When Everyone Knows That Everyone Knows . . .: Common Knowledge and the Mysteries of Money, Power, and Everyday Life

 
　　為什麼每當有緊急狀況時，民眾紛紛搶購衛生紙？為何超級盃的足球賽事，會充斥著加密貨幣的廣告訊息？為什麼進行總統初選時，多數人會選擇「大家都會選」的候選人，而非自己最愛的那一位？
 
　　享譽全球的心理學大師史迪芬‧平克（Steven Pinker），同時也是《理性》（Rationality）、《再啟蒙的年代》（Enlightenment Now）等重量級著作的作者，剖析群眾心理、經濟選擇、人際互動等行為的背後，都與「共同知識」（common knowledge）有關。
 
　　舉例來說，為什麼在「國王的新衣」這個故事中，儘管國王、大臣還是百姓，都看到國王沒穿衣服，卻都以為這只是自己愚蠢的想法，而不敢承認？直到一個天真的孩子當眾指出「國王根本沒穿衣服！」的這一刻，當群眾發現除了自己認知到這件事之外，原來「大家也都知道（everyone knows）……」，才承認了這個事實、形成共識。在生活中，我們除了直接說出自己的想法，也經常透過目光、笑聲、眼淚、臉紅等非語言訊息，來創造共識和合作默契。
 
　　《When Everyone Knows That Everyone Knows . . .》融合生活各層面有趣的案例與學術研究結果，解析為何金融泡沫、股市崩盤、突如其來揭竿起義的革命、國與國之間的外交、約會中的男女心理關係、社群媒體文化……等諸多現象，都與「共同知識」的心理機制有關。書中同時揭示，在某些情況下，人們會刻意迴避顯而易見的問題，以謊言和偽善來避免形成共識。本書帶領我們洞悉人際、職場、經濟、社會中，隱而不顯的規則和矛盾，為各種看似非理性的行為提供了合理解釋。(文/博客來編譯)

**Selected by Bill Gates as One of Five Books to Read This Winter**

From one of the world’s most celebrated intellectuals, a brilliantly insightful work that explains how we think about each other’s thoughts about each other’s thoughts, ad infinitum. It sounds impossible, but Steven Pinker shows that we do it all the time. This awareness, which we experience as something that is public or ＂out there,＂ is called common knowledge, and it has a momentous impact on our social, political, and economic lives.

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. Along the way he answers questions like:

• Why do people hoard toilet paper at the first sign of an emergency?
• Why are Super Bowl ads filled with ads for crypto?
• Why, in American presidential primary voting, do citizens typically select the candidate they believe is preferred by others rather than their favorite?
• Why did Russian authorities arrest a protester who carried a blank sign?
• Why is it so hard for nervous lovers to say goodbye at the end of a phone call?
• Why does everyone agree that if we were completely honest all the time, life would be unbearable?

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, 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.＂