Thomas Schelling - Wikipedia
https://en.wikipedia.org/wiki/Thomas_Schelling
Thomas Crombie Schelling (April 14, 1921 – December 13, 2016) was an American economist .... 50016270, 163149563 · "War and Peace in the Nuclear Age; At the Brink" an interview with Thomas Schelling, 1986. Thomas C. Schelling at Goodreads ...諾貝爾經濟學獎昨天授予了托馬斯•謝林（Thomas Schelling）和羅伯特•奧曼（Robert Aumann），以表彰他們在促進對沖突與合作的理解方面所作的貢獻。
他們兩位都是"博弈論"（game theory）的先驅。作為經濟學的一個分支，博弈論目前在該學科研究中佔據主要地位，在政治理論、社會學甚至生物學等其他學科中也極為重要。兩位獲獎者將分享130萬美元的獎金。生於1921年的謝林先生是馬里蘭大學教授，他曾提出了衝突局勢理論，在上世紀50年代和60年代的冷戰時期，該理論極大地影響了美國政府對核威懾的態度。
他於60年代出版的著作《衝突的戰略》（The Strategy of Conflict），著力闡述了在雙方處於僵持時，採取一些戰略性手段的重要性。這些手段包括：事先承諾、邊緣政策和有威懾力的威脅。例如，通過限定你自己的選擇範圍，你就可以使對手清楚地知道，你將對他們的行動作出何種反應——不管他們採取什麼行動，這也就加大了他們作出讓步的可能性。謝林先生髮現，有威懾力的威脅也可以與邊緣政策配合使用，以逐漸提高發生衝突的機率。他補充說，兒童對邊緣政策的理解非常到位。
應用在核軍備競賽方面，上述理論為美國提供了處理一個根本問題的戰略，這個問題就是如何發揮那些殺傷力極大武器的作用，由於它們的殺傷力太大，人們並不認為會真的投入使用。
在地緣政治領域之外，謝林先生還發現，人通常都是願意合作的，但當他們在一個團隊中完全依理性行事時，則不那麼容易合作。奧曼先生對沖突與合作戰略思想的貢獻在於，他運用了邏輯學和數學來理解，當人們每天都面對相同對手或競爭者時，他們所能作出的選擇。
當戰略情形大量重複出現時，即便個體間有直接的利益衝突，達成合作的機率也會上升，因為每個個體在未來時間內，都會與另一方反复打交道。
奧曼率先提出的"重複博弈"分析，目前成為所有社會科學的主流分支，並已應用於政治衝突、灌溉系統、國際條約乃至公司相互勾結等各種各樣的問題。
博弈論同時也是1994年諾貝爾經濟學獎的獲獎學科，該獎授予約翰•哈薩尼(John Harsanyi)、約翰•納什(John Nash)及萊因哈德•澤爾騰(Reinhard Selten)。牛津大學納菲爾德學院 (Nuffield College) 教授保羅•克倫佩雷爾(Paul Klemperer)表示，(此次獲獎的)兩位經濟學家分別代表博弈論的不同觀點。謝林有著極佳的直覺，而奧曼是經濟學最為睿智和最善於抽象思維的學者。 "這是再自然不過的選擇，"他表示，"(博奕論的)整體方法論已在經濟學領域佔有極具支配力的地位。"
克里斯•賈爾斯(Chris Giles)是英國《金融時報》經濟學編輯
Nobel prize for 'game theory' thinkers
By Chris Giles, Economics Editor
The Nobel prize for economics was awarded yesterday to Thomas Schelling and Robert Aumann for their individual contributions to the understanding of conflict and co-operation.
Both were pioneers in "game theory", a branch of economics that now dominates the subject and is extremely important in other disciplines such as political theory, sociology and even biology. They will share the $1.3m (£740,000, €1m) prize. Born in 1921, Mr Schelling, a professor at the University of Maryland, developed a theory of conflict situations that strongly influenced US attitudes towards nuclear deterrence in the cold war period of the 1950s and 1960s.
His 1960 book, The Strategy of Conflict, highlighted the importance of precommitment, brinkmanship and credible threats as strategic weapons in a tense stand-off between two parties. By limiting your own options, for example, you can make it clear to opponents how you will respond to their actions, whatever they do, thereby increasing the chances the other side will back down. Credible threats could also be made with brinkmanship, gradually increasing the probability of a conflict, Mr Schelling observed, adding that children understood brinkmanship perfectly.
Applied to the nuclear arms race, the theories gave the US its strategies to deal with the fundamental problem of how to get some use from weapons so terrible that their use could not really be contemplated.
Outside the geo-political sphere, Mr Schelling also found that people tended to co-operate more readily than a group of them behaving purely rationally would. Mr Aumann's contribution to strategic thinking around the subject of conflict and co-operation came in using logic and mathematics to understand the options available to people when they face the same opponents or competitors day-in, day-out.
When strategic situations are repeated very large numbers of times, even when individuals have immediate conflicts of interest, the opportunity for building co-operation increases because the individuals have to deal with the other side again and again in the future.
The analysis of "repeated games", which Mr Aumann started, is now a mainstream part of all social sciences and applied to issues as diverse as political conflicts, irrigation systems, international treaties and collusion among companies.
Game theory was also the subject of the Nobel prize for economics sciences in 1994, when it was won by John Harsanyi, John Nash and Reinhard Selten. Paul Klemperer of Nuffield College, Oxford University, said the two economists came from different ends of the discipline, with Mr Schelling brilliantly intuitive and Mr Aumann one of the world's cleverest and most abstract economic thinkers. "It was an extremely natural choice," he said. "The whole methodology [of game theory] has been so dominant in economics."
