American social scientist known for his contributions to a number of fields, including psychology, mathematics, statistics, and operations research, all of which he synthesized in a key theory that earned him the 1978 Nobel Prize for Economics.

Simon graduated from the University of Chicago in 1936 and earned his Ph.D. in political science there in 1943. After holding various posts in political science, he became a professor of administration and psychology at Carnegie-Mellon University in 1949, later becoming the Richard King Mellon University Professor of Computer Science and Psychology there.

He is best known for his work on the theory of corporate decision making known as “behaviourism.” In his influential book Administrative Behavior (1947), Simon sought to replace the highly simplified classical approach to economic modeling—based on a concept of the single decision-making, profit-maximizing entrepreneur—with an approach that recognized multiple factors that contribute to decision making. According to Simon, this theoretical framework provides a more realistic understanding of a world in which decision making can affect prices and outputs.

Crucial to this theory is the concept of “satisficing” behaviour—achieving acceptable economic objectives while minimizing complications and risks—as contrasted with the traditional emphasis on maximizing profits. Simon's theory thus offers a way to consider the psychological aspects of decision making that classical economists have tended to ignore.

Later in his career, Simon pursued means of creating artificial intelligence through computer technology. He wrote several books on computers, economics, and management, and in 1986 he won the National Medal of Science.