Reinhard Selten in 1994. (Stephan Jansen/AFP/Getty Images)

Reinhard Selten, a German economist and mathematician who won the 1994 Nobel Prize for his work on game theory, died Aug. 23 in Poznan, Poland. He was 85.

The University of Bonn, where he had taught since 1984, announced the death. No cause was reported.

Germany’s only Nobel laureate in the field of economic sciences, Dr. Selten shared the prize with John F. Nash Jr. of Princeton University and John C. Harsanyi of the University of California at Berkeley, both of whom developed concepts to explain human behavior through game theory.

Applied to fields as diverse as international relations, business-negotiation standoffs and biology, game theory attempts to predict human action based on the conflicting strategies of different parties. The academic study focuses largely on experimental methodology that requires participants to respond to various sets of circumstances in real-world situations, such as wars and political stalemates.

“Predicting human actions is also a goal of game theory, but it is more the question of, what would rational players do in a game?” Dr. Selten said in a 2004 interview with journalist Marika Griehsel.

Dr. Selten’s work involved refining Nash’s equilibrium concept by removing unlikely scenarios in which two or more players have nothing to gain by changing their strategies unilaterally.

He applied his theory of bounded rationality — whereby individuals make decisions based on limited information — to the war in Kosovo and to superpower rivalry in the Persian Gulf during the 1970s. He said the emergence of mass movements can weaken the theory’s accuracy, as shown by Ayatollah Ruhollah Khomeini’s unexpected rise to power in Iran’s 1979 revolution.

Reinhard Justus Reginald Selten was born on Oct. 5, 1930, in Breslau, a German city before World War II and now called Wroclaw in present-day Poland. His father ran a ­magazine-lending business, which the Nazi regime forced him to sell because he was Jewish.

Dr. Selten and his mother were Protestant, but his father’s Jewish roots forced Dr. Selten to leave school at 14, and he was refused entry to a trade. The family left Breslau and became refugees in the German states of Saxony and Hesse and in Austria, where he worked as a farm hand after the war.

While living in a village in Hesse, he had to walk 3½ hours to and from school. He used the time to solve mathematical problems, he said in his biography for the Nobel Foundation.

“My situation as a member of an officially despised minority forced me to pay close attention to political matters very early in my life,” he said in the Nobel biographical essay. “I had to learn to trust my own judgment rather than official propaganda or public opinion. This was a strong influence on my intellectual development.”

Dr. Selten received a master’s degree in mathematics from the Johann Wolfgang Goethe University in Frankfurt in 1957 and a doctorate four years later. After posts at the University of California and the Free University in Berlin, he was a professor of mathematical economics at the University of Bielefeld for 12 years.

Dr. Selten and his wife, the former Elisabeth Langreiner, were proficient in Esperanto, an invented language devised in the 19th century to assist international communication. Both were diagnosed with diabetes in 1991, and his wife later lost both legs below the knee because of the disease. They had no children.

Nash, the subject of the book and Oscar-winning film “A Beautiful Mind,” died last year in a car crash. Harsanyi died in 2000.

— Bloomberg News