common knowledge, and we create it with signals like laughter, tears, blushing, eye contact, and blunt speech. But people also go to great lengths to avoid common knowledge—to ensure that even if everyone knows something, they can’t know that everyone else knows they know it. And so we get rituals like benign hypocrisy, veiled bribes and threats, sexual innuendo, and pretending not to see the elephant in the room. Pinker shows how the hidden logic of common knowledge can make sense of many of life’s enigmas: financial bubbles and crashes, revolutions that come out of nowhere, the posturing and pretense of diplomacy, the eruption of social media shaming mobs and academic cancel culture, the awkwardness of a first date. Artists and humorists have long mined the intrigues of common knowledge, and Pinker liberally uses their novels, jokes, cartoons, films, and sitcom dialogues to illuminate social life’s tragedies and comedies. Consistently riveting in explaining the paradoxes of human behavior, When Everyone Knows That Everyone Knows… invites us to understand the ways we try to get into each other’s heads and the harmonies, hypocrisies, and outrages that result. Steven Pinker is the Johnstone Professor of Psychology at Harvard University. He has won many prizes for his teaching, his research on language, cognition, and social relations, and his twelve books, including The Language Instinct, How the Mind Works, The Better Angels of Our Nature, Enlightenment Now, and Rationality. He is an elected member of the National Academy of Sciences, a two-time Pulitzer Prize finalist, and one of Time’s “100 Most Influential People in the World Today.” Annie Duke is an author, speaker, and consultant in the decision-making space, as well as Special Partner focused on Decision Science at First Round Capital Partners, a seed stage venture fund. Annie’s latest book, Quit: The Power of Knowing When to Walk Away, was released in 2022 from Portfolio, a Penguin Random House imprint. Her previous book, Thinking in Bets, is a national bestseller. As a former professional poker player, she has won more than $4 million in tournament poker. During her career, Annie won a World Series of Poker bracelet and is the only woman to have won the World Series of Poker Tournament of Champions and the NBC National Poker Heads-Up Championship. She retired from the game in 2012. Prior to becoming a professional poker player, Annie was awarded a National Science Foundation Fellowship to study Cognitive Psychology at the University of Pennsylvania, where she earned her master’s degree. In 2021 she returned to her alma mater as a Visiting Scholar, where she also teaches executive education. In 2023 Annie completed her PhD in Cognitive Psychology. Recorded September 25, 2025 Facebook: / authorevents Instagram: / flpauthorevents Twitter: / authorevents Podcast Archive: https://libwww.freelibrary.org/progra... The views expressed by the authors and moderators are strictly their own and do not represent the opinions of the Free Library of Philadelphia or its employees.