Thomas C. Schelling, Master Theorist of Nuclear Strategy, Dies at 95

Thomas C. Schelling, an economist and Nobel laureate whose interest in game theory led him to write important works on nuclear strategy and to use the concept of the tipping point to explain social problems, including white flight from urban neighborhoods, died on Tuesday at his home in Bethesda, Md. He was 95.

The death was confirmed by Richard Zeckhauser, a former student and colleague.

It was while working as an economist in the Truman administration that Professor Schelling became intrigued by the stratagems and negotiating ploys that he observed in international bargaining. In particular, as the Cold War developed, he became fascinated with the complexities of nuclear strategy, then in its infancy and a source of worldwide anxiety.

After spending a year studying nuclear weapons at the RAND Corporation in 1958 and writing “The Strategy of Conflict” (1960), he took his place as a leading theorist of nuclear war and peace along with the RAND intellectuals Herman Kahn and Albert Wohlstetter, as well as Henry A. Kissinger, the director of the Defense Studies Center at Harvard.

Professor Schelling analyzed superpower negotiations in the way that he analyzed the conflicts between, say, a blackmailer and his client, a parent and a child, or management and labor. In each case, he wrote, “there is a mutual dependence as well as opposition,” with each side seeking out tests of strength at less than crisis levels.

Among other counterintuitive propositions he put forth, Professor Schelling suggested that one side in a negotiation can strengthen its position by narrowing its options, using as an example a driver in a game of chicken who rips the steering wheel from the steering column and brandishes it so his opponent can see that he no longer controls the car. He also argued that uncertain retaliation is more credible and more efficient than certain retaliation.

“The Strategy of Conflict” introduced the concept of the focal point, often called the Schelling point, to describe a solution that people reach without benefit of communicating, relying instead on “each person’s expectation of what the other expects him to expect to be expected to do.”

People separated geographically, for instance, will rendezvous at a prominent landmark. Mr. Schelling used the example of strangers arranging to meet in Manhattan. Posing this problem to a group of students, he found that the most popular choice was the information booth at Grand Central Terminal at noon. The time and the place were given preference by tradition, and that preference was anticipated by all.

In “Meteors, Mischief and Wars,” published in Bulletin of the Atomic Scientists in 1960, Professor Schelling looked at the possibility of an accidental nuclear exchange between the United States and the Soviet Union and reviewed three novels that imagined such an event. The director Stanley Kubrick read his comments on the novel “Red Alert” and adapted the book for “Dr. Strangelove,” on which Professor Schelling was a consultant.

In the film, the Soviet “doomsday device,” set to respond automatically to a nuclear assault by the United States, was, Mr. Schelling said, a poor piece of gamesmanship.

“One obvious point in the Strangelove movie was that the Soviet doomsday thing was not a deterrent when the other side did not know in advance that it existed,” he pointed out in an interview with The New York Times in 2005, when he and the Israeli economist Robert J. Aumann were awarded the Nobel in economic science.

The prize, formally known as the Bank of Sweden Prize in Economic Sciences in Memory of Alfred Nobel, was conferred on both men for “having enhanced our understanding of conflict and cooperation through game-theory analysis.”

In the 1970s, Professor Schelling moved on to other social questions that seemed to be fertile ground for game theory, notably the dynamics behind racial change in American neighborhoods.

Expanding on the work of Morton Grodzins, a political scientist at the University of Chicago who used the term “tip point” to describe the crucial moment when white fears become white flight, Mr. Schelling offered a simple diagram, almost like a game board, to show how mixed urban neighborhoods could quickly become entirely black, even when white residents expressed only a slight preference for living among members of their own race.

His papers on the subject, and his book “Micromotives and Macrobehavior” (1978), achieved wider currency when his ideas were popularized by Malcolm Gladwell in his best-selling book “The Tipping Point” (2000).

Despite being identified with game theory, Professor Schelling described himself as an opportunistic user of its ideas, bringing them in when needed and sometimes not at all.

“When people ask me what game theory is, my answer is that it is an attempt to formalize any kind of study of strategic behavior where people are trying to affect or anticipate the behavior of others,” he told The Baltimore Sun. “So all kinds of people are game theorists. Organized labor of the 1930s. The underworld is full of extortionists who are good at it. Most of what I did with very few exceptions can be understood without having any idea what game theory is.”

Thomas Crombie Schelling was born on April 14, 1921, in Oakland, Calif. His father, John, was a Naval officer. His mother, the former Zelda Ayres, was a schoolteacher. His interest in mass unemployment in the Depression led him to major in economics at the University of California, Berkeley, where he earned a bachelor’s degree in 1944.

In 1947, he married Corinne Saposs. The marriage ended in divorce. He is survived by his wife, the former Alice Coleman; four sons, Andrew, Thomas, Daniel and Robert; two stepsons, Robert and David Coleman; a sister, Nancy Schelling Dorfman; eight grandchildren; four step-grandchildren; and three great-grandchildren.