七十五歲擁有以色列和美國雙重國籍的歐曼和八十四歲的美國經濟學者謝陵，因為在賽局理論的分析貢獻卓著，十日榮獲諾貝爾經濟學獎。
瑞典皇家科學院說，兩位學者「透過賽局理論分析，提升世人對衝突和合作的理解」，因而獲獎。
皇家科學院說，兩位學者的研究讓社會科學改變面貌，遠遠超越經濟領域，而且繼續重塑有關社會機構形成的辯論。
在冷戰時期，謝陵利用賽局理論方法解釋當代最重要的問題——全球安全和武器競賽。
歐曼則根據謝陵原有的構想，繼續利用數學分析工具，凸顯一個人的國家和敵國在衝突期間可資考量的抉擇。
謝陵是馬里蘭大學經濟學系教授，也是哈佛大學榮譽教授。歐曼是耶路撒冷希伯來大學理性中心教授。
皇家科學院說：「在許多真實世界情況中，長期關係或許比單一交手更容易維持合作，職是之故，分析短期賽局就往往失諸侷限。歐曼乃是針對所謂無限賽局進行完整正式分析的第一人。他的研究精確指出長期關係假以時日會有何種結果。」
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歐曼賽局 衝突→互動→勾結→合作
記者張幼芳／台北報導
電影「美麗境界」中，患精神分裂症的約翰納許經過痛苦掙扎，最後走出虛幻世界，在垂暮之年以少時論文「不合作賽局理論」摘下諾貝爾經濟獎桂冠；昨天，兩位高齡學者歐曼及謝陵，再次以賽局理論獲得諾貝爾經濟獎殊榮。
什麼是賽局理論？著有「賽局高手」的台大國際企業系教授巫和懋表示，賽局理論其實就是一種策略思考，透過策略推估，尋求自己的最大勝算或最大利益，從而在競爭中求生存。
巫和懋廿五年前在美國史丹福大學上過歐曼的課，他形容歐曼是個可愛而嚴格的老師，上課詼諧又很會東拉西扯，總是戴著猶太小帽，當時才五十幾歲的歐曼，頭髮已全白了。
他說，歐曼在美國長大，後來回到以色列帶動經濟學思潮，以色列有極強的經濟學派，都是因為他，而只要他指導過的博士生，都可以輕易取得美國頂尖大學的教職，影響力由此可見一斑。
昨天聽到歐曼獲獎，巫和懋直說「早就該得了」。
巫和懋說，納許在一九九四年獲獎的是「不合作賽局理論」；歐曼獲獎，則是對「合作賽局」的理論建構與分析。不合作賽局指只要對手的策略確定，競爭者就可以有最適反應，當一組策略是最適反應時，就是納許均衡。
歐曼的合作賽局是：在衝突的環境中，經過多次的互動（獎或懲），因為雙方產生隱性勾結，漸漸由對立到合作，最後達到雙贏的結果。
另外，歐曼對合作賽局的互動、均衡分配（如報酬），以及賽局理論的基礎分析，如每個人知道些什麼、對手的訊息掌握多少，都有完整的理論架構證明。他也是廣泛研究賽局理論的第一人。
另一得獎人謝陵則著眼於賽局的實務應用。巫和懋說，謝陵的賽局理論主要是在賽局中「經過適當的威脅，可以達到合理的結果」，合理的威脅指的是「不能不威脅，也不能威脅太過」。
古巴危機中，美國與蘇聯就曾運用這個理論（互相適當威脅），加上邊緣運用策略（雙方都在邊緣，不惜發動大戰），最後都決定撤飛彈，達到雙贏效果。美蘇冷戰時期，最後都未動用核武，也是此理論應用。
巫和懋說，兩人的賽局理論，從外交、政治到商場處處可見應用，影響層面深遠，諾貝爾獎從前給予「不合作賽局」理論殊榮，現在再給強調「如何由衝突到合作」的「合作賽局」肯定，應是它在學界的影響力不斷擴大，且在近來國際衝突不斷的情勢中，更彰顯出重要性。
編譯朱邦賢／美聯社斯德哥爾摩十日電
歐曼和謝陵十日榮獲諾貝爾經濟學獎，以下是瑞典皇家科學院的頌詞摘要。
為什麼有些個人、組織和國家能與人合作無間，其他人和組織、國家卻與人衝突不斷？歐曼和謝陵的研究已確定賽局理論或互動決定理論乃是主要關鍵。
謝陵證明，一造可以公然惡化自己的選擇而強化本身的立場，也證明報復的能力比抵抗攻擊的能力更有用，還證明不確定的報復比確定的報復更可靠，也更有效。凡此種種真知灼見，對化解衝突，避免戰爭都效力卓著。
重複賽局理論提升吾人對合作先決條件的理解：為什麼當有很多人參與，當他們不常互動，當互動可能中斷，當時間很短暫，或其他人的行動不能明確觀察時，就變得更困難？
對這些問題的真知灼見有助解釋諸如價格戰，貿易戰等經濟衝突，以及為何有些社會在管理共同資源方面比其他社會更成功。重複賽局理論澄清許多機構和機制的存在理由，這些機構和機制從商業協會和犯罪機構，到進行談判和國際貿易協定都是。
ublished: October 10, 2005
An American and an Israeli who worked independently of one another for decades were awarded the 2005 Nobel in economic science today for research on game theory that changed the way conflicts as diverse as trade wars and arms races are analyzed.
The $1.3 million Nobel Memorial Prize in Economic Science went to Thomas Schelling of the University of Maryland and Harvard and Robert Aumann of the Hebrew University of Jerusalem for writings published almost five decades ago that laid the analytical groundwork for the study of conflict and cooperation in the social sciences today, said the Royal Swedish Academy of Sciences, which administers the prize.
