Human Networks Colloquium WHAT: David Lazer (Kennedy School of Government, Harvard University): "The Parable of the Hare and the Tortoise: The Network Structure of Exploration and Exploitation" WHEN: Friday, March 25, 2005, 1:00-2:00 PM EST WHERE: Bartos Theatre, MIT Media Lab (E15) HOSTED BY: Judith Donath, Assistant Professor of Media Arts and Sciences, MIT Media Lab Alex (Sandy) Pentland, Toshiba Professor of Media Arts and Sciences, MIT Media Lab SUMMARY: Networks provide the architecture of systemic adaptation. In any social system, the units of that system seek success—whether those criteria for success are determined by evolutionary processes or by (boundedly rational) goal-seeking processes. Networks provide the architecture of success in social systems because information about success that flows through the network provides one of the primary mechanisms for improvement in the system. This paper explores the implications of this architecture for system-level success, rather than nodal-level success. In particular, using simulation models, it demonstrates how network architecture affects the balance between exploration and exploitation (March 1991) within a system. It finds that small world (small number of degrees of separation) networks (the hare) are better at exploitation—they quickly converge on the best solution that exists in the network at the beginning of the simulation. However, small worlds perform very poorly at exploration, because they remain stuck on that solution. Larger world networks (the tortoise) perform better in the long run because they explore more of the solution space. This effect is greater the more local optima there are in the solution space. More generally, controlling for connectedness, we find that the smaller the world the better the system in the short run, and the worse it is in the long run. Finally, we observe how social cliques and network density affect the social outcome. BIO: David M. J. Lazer is associate professor of public policy at Harvard's Kennedy School of Government, where he teaches courses on regulation and public management. Lazer has an overarching interest in the process by which connections emerge among actors and the consequences that the resultant network has for individuals and the system. He is currently completing books on presidential control over the regulatory process and the use of DNA in the criminal justice system. With the support of the NSF, he is also in the process of launching a Web-based forum on the use of DNA in the criminal justice system (http://www.dnapolicy.net). He has also co-authored a series of papers on the diffusion of information among interest groups, and between interest groups and the government. He holds a PhD in political science from the University of Michigan. MIT Media Laboratory Home Page | Events Main Index