Why do we need to know that other people know we know? Neil deGrasse Tyson and comic co-host Chuck Nice dive into human psychology and how common knowledge is the invisible glue holding civilization together with cognitive scientist and author of When Everyone Knows What Everyone Knows, Steven Pinker. How do we know we know that other people know we know? We start with the biological roots of social coordination: does money only have value because we all agree it does? How do common knowledge generators, like eye contact and public ceremonies, differ from private information? Steven explains the two-way duplicity of weasel words and innuendo, revealing the logic behind benign hypocrisy. Why do we say "Netflix and chill" instead of being direct? Discover the game theory behind saving face, the necessity of plausible deniability in society, and how a psychologist bribes a waiter. We discuss the evolutionary purpose of blushing, laughter, and tears. We revisit Charles Darwin’s work on facial expressions as a tool against scientific racism, proving our shared ancestry through the universal language of emotion. We take a look at the Emperor’s New Clothes effect in modern politics and economics. From bank runs and the 1970s toilet paper shortage to the contest of crypto and primary elections, find out how common knowledge can trigger speculative bubbles and why breaking social norms can permanently shatter the common expectation of civility. Could spreading civil norms be the ultimate fix for a polarized society? Thanks to our Patrons Zypherior (Fjottrik), Brett Peterson, Sheila Weinhardt, baltimega, Eric Gouse, Mathias Toft, Mike, Alex Boyer, Joey, Nathan, Mark, logan, Tal Rozow, Craig F, Nathir Kassam, Doug Calli, Artem, Jay Sawyer, Owen Aston, Tyler, smbriggs1, Galaxy Master, Stephanie Edwards, Fahad Sadiq, Erasmus, Margaret Kaczorowski, Julia, Marie Rausku, Andrew Talley, Wayne2566, Rob Weber, Eric Cabrera, Galarian Rowlet, Mark S. Meadows, Alexander Burov, Christopher Knight, Dan, William Hughes-Ruddell, Lisa R., Alison Broussard, Alex M. Zepeda, Michael Kroll, Caroline Cockrell, Shakeel Kadri, Cassondra Lowe, Ethan Rudkin, Fabio Scopel, Denisse Bermudez, Jacqui Wakeley, Nick, Shelley, Christina, RT, Jan Souček, Christopher NAVARRETTE, Ken, Dek Shanaghy, Matthew Bosheh, Ms. Netta, Deciphering Yiddish, DxGhostHawk, Olga Cadilla, Rick Prunty, Young Hahn, Yen-Chen Lee, Gail Reed Lobo, Joe Horner, Eps15 Unc, HiTecLoLife, Shazia, PatienceHoney, James Watson, Alex Court, Rylan Accalia, Alex1016, Çağlayan (Chao) Karagözler, Nick Parks, Christopher Causey, William, Dana, Dagim Afework Mekonnen, joseph Rollins, ulus, Brent Knoll, Ron Mueller, Rosa Harris, Casey Hall, Jill Whalen, Honey Moon, Neicy, Justin Laning, Chris Mackenzie, Malik Sankofa, and Jeff Allmendinger for supporting us this week. Timestamps: 00:00 - Introduction: Steven Pinker 04:10 - Why Common Knowledge Matters 09:45 - Relationships, Weasel Worlds, & Plausible Deniability 17:30 - Why Cultures Differ From Eachother 20:37 - Why We Show Our Emotions 30:29 - When People Don’t Know That Everyone Knows 34:30 - Why Humor is Important 39:17 - Bank Runs, Toilet Paper, & Speculative Bubbles 44:37 - Violating the Social Contract 49:22 - Spreading Better Social Norms 51:47 - A Cosmic Perspective Check out our second channel, @StarTalkPlus Get the NEW StarTalk book, 'To Infinity and Beyond: A Journey of Cosmic Discovery' on Amazon: https://amzn.to/3PL0NFn Support us on Patreon: https://www.patreon.com/startalkradio FOLLOW or SUBSCRIBE to StarTalk: Twitter: http://twitter.com/startalkradio Facebook: https://www.facebook.com/StarTalk Instagram: https://www.instagram.com/startalk About StarTalk: Science meets pop culture on StarTalk! Astrophysicist & Hayden Planetarium director Neil deGrasse Tyson, his comic co-hosts, guest celebrities & scientists discuss astronomy, physics, and everything else about life in the universe. Keep Looking Up! #StarTalk #NeildeGrasseTyson