"Their work has transformed the social sciences far beyond the boundaries of economics," the prize committee said in announcing the winners today. "Current economic analysis of conflict and cooperation builds almost uniformly on the foundations laid by Aumann and Schelling."
"Game theory" is a mathematical method of analyzing the strategies that different "players" - be they governments, business partners or criminals - choose to achieve the best possible outcome for themselves in a given interaction.
Dr. Schelling, 84, a professor emeritus of economics at both the University of Maryland and Harvard, developed his vision of game theory in the early years of the cold war against the backdrop of the nuclear arms race between the United States and the Soviet Union.
In his influential book, "The Strategy of Conflict," first published in 1960, Dr. Schelling showed, for example, that a party could strengthen its bargaining position if it worsened its own options and that uncertain retaliation was more credible than actual retaliation. He used game theory to make the case that the credible threat of atomic weapons created by the 1945 bombing of Hiroshima was a key factor in ensuring that neither side in the cold war made use of their vast nuclear arsenals in the decades after.
"These insights have proven to be of great relevance for conflict resolution and efforts to avoid war," the academy said.
If Dr. Schelling's work has been widely recognized for establishing game theory as a major tool in the social sciences, Dr. Aumann's main contribution lies in pushing the mathematical framework of game theory forward, the academy said.
A mathematician at the Hebrew University of Jerusalem, Dr. Aumann, 75, was the first to develop a full mathematical analysis of so-called infinitely repeated games, in 1959, establishing what outcomes are sustainable over time in long-term social relationships between negotiating partners. His work demonstrated why cooperation is easier to secure the longer a relationship lasts and the fewer parties are involved in the negotiations. It has most notably been used to explain the behavior of companies competing in a capitalist marketplace, for example by demonstrating why, contrary to previous theories, price cartels can survive over time and how institutionalized cooperation is one response to conflict.
"Insights into these issues help explain economic conflicts such as price wars and trade wars," the prize committee's statement said. "The repeated-game approach clarifies the raison d'être of many institutions, ranging from merchant guilds and organized crime to wage negotiations and international trade agreements."
It is not the first time that a researcher on game theory has won a Nobel: John Nash, a Princeton mathematician who was the subject of a movie inspired by the 1998 book "A Beautiful Mind" by Sylvia Nasar, a former reporter for The New York Times, shared the economics award with two others in 1994.
Dr. Schelling began his career with work on the Marshall Plan, the American plan to rebuild a Europe devastated by World War II, spending two years Denmark and France and working in the White House before going to teach at Harvard in 1958. He is best known for his work on analyzing strategies in the context of global security, but also applied game theory to issues like environmental policy, racial segregation and organized crime.
Dr. Aumann was born in Frankfurt, Germany, before his family fled the Nazi regime in 1938 and settled in Israel. He holds American as well as Israeli citizenship. The two men, who will share the prize money, have never worked together.. "They linked us together because he is a producer of game theory and I am a user of game theory," Dr. Schelling told The Associated Press. "I use game theory to help myself understand conflict situations and opportunities."
It was the sixth year in a row that an American won or shared the economics prize.
Most recently, Edward C. Prescott, an Arizona State University professor, and the Norwegian Finn E. Kydland, an economics professor at the University of California, Santa Barbara, received the award last year for their work to show that innovative technologies and shocks, like a sharp increase in oil prices, play a much greater role in causing booms and busts than demand fluctuations.
The Nobel prize in economics is the only one of the Nobel awards that was not established in the will of the Swedish inventor and industrialist Alfred Nobel. Unlike the medicine, physics, chemistry, literature and peace prizes, which were first handed out in 1901, the economics award was established separately in 1968 by Sweden's central bank.
The academy's full announcement and biographies of the winners are available at http://nobelprize.org .
Robert Aumann
Mathematician Robert J. Aumann is a recipient of the 2005 Nobel Prize in Economics for explaining conflict and cooperation by means of game theory. Along with his American colleague, economist Thomas C. Schelling, Aumann's work "help[ed] explain economic conflicts such as price wars and trade wars, as well as why some communities are more successful than others in managing common-pool resources," according to the citation by the Royal Swedish Academy of Sciences .
Born in 1930 in Frankfurt, Aumann's family left Germany for the US in 1938. He earned his doctorate in mathematics in 1955 from the Massachusetts Institute of Technology and moved to Israel in 1956, where he taught mathematics at the Hebrew University of Jerusalem. Aumann is currently Professor Emeritus in the university's Center for Rationality, an interdisciplinary center which he helped to establish.
Thomas Crombie Schelling (born 14 April 1921 ) is an American economist and professor of foreign affairs, national security, nuclear strategy, and arms control at the University of Maryland, College Park School of Public Policy. He is the winner of the 2005 Nobel Prize in Economics for his work in game theory.
Schelling's most famous book, The Strategy of Conflict ( Harvard University Press, 1960), has pioneered the study of bargaining and strategic behavior and is considered one of the hundred books that have been most influential in the West since 1945.
In 1971 , he published a widely cited article dealing with racial dynamics called "Dynamic Models of Segregation". In this piece, he explained how a neighborhood of only white residents could quickly become a neighborhood of all black residents, even if none of the white residents were absolutely opposed to living in an integrated neighborhood.
Schelling has been involved in the global warming debate. Drawing on his experience with the post-war Marshall Plan, he has argued that addressing global warming is a bargaining problem: if the world is able to reduce emissions, poor countries will receive most of the benefits but rich countries will bear most of the costs.