Recibiendo el Premio Nobel (Schelling, a la derecha)

After working as an analyst for the federal Bureau of the Budget, Mr. Schelling enrolled in Harvard and, on completing his course work, spent two years in Denmark and France as an economist for the Economic Cooperation Administration, the agency created to carry out the Marshall Plan, the American effort to revitalize Europe after World War II.

In 1950, he joined the White House staff of the foreign policy adviser to the president, which in 1951, became the Office of the Director for Mutual Security, which managed all foreign aid programs.

He published his first book, “National Income Behavior: An Introduction to Algebraic Analysis,” in 1951, the year he received his doctorate from Harvard. He joined Yale’s economics department in 1953 and in 1958 became a professor of economics at Harvard, where he taught until 1990.

That year, he was named a distinguished university professor in the University of Maryland’s Department of Economics and School of Public Policy. He retired in 2003.

In “International Economics” (1958), his second book, Professor Schelling analyzed trade agreements and competition, but he had already begun to think about cooperation and conflict in a nuclear context. With the publication of “Games and Decisions: Introduction and Critical Survey” by Howard Raiffa and R. Duncan Luce in 1957, he began to apply game theory to his arguments.

In a long article that took up an entire issue of The Journal of Conflict Resolution in 1958, he tried to persuade game theorists to pay attention to a wide range of strategic activities, including promises and threats, tacit bargaining, the design of enforceable contracts and rules, and the tactics by which individuals or firms or governments committed themselves.

After becoming interested in theories of deterrence and limited war, he decided that nuclear strategy lent itself to his evolving ideas about bargaining and game theory. He explored this avenue at RAND, in the book “Strategy and Arms Control” (1961), written with the nuclear theorist Morton H. Halperin, and in influential papers like “Uncertainty, Brinkmanship and the Game of Chicken.”

One of his central arguments was that two sides to a conflict often reached tacit understandings rather than formal agreements.

In his Nobel speech, he noted that the Soviet Union took the public position that any European war would automatically become a nuclear conflict, yet at the same time, Moscow poured immense resources into building up conventional forces that in theory would be useless in a nuclear war.

This policy reflected an “unacknowledged arms-control understanding” between the United States and the Soviet Union that was, he said, the most important agreement of the Cold War, after the 1972 antiballistic missile treaty.

Professor Schelling explored nuclear bargaining further in “Arms and Influence” (1966).

“Dr. Strangelove” presented a different problem of conflict resolution. Peter George’s novel “Red Alert” was written in 1958, when bombers delivered nuclear weapons, but by the 1960s, intercontinental ballistic missiles had become the principal delivery system. Professor Schelling, conferring with Kubrick, George, Halperin and another nuclear theorist, William Kaufmann, tried to come up with a plausible screenplay using bombers.

“We had a hell of a time getting that damn war started,” he told The Sun. “We finally decided that it couldn’t happen unless there was somebody crazy in the Air Force. That’s when Kubrick and Peter George decided they would have to do it as what they called a nightmare comedy.”

Although Professor Schelling was identified in the public mind as a steely rationalist on the nuclear question — “These are the men who believe in the balance of terror, who feel that we must proceed with reason and think about the unthinkable,” a fellow academic critic complained about him and theorists like Herman Kahn in 1963 — he led a delegation of Harvard scholars in 1970 to sit down with Mr. Kissinger, then the national security adviser to President Richard M. Nixon, and voice opposition to the bombing of Cambodia.

It was around this time that Professor Schelling published “Models of Segregation” in The American Economic Review, to illustrate a law of unintended consequences. Using Xs and Os, he showed how one group — whether racial, ethnic, linguistic, economic or sexual — would inevitably set off an exodus merely by trying to avoid minority status in their neighborhood, even if its members stated a preference for living in a mixed neighborhood.

“Whites and blacks may not mind each other’s presence, may even prefer integration, but may nevertheless wish to avoid minority status,” he wrote in a different version of the essay “Micromotives and Macrobehavior.” “Except for a mixture of 50:50, no mixture will then be self-sustaining because there is none without a minority, and if the minority evacuates, complete segregation occurs.”

He then invited readers to test the model using pennies and dimes on a grid.

In other chapters of the book, Professor Schelling used thermostats, hockey helmets and the game of musical chairs to illustrate other problems of contingent behavior — behavior that depends on what other people do — and strategic interdependence.

In 2009, William Easterly, an economist at New York University, applied a real-world test to Mr. Schelling’s abstract tipping-point model of racial segregation. Analyzing census tract data for metropolitan areas of the United States from 1970 to 2000, he found more white flight out of neighborhoods with a high initial share of whites than out of more racially mixed neighborhoods.

“I continue to respect the Schelling model as a brilliant theoretical accomplishment that formalized loose language about ‘tipping,’” Mr. Easterly wrote in an email in 2011. “Indeed, it is only because of Schelling formalizing the tipping story and its predictions that it became feasible for me to test the conventional wisdom on tipping.”

Mr. Schelling later turned his attention to addictive behavior and climate change. In both, he found intriguing the strategies of self-constraint and bargaining, which he discussed in “Choice and Consequence” (1984) and “Strategies of Commitment” (2006).