He is a visiting research professor at IHS Vienna and a member of the external faculty at the Santa Fe Institute, where he has served as co-director of the economics program and on the institute's steering committee. He teaches and conducts research in general equilibrium theory and game theory, and also has research projects on natural resource management, network design, and evolutionary processes in markets and games. A Fellow of the Econometric Society, he received a BA in economics from Washington University in St. Louis and a PhD in economics from the University of California, Berkeley.