Dr. Schelling previously taught for twenty years at Harvard University's John F. Kennedy School of Government, where he was the Lucius N. Littauer Professor of Political Economy.
He won, with Robert Aumann, the 2005 Nobel Memoriam Prize in Economics, for "having enhanced our understanding of conflict and cooperation through game-theory analysis".
External links
Nobel Prize Announcement (http://nobelprize.org/economics/laureates/2005/index.html )
More information about that Nobel Prize (http://nobelprize.org/economics/laureates/2005/info.pdf )
Laudatio (on Schelling) (http://web.eur.nl/diesnatalis/2003/schelling/laudatio/ ), by Maarten C.W. Janssen.
Foreign Affairs article by Schelling on Global Warming ( http://www.foreignaffairs.org/20020501facomment8138/thomas-c-schelling/what-makes-greenhouse-sense.html).
Disinfopedia article on Schelling (http://www.disinfopedia.org/wiki.phtml?title=Thomas_Schelling ).
Interview with Schelling in 2005 ( http://www.richmondfed.org/publications/economic_research/region_focus/spring_2005/interview.cfm )
2005.10.11 中國時報
諾貝爾經濟學獎揭曉 謝林、奧曼賽局理論發光
閻紀宇/綜合斯德哥爾摩十日外電報導
二○○五年諾貝爾經濟學獎今天揭曉，殊榮歸於兩位賽局理論（game theory，亦譯博弈理論）的前輩大師：美國籍的湯瑪斯．謝林，以及兼具美國與以色列公民身份的羅伯特．奧曼，以表彰他們擴充與應用賽局理論，大幅增進吾人對於衝突與合作的理解，其影響遠超出經濟學領域。
奧曼現年七十五歲，目前任教於以色列耶路撒冷希伯來大學「合理性研究中心」。謝林高齡八十四歲，是美國馬里蘭大學公共行政學院與經濟學系以及哈佛大學的榮譽教授。兩人將平分一千萬瑞典克朗（約新台幣四千三百萬元）獎金，並於十二月十日前往瑞典首都斯德哥爾摩領獎。
嚇阻理論 有助化解衝突
經濟學界的賽局理論濫觴於一九四○年代，五○年代開始大放異彩，電影「美麗境界」的主人翁納許正是箇中翹楚，他本人因此榮膺一九九四年的諾貝爾經濟學獎。時至今日，探討策略式互動行為的賽局理論，影響力遍及社會科學、全球經貿與國際政治領域。
謝林在一九五一年得到哈佛大學經濟學博士學位之後，開始將賽局理論運用到冷戰年代最重要的議題：全球安全與核武競賽，後來成為「嚇阻」理論的大師；他在一九六○年出版的《衝突的策略》，四十多年來始終是經典之作。謝林發現，對抗中的一方如果侷限自身的行動選項，甚至自斷後路，反而可以因此獲益；報復的能力比抵抗攻擊的能力更為重要；而且越不確定是否報復，要比確定報復，更具嚇阻力。
謝林的洞見不僅有助於化解衝突、避免戰爭，同時也促進了賽局理論的新發展，以及此一理論在社會科學各個領域的運用。尤其值得稱道的是，謝林對策略性承諾的分析，能夠解釋從企業競爭策略到政治決策權力的一系列現象，影響相當深遠。
重複賽局 促進和平合作
奧曼是麻省理工學院數學博士，後來揚名經濟學界，擅長以數學分析工具來拓展觀念與假說。奧曼與謝林一樣，對於參與者長時間多次互動的「重複賽局」尤感興趣，並進行了精闢的分析，能夠以簡潔扼要的公式推出準確的結果。
奧曼讓世人更加瞭解人類「合作」的先決條件，顯示就算賽局參與者之間在短期內有強烈的利益衝突，但是就長期的重複賽局而言，和平的合作往往才是均衡狀態。他的見解不僅有助於解釋價格戰、貿易戰等經濟衝突，也釐清了許多社會體制的存在理由。
Interview
Thomas Schelling
Thomas Schelling's early research was common fare for economists in the 1950s. The quality of the work may have been higher than most, but the topics were relatively mundane. His first two books were titled simply National Income Behavior and International Economics. But his interests extended beyond the traditional confines of the discipline, a point that was made clear with the publication of The Strategy of Conflict in 1960. In it, he used the tools of economics to illuminate important issues in international relations, while making significant contributions to game theory and laying the ground-work for later research in experimental economics.
Schelling has continued to publish on military strategy and arms control throughout his career, but his work has led him to a number of other seemingly disparate issues, such as racial segregation, organized crime, and environmental policy. In each case, he has been able to generate original insights from ordinary observation. As his long-time colleague Richard Zeckhauser has written, Schelling "thinks about the essence of phenomena. In scanning everyday behavior, he sees patterns and paradoxes that others overlook."
Schelling spent most of his career at Harvard University, before joining the faculty of the University of Maryland in 1990. He is a past president of the American Economic Association and recently worked with other distinguished economists on the Copenhagen Consensus, a project designed to prioritize the largest social problems facing the world. Aaron Steelman interviewed Schelling at his home in Bethesda, Md., on February 7, 2005.
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RF: Your early work focused on topics that were fairly conventional. How did your work progress into areas, such as strategic bargaining, that largely had been beyond the scope of economists?
Schelling: In 1948, I had just finished my coursework for the Ph.D. at Harvard, and a friend of mine called from Washington. He was working on the Marshall Plan and said that he had an opportunity to go to Paris but he couldn't leave until he had a replacement. So he asked me if I would like to replace him. I said sure.
