Yale celebrates Larry Samuelson

 

Economist Larry Samuelson on Pioneering Game Theory Research at Cowles.  Yale professor Larry Samuelson's research was pivotal in the evolution of game theory economics. The former Cowles Foundation Director and president of the Econometrics Society sits down with Richard Panek to explain his motivations behind the work Samuelson is best known for. 

"Larry Samuelson was born in 1953 in Rockford, Illinois, then a solidly blue-collar, middle-class, Midwest industrial town. After high school Samuelson decided to go away to college—the University of Illinois at Champaign-Urbana (today, Urbana-Champaign), a three-hour drive from Rockford—although he had "not much of an idea” about what he wanted to study. Instead, he had chosen to attend college because, on the scale of good-for-me/bad-for-me, he guessed it would be more advantageous than the alternative.

"His willingness to take the road less traveled resurfaced when the time came to choose classes. He happened upon an economics course and, without knowing why, signed up. The course proved to be revelatory. The teacher was “particularly inspiring,” Samuelson says, but it was the subject itself that riveted him.

"He already knew that he liked mathematics—its “logic,” he says, its “beauty.” But in economics he discovered “an ideal blend of precision and rigor on the one hand, and relevance on the other hand.” After graduation he stayed at the University of Illinois to pursue a masters in economics and then a doctorate. “Being an economist,” he says, explaining the reasoning behind his choice of career, “you’re doing math in the service of what looked like some really important questions.”

"In the mid-1970s game theory wasn’t part of the standard curriculum in the study of economics; it was what Samuelson calls “a specialty.” Nonetheless, Illinois did offer a course on the topic, and as a graduate student Samuelson, once again electing for an option off the beaten path, took the course—and, once again, found a fortunate combination of inspiring instructor and compelling topic. One of the teachers in that class was Alvin E. Roth, future co-recipient, with Lloyd Shapley, of the Nobel Prize in Economic Sciences partly for his work on, yes, game theory.

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"After completing his PhD in economics at Illinois, Samuelson embarked on the life of an itinerant academic. For a year he taught at the University of Florida, Gainesville, then for three years at Syracuse University, then for the rest of the 1980s at Pennsylvania State University. In 1990 he settled down at the University of Wisconsin, Madison, and there he remained for nearly two decades, before joining the faculty at Yale in 2007. Along the way Samuelson became a leading figure in two subsets of game theory in economics.

One was evolutionary game theory.

At first, the evolution in evolutionary game theory was metaphorical. From the late 1980s through the 1990s, Samuelson studied scenarios in which players would adjust their behavior over the course of repeated plays of a single game, experimenting with various actions and gravitating toward those that had tended to bring good outcomes and away from actions that had produced disappointing results. The basic question was whether such learning would lead players in a game to a Nash equilibrium, and the basic answer, albeit with many caveats and qualifications, was yes: Stable outcomes of learning dynamics are Nash equilibria.

Then Samuelson began taking the word evolution more literally, extending his mathematical work on evolutionary game theory into biology. In collaboration with Yale evolutionary biologist and ornithologist Richard Prum, for instance, Samuelson studied cases of members of a species mimicking the members of other, typically more dominant, species. The example they used in a 2012 paper was the evolution of Downy Woodpeckers that are now nearly identical in appearance to the generally larger Hairy Woodpeckers.

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"More recently, Samuelson has extended his literal interpretation of the word evolution. Rather than using evolution to study other species, he has begun applying it to the biology of humans.  An old joke: The reason economists don’t sell their children is that they might be worth more later. And yes, Samuelson grants, “the mechanics of evolutionary selection are fundamentally selfish. Evolution selects for traits, behaviors, and preferences that increase the reproduction prospects of the individual, or indeed more precisely the gene.”

But.

“There's nothing intrinsic to economics that requires people to be selfish,” Samuelson says. Economic theory assumes that behaviors follow preferences, but it makes no assumptions about the content, whether selfish or selfless, of those preferences. “To an economist Mother Teresa is as good a model of economic behavior as is”—a pause—“Elon Musk might come to mind. Mother Teresa was as selfless as could be, but she followed that goal consistently and coherently, and one would have no trouble fitting that into an economic model.”

And because preferences “are the point of departure for models of individual behavior,” they are also the point of departure “for all of economics.” Biological and cultural evolution helped shape our preferences just as it helped shape many of our characteristics. By identifying aspects of preferences that would have conferred an advantage on our evolutionary ancestors, Samuelson’s research has allowed economists to sharpen their assumptions about preferences and therefore the subsequent economic analyses.  

In the late 1990s Samuelson began investigating the topic that would become his second major area of research: repeated games, especially the concept of reputations. As the name suggests, repeated games involve modeling that extends beyond the decision-making apparatuses of a one-off competition.

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"By the 2010s Samuelson had become somewhat of an elder statesmen in the field of game theory economics. In 2011 he was elected to the American Academy of Arts and Sciences. The following year he received a fellowship from the Society for the Advancement of Economic Theory. From 2014 to 2020 he served as the director of the Cowles Foundation, where he initiated a homecoming of sorts: In 1934 Alfred Cowles, champion of the use of statistics in economics, helped fund the launch of the Econometrics Society, and Samuelson, in his role at the head of the Cowles Foundation, orchestrated the transfer of the Society’s office to Yale. As of 2025 Samuelson is serving as the president of the Society.

Not surprisingly his five-decade immersion in game theory has affected his view of the world. “I think about incentives a lot,” he says. “If I had to summarize all of economics in one phrase, that phrase would be: Incentives matter. That sounds trite,” he quickly adds, “but it’s something people very easily lose sight of.”

So what, I wonder, was his incentive to sit for this interview? What went through his game theorist’s brain when the current director of the Cowles Foundation invited him to be the subject of the first of what might become a series of faculty profiles on the Cowles website? Can Samuelson describe his decision in terms of game theory?

He immediately defaults to a familiar framing.

“This could be good for the organization, and indirectly that’s good for me. Or,” he goes on, after a moment’s reflection, “at least it makes me feel good about me.”