A pioneering game theorist and Nobel laureate, Reinhard Selten fundamentally reshaped how we think about strategic interaction and decision-making. His influence lives on through his research and the many scholars he mentored.
On the occasion of his birthday on October 5, we are continuing our series of interviews with Reinhard Selten’s former students, colleagues, and close associates. They share personal memories and reflect on his enduring influence on economics. In the second interview of our series, we speak with Rosemarie Nagel, Professor at Pompeu Fabra University and the Barcelona School of Economics.
Which of Selten’s contributions do you think is most undervalued today?
What I think is particularly undervalued today is Selten’s idea of qualitative reasoning. In his work on actual human behavior, Reinhard often reasoned much more qualitatively than in his formal game-theoretical work. For example, Learning Direction Theory is based precisely on the idea that one may know approximately in which direction to change one’s next decision, without knowing by how much. He developed this more general idea in his work on boundedly rational qualitative reasoning and knew that he would probably not be able to bring this research program to completion himself, nor that it would make a major breakthrough in economics very soon.
The RSI takes particular pride in supporting researchers at the beginning of their careers. Is there any piece of advice or insight from Reinhard Selten that you would like to share with them?
Reinhard Selten very much liked supporting young researchers. He himself was always full of ideas that he had already thought about extensively but had no time to pursue, and he distributed these ideas generously. When I had no idea what to do for my Diplom thesis, he gave me a topic. I am still drawing on it today: my Diplom thesis was on learning in 2×2 games, and decades later I have returned to the same class of games with new theories and much larger data.
He also showed us that one should care about deep questions and not necessarily chase publications in top journals. At the same time, I learned from him that even the best professor is not always right when it comes to deciding whether one’s own ideas are worth pursuing. When we nevertheless insisted on taking a different path, he continued to support us in exactly the same way—although he might call us stubborn.
Is there a personal anecdote or memory of Reinhard Selten that you remember particularly fondly?
Selten’s classes and writing my Diplom thesis under his supervision brought me deeply into the “Geist der Wissenschaft”. Several decades later, I sent Reinhard some of my rather scientific-unscientific thoughts written down on PowerPoint slides, without really knowing what I expected him to tell me.
When we met shortly before Christmas in a café in Bonn, he handed my pages back to me in a transparent plastic folder and said with his calm voice: “This is poetry. Write a book. Make it unscientific. Do not destroy your career, and leave physics out of it—you do not understand enough about physics.”
For me, this permanently loosened the corset of the scientific mind, so that afterwards I felt I could move in and out of this scientific way of thinking. Reinhard himself never really did that. He looked at everything through the eyes of a scientist—even when he wrote a dictionary of cat language.
Click here to read the poem “The Rational Man as a Tuning Fork” by Rosemarie Nagel.
Click here to read the first interview of the series with Bernd Irlenbusch.