Eventually, I went to Europe as part of this assignment and worked mainly on negotiations for the European Payments Union. Then, Averell Harriman, who had been head of the Paris office, went to the White House to be President Truman's foreign policy advisor. Harriman asked my boss to go with him, who in turn asked me a few months later to join him. In 1951, the foreign aid program was shifted to the Mutual Security Program, with Harriman as director, in the Executive Office of the President. I moved there, and stayed through the first nine months of the Eisenhower administration. So when I left, I had spent five years in the foreign aid bureaus, largely working on negotiations. That, I believe, was what focused my attention on the type of issues that showed up in The Strategy of Conflict.
RF: One of the more famous bargaining situations that you propose in The Strategy of Conflict involves a problem in which communication is incomplete or impossible – the game where two strangers are told to meet in New York City but have not communicated with each other about the meeting place. What does this game tell us about bargaining? And what, if any, are the policy implications?
Schelling: That little exercise, which I designed to determine if people could coordinate without any communication, became fairly famous and now I am usually identified as the originator of the idea of "focal points." My argument was that in overt negotiations something is required to get people to arrive at a common expectation of an outcome. And the ability to reach such a conclusion without communication suggested to me that there was a psychological phenomenon, even in explicit negotiations, which may work to focus bargainers eventually on that commonly expected outcome. By understanding that, I thought, we may be able to more easily facilitate policy negotiations over such matters as what would be an appropriate division of the spoils, an appropriate division of labor, and so forth. spoils与党の）官職, 役得.n
RF: What were the responses whe you originally posed this question to people?
Schelling: When I first asked that question, way back in the 1950s, I was teaching at Yale. A lot of the people to whom I sent the questionnaire were students, and a large share of them responded: under the clock at the information desk at Grand Central Station. That was because in the 1950s most of the male students in New England were at men's colleges and most of the female students were at women's colleges. So if you had a date, you needed a place to meet, and instead of meeting in, say, New Haven, you would meet in New York. And, of course, all trains went to Grand Central Station, so you would meet at the information desk. Now when I try it on students, they almost never give that response.
Some cities have more obvious focal points than others. For instance, if I asked people where would you meet in Paris, they probably would have no trouble. Most would go to the Eiffel Tower. But in other cities, it's not so clear.
The question first occurred to me while I was driving across country with two college friends. We were going from San Diego to New Hampshire and back, and camping along the way. We stopped in San Antonio and one of the other two guys got out and bought some peanut butter and crackers. While he was gone, a police officer made me move on, and because of the one-way streets, it took me about 10 minutes to get back to where I dropped him off, and he wasn't there. I kept circling around and eventually we found each other. But we realized that this could happen to us in any city, and we should come up with a plan about how to meet if we got separated.
We spent the whole afternoon thinking about it individually, but not talking about it, and that evening around the campfire we compared notes. We all wound up in the same place. The criteria we used were the following: Every city had to have this place and there could be only one of it, you had to be able to find it by asking any police officer or fireman, and you had to be able to reach it by public transportation. That narrowed the list down to the town hall or the main police station or the main post office.
Well, before we left home, we had each given our mothers a list of cities in which we would look for mail, and the way you get mail when you are traveling across country is to have the letter sent to your name, care of general delivery, and it arrives at the main post office in that city. That occurred to all three of us, and if we had to choose among the places that shared the criteria we described, the main post office seemed to be the obvious choice.
RF: You begin many of your papers with examples that are taken from everyday life. For instance, in "Hockey Helmets, Daylight Saving, and Other Binary Choices," you use the case of a player for the Boston Bruins who suffered a severe head injury to demonstrate why some collective action problems can be so difficult to solve – in this case, getting hockey players to voluntarily wear helmets. Is this a conscious strategy of yours to engage readers in what otherwise might seem like an abstract discussion?
Schelling: I always try to find something that I can put in the first paragraph to make the article sound interesting. It was just a coincidence that the hockey player had been hit in the head and that I had noticed it. It was a good example of a scenario in which everyone might wish to be compelled to do something that they wouldn't do on their own individually. So I think that has been part of my style. I wrote a textbook in international economics that had about a dozen policy chapters. I tried to have the first page of every chapter present an interesting puzzle or phenomenon that would get the interest of the readers.
RF: You have written that the "ordinary human being is sometimes ... not a single rational individual. Some of us for some decisions are more like a small collectivity than like the textbook consumer." Could you explain what you mean by this, perhaps through a few examples?
Schelling: I started working on that subject in the 1970s when I was asked to join a committee of the National Academy of Sciences on substance abuse and habitual behavior. I was the only economist there. Everyone else was a specialist on a certain type of addictive substance such as heroin or some other health problem like obesity. It seemed to be taken for granted that if you were addicted – whether to heroin or alcohol or nicotine – there wasn't much you could do for yourself. I argued that this was not the case, and gave a number of examples of ways people can help themselves avoid relapse.
For instance, one person tried to show how addictive heroin was by pointing out that many former users, even those who had avoided heroin for a long time, would be likely to use the drug again if they were to hang out with the people they used to shoot up with or even if they listened to the same music that they played when they used heroin in the past. I pointed out that there was some instructive material right there. Don't associate with the same people. Don't listen to the same music. And if the place where you used to use heroin is on your way to work, find a different route. So even though those people may be inclined to use heroin again, there were clearly some ways in which they could help prevent themselves from having a relapse.
The more I thought about this issue, the more I began to conclude that a lot of people have something like two selves – one that desperately wants to drink and one that desperately wants to stay sober because drinking is ruining his life and his family. It's as if those people have two different core value systems. Usually only one is prominent at a given time, and people may try to make sure that the right value system attains permanence by taking precautions that will avoid stimulating the other value system.
RF: Some have called you a "dissenter" from mainstream economics. But it seems to me that this is true only insofar as it concerns topics of inquiry. On methodological issues, you don't seem as willing to abandon some of the core assumptions of neoclassical economics as, say, those people who call themselves "behavioral economists." Do you think that this is a fair characterization?
Schelling: This is something that I talk about a lot. I claim that we couldn't do without rational choice. But we don't expect rational choice from a child or an Alzheimer's patient or someone suffering from shock. We will better understand the uses and limits of rational choice if we better understand those exceptions. I use the example of the magnetic compass. It's usually a wonderful way to determine which direction north is. But if you are anywhere near the actual north magnetic pole, the compass could point in any direction, even south. The same is true with rational choice. It is a wonderful tool if used when appropriate, but it may not work all the time. So I consider myself in the rational-choice school, absolutely. But I am more interested in the exceptions than many other economists tend to be.
As for the behavioralist critique of neoclassical economics, I would conjecture that if you walked into a classroom where a behavioralist is teaching microeconomics, that person would teach it in a straight, standard fashion. It's something that you have to master – you can't do without it. For instance, if a student were to ask about the effect of a gasoline tax on driving behavior, the response would likely be that such a tax will tend to lower consumption of gasoline and/or increase the desirability of more fuel efficient cars. That's just straight neoclassical economics.
More generally, I think that when a new idea develops, it is important that the enthusiasts are given free rein to explore and perhaps even exaggerate that idea. Once it catches on and becomes respectable, then it's time to become more critical. Rational choice has gone through that process, and the behavioralists have emerged to challenge some of its assumptions. The behavioralists have probably overstated their case, but their ideas are relatively new and will be critiqued as well.
I think that people like Dick Thaler and Bob Frank, who are clearly two of the most innovative behavioralist economists today, so much enjoy what they do that I'm not sure if they consciously exaggerate the role of these exceptional situations. When I read Bob Frank, I get the sense that he is passionate, almost emotional about his belief that American consumers are suffering welfare losses because they are spending their money trying to avoid the discomfort of not being equal to their neighbors. I think he overdoes it, and I think that I have told him so. I don't know if his answer today would be, "Of course I overdo it. I'm trying to get attention paid to something I think is important." Or if he would say instead, "No, I don't overdo it. I really do believe that the phenomenon is that important." But even if the former is true, I would excuse that. I think that the point is important enough that if exaggeration will help them get it across, let them exaggerate.
RF: What is your opinion of modern game theory?
Schelling: That's a hard one, because I don't keep up with all the latest work in that field. But I would like to make the following broad claims: Economists who know some game theory are much better equipped to handle a lot of important questions than those who don't. But economists who are game theorists tend to be more interested in the mathematics aspect of the discipline than the social sciences aspect. Some economists of the latter group are good at using their theoretical work to examine policy issues. Still, many – and I think this is especially true of young game theorists – tend to think that what will make them famous is their mathematical sophistication, and integrating game theory with behavioral observations somehow will detract from the rigor of their work.
I'll give you an example. I had a student at Harvard named Michael Spence, who a few years ago won the Nobel Prize. Mike wrote a fascinating dissertation about market incentives to engage in excessive competitive expenditure. I was on his committee, and I argued that he needed to do two things. First, summarize the theory in 40 pages. Second, find six to 10 realistic examples to illustrate how the theory worked and why it mattered. He spent much of a year doing that. But in the end, he published the 40-page version of his dissertation in a top-tier journal, and used that paper as the first chapter of a book. Both of them got a lot of attention, and led to his appointment to the Harvard faculty.
The reason that I advised him to take this approach was quite simple: If he didn't, other people would and they would get credit for his work because they were able to apply it to real-world questions. I think that other economists, especially young game theorists, can learn from this example. Even very technical work often can be used in an applied manner – and this can benefit the work as well as the economist.
RF: In 1950, few people would have predicted, I think, that the Cold War would end as peacefully as it did. For example, it is surely notable that the conflict ended without the use of nuclear weapons. Why do you think both sides avoided using means that would have had fairly certain, but catastrophic, consequences?
Schelling: I have written and lectured about this quite a bit. When I give a talk on the subject, I begin by stating, "The most important event of the second half of the 20th century is one that didn't happen." I think you have to go through the history to understand it fully. In the early 1950s, it was believed that the likelihood of the United States using nuclear weapons was so great that the Prime Minister of Great Britain came to Washington with the express purpose of persuading the Truman administration not to use them. And because the British had been partners in the development of nuclear weapons, their Parliament thought that the Prime Minister had a good right to share in any decision about how they would be used.
As we know, they were not used, but the Eisenhower administration repeatedly asserted that nuclear weapons were just like any other type of weapon, and that they could be used as such. The attitude in the Kennedy and Johnson administrations was quite different. They believed that nuclear weapons were fundamentally different, and their statements helped to build the consensus that their use was taboo – a consensus that may have dissuaded Nixon from using them in Vietnam.
Also, in the 1960s there was a great fear that dozens of countries would come to possess nuclear weapons. But the nonproliferation efforts were vastly more successful than most people expected. It was thought that Germany was bound to demand them, and that the Japanese couldn't afford to be without them. And then it would spiral down to other countries: the Spanish, the Italians, the Swedes, the South Africans, the Brazilians would all have nuclear weapons. The process by which these countries would acquire them, it was thought, was through nuclear electric power – the reactors would produce enough plutonium to yield weapons. For several reasons, that didn't occur.
Israel's restraint in the 1973 war was also very important, I think. Everyone knew that Golda Meir had nuclear weapons, and she had perfect military targets – two Egyptian armies north of the Suez Canal, with no civilians anywhere near. But she didn't use them. Why? Well, you could say, quite reasonably, that they didn't want to suffer worldwide opprobrium. I think, though, that there was probably another reason. She knew that if she did, the Iranians, the Syrians, and other enemies of Israel would likely acquire them and would not be reluctant to use them. In addition, it was not clear in the late 1970s that the Soviets shared the nuclear taboo. Yet, they didn't use them in their war against Afghanistan – and this was also very important.
There is a possibility that nuclear weapons will be used in the India-Pakistan dispute. But I'm not especially worried about that. The Indians and the Pakistanis have been involved in nuclear strategic discussions in the West for decades. They have had a long time to think about this, and have watched the U.S.-Soviet negotiations. I think they know that if they were to use nuclear weapons it could easily lead to something beyond their control. So I think that by now the taboo is so firmly entrenched, that it is very unlikely we will see nation-states use nuclear weapons. What we don't know is if that taboo holds for non-state actors. I think that it might, but I don't hold that opinion with much conviction.
RF: Some policymakers and analysts have argued that diplomacy is much more difficult in today's world than it was during the Cold War because there are now multiple non-state players who seem to place less value on stability than the Soviets did. How does this change the bargaining game? How can economics inform the current conflict with Islamic terrorists?
Schelling: One big difference is that you simply don't know who the non-state actors are. We have made a big deal out of Osama bin Laden. But we don't know if he is alive, and if he is alive, whether he still controls the money and organization in the way that he did a few years ago. Also, there are no recognized private channels of communication with non-state actors. If you want to get a message to bin Laden, you either hold a press conference and hope that he will hear it, or send it to him through a secret private channel.
Also, there is a popular notion that deterrence will not work when you are dealing with non-state actors. But I'm not so sure that this is the case. Consider the Taliban. I think that if the leaders of the Taliban had known what type of response the attacks of Sept. 11 would produce from the United States, they would have tried to prevent the attacks. So I think that we should consider what we can do to alienate bin Laden from some of his supporters. You also need to consider what types of weapons they are likely to use and what types of targets they are likely to choose. And we need to determine their objectives.
For instance, we still don't know what the objectives were of the attacks on the World Trade Center, because the effects were so widespread. It killed a lot of people. It produced the largest media coverage of a terrorist attack in history. It demonstrated U.S. vulnerability, while also destroying a symbol of Western capitalism. And it demonstrated the competence and some would say the bravery of the terrorists who were willing to sacrifice themselves. Each of those could have been the principal objective, or there could have been some combination of objectives. But we don't know for sure.
When we think about weapons, many people seem to think that terrorists will use whatever weapon they can get their hands on. But consider the use of, say, smallpox from a cost-benefit analysis. They could release smallpox in New York, Chicago, and San Francisco. But smallpox is a very difficult disease to contain in a world of global travel, and the United States is the country best equipped to deal with an outbreak. Releasing smallpox in the United States, then, could result in many more deaths in poor countries with relatively bad health systems like Indonesia and Pakistan than in the United States. I'm not sure that would be a result the terrorists would welcome. By unleashing such widespread death in the developing world – especially in places where they enjoy support today – they could substantially reduce their approval and assistance from people who are now their allies. In contrast, anthrax might be a more attractive option because it is not contagious, and its effects could be limited to the United States.
Also, there may be a cultural aspect to this. If releasing a noncontagious toxin in, say, a subway station is considered by large parts of Islamic culture to be a cowardly way to attack your enemy, then this could be costly to them. It could damage their support in the same way that releasing a contagious toxin could, even though the effects of the actual attack would be much more direct and localized.
RF: What do you think have been the greatest diplomatic successes and failures of the past 50 years?
Schelling: I think the great diplomatic success of the 20th century was the way the Marshall Plan morphed into NATO. Essentially, the cooperative arrangements between the Marshall Plan countries and the United States were absorbed when NATO was formed, and the good will was maintained. As a result, the United States was able to maintain excellent diplomatic relations with the other major Western powers for roughly 50 years. But recently that has started to unravel, and it's going to be very hard to get back the sort of camaraderie and mutual respect that we had built up.
As for other challenges, I think relations with Russia are much more complicated than they ever were with the Soviet Union. The power structure within the Kremlin may have been more complex than we understood at the time, but that didn't really affect the way we conducted diplomacy. I don't know what to say about the Israeli-Palestinian issue. I think that one of the greatest tragedies for diplomacy in the last few decades was the assassination of Prime Minister Rabin. The prospects for peace would have been much better, I think, had that not occurred.
There is one additional observation I would like to make. I think that technological changes have made diplomacy more centralized. Television, for instance, makes it possible for the U.S. Secretary of State to speak directly to billions of people around the world when she holds a press conference. Similarly, improved air travel makes it much easier for ambassadors to travel home to get instructions from the administration.
RF: I would like to talk about your famous checkerboard example as it applies to racial segregation. You have written, "A moderate urge to avoid small-minority status may cause a nearly integrated pattern to unravel, and highly segregated neighborhoods to form." Could you describe how this process unfolds?
Schelling: When I started thinking about this question, many American neighborhoods were either mostly white or mostly black. One possible explanation for this, of course, was rampant racism. But I was curious about how this might emerge in a world where racism was not particularly acute, where in fact people might prefer racial diversity.
The process works basically like this. Let's say the racial composition of a neighborhood is 55 percent white and 45 percent black, and that the majority population in the surrounding areas is utterly without prejudice. Then you may get a case where more and more members of the majority group move in. This may be fine with the minority group for a while. They may not mind going from being 45 percent of the population to 35 percent. But at some point – say, when their part of the population is only 20 percent – then the most sensitive members of that group will probably evacuate, reducing their percentage even further. The result is a highly segregated neighborhood, even though this wasn't the intent of the majority population.
I wanted to come up with an easily understandable mechanism to explain this phenomenon that I could use in teaching a class. I spent several summers at the RAND Corporation, which had a good library. I looked at several sociological journals, trying to find something I could use, but I wasn't able to find anything suitable. So I decided I would have to do something myself.
One day, I was flying home from somewhere and had nothing to read. So I passed the time by putting little "X"s and "O"s in a line, with one group representing whites and the other representing blacks, and used the assumption that there was a moderate desire to avoid becoming part of a very small minority group. Well, it turned out that this exercise was very hard to do on paper, because you had to keep erasing and starting over.
But my son had a coin collection at the time, and he had a bunch of copper coins and a bunch of zinc coins. I laid them out, and then I decided that putting them in a line wasn't good enough. You needed more dimensions. So I arranged them on a checkerboard. I got my 12-year-old son to sit down at the coffee table with me, and we would move things around. Soon, we got quite used to how it worked and how different the results were if one group was more discriminating than the other or if one group was more numerous than the other.
I published my results, and it got quite a bit of attention at the time. But it wasn't until 25 years later that I realized that this game had pioneered some of the work in what is called "agent-based modeling" and which is used in a variety of disciplines in the social sciences. At the time I was working out this example I didn't realize that I was engaged in an area of research that would one day have a formal name.
RF: You have done some research on crime. Why do you think some types of criminal activity become organized while others do not?
Schelling: Part of this is semantic. Let's say you have a group of automobile thieves. They may be organized, but we don't call that "organized crime." Instead, when we use that term we are almost always referring to a small group of activities: gambling, prostitution, and drugs are the big ones. My question was: What is it that characterizes those things we call "organized crime"? The answer is that they all exist as monopolies. There is strong demand for each of the activities I mentioned before, but each of them is illegal. So the people who work in those markets are relatively easy to extort because they cannot turn to the police. As a result, it is possible to gain something approaching monopoly power in those markets. So the bookmakers, prostitutes, and drug dealers are not really the perpetrators of organized crime. They are the victims.
When I looked at the issue more, though, I found that there were some markets that were legal but which were also characterized by high levels of extortion. Two were small laundry services and restaurants. What did they have in common? They were, at that time at least, mostly cash businesses and without well-documented accounting practices. So the proprietors of those businesses could pay the money under the table to the extortionist. And if they didn't, the extortionists would break their legs. Furthermore, if those businesses knew that their competitors in that market were being similarly extorted and thus realized that they were not being placed at a competitive disadvantage, they had less of an incentive to turn to the police.
RF: How did you become involved with the Copenhagen Consensus and what type of policy proposals has the group offered?
Schelling: I don't know precisely why I was chosen. Bjorn Lomborg, the organizer of the project, wanted to gather a group of economists of some reputation, and he probably knew that I had written about the greenhouse gas issue. So that was probably the connection.
When the project started we had a United Nations list of global problems related mostly to development and poverty. We were asked to look over that list and pick 10 that we thought would be worth pursuing. We did that, and then we asked a very distinguished person in that field to write a major paper on the issue, along with two other people to write critiques of the paper.
Somewhere along the way, we began to emphasize an idea that wasn't clear to me at the outset and that I think wasn't clear to many other people – namely, that this was mainly a budget priority exercise. We were supposed to do cost-benefit analysis. We were told that we had $50 billion to spend, and we should decide which projects would provide the most welfare benefit for the money.
Unfortunately, that approach had not governed our choice of projects and had not governed the way the papers were written. For instance, no one really had a good idea of what you could do with some part of $50 billion to generate more liberal trade. The same was true with education. The papers argued that unless you can reform the educational systems in the big industrialized countries, more money won't help. Similarly, it wasn't clear to us how more money would help us prevent the spread of financial crises. So we had about five topics that really did not fit, and we treated many of them as not applicable. In retrospect, I think we should have treated climate change in the same way.
Of those projects where we could see how the expenditure of money would help, restricting the spread of HIV and AIDS seemed like it should be at the top of the list. It is just so crucially important that we advocated spending about half of the money on it. Then there were some projects, like malnutrition and malaria control, where you just got so much for your money, that we put them near the top also. Projects to improve sanitation also were deemed quite worthwhile.
In general, I think that the program was successful in some ways and less successful in others. And if we had it to do all over again, I think that we could do an awful lot better.
RF: How did you come to the University of Maryland?
Schelling: In the 1980s, Congress passed a law making it illegal for most businesses to have a mandatory retirement age for most employees. But they allowed colleges and universities a seven-year grace period. Harvard, at the time, had mandatory retirement at 70, and I was going to be 70 before the grace period expired. Well, I was in good health, felt that there was more research that I wanted to do, and still enjoyed teaching. So I let it be known that I could be attracted to another university. My first preference was a university in Southern California, where I grew up. But then a former colleague and a very good friend of mine who was dean of the University of Maryland's School of Public Affairs called, and I told him about my situation. He asked me not to accept another offer until I heard from him. It also turned out that the chairman of the economics department had been my teaching fellow at Harvard in the 1960s. So I had two very close connections at Maryland, and I also knew a few other people on the faculty, like Mancur Olson. Plus, as we have discussed, much of my work is very policy-oriented, which made the Washington area pretty desirable to me. Overall, it seemed like this would be a good fit for me, so when the president of the university made me a very generous offer, I accepted it. I have been at Maryland since 1990. I still teach a class or two, but I am now in an emeritus position.
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