Stochastic best response models provide sharp predictions about equilibrium selection when the noise level is arbitrarily small. The difficulty is that, when the noise is extremely small, it can take an extremely long time for a large population to reach the stochastically stable equilibrium. An...

The diffusion of an innovation can be represented by a process in which agents choose perturbed best responses to what their neighbors are currently doing.  Diffusion is said to be fast if the expected waiting time until the innovation spreads widely is bounded above independently of the size...

Stochastic learning models provide sharp predictions about equilibrium selection when the noise level of the learning process is taken to zero.  The difficulty is that, when the noise is extremely small, it can take an extremely long time for a large population to reach the stochastically...

Traditional game theory studies strategic interactions in which the agents make rational decisions. Evolutionary game theory differs in two key respects: the focus is on large populations of individuals who interact at random rather than on small numbers of players; and individuals are assumed...

Agent-based models typically involve large numbers of interacting individuals with widely differing characteristics, rules of behavior, and sources of information. The dynamics of such systems can be extremely complex due to their high dimensionality. This chapter discusses a general method for...

New ideas, products, and practices take time to diffuse, a fact that is often attributed to some form of heterogeneity among potential adopters. This paper examines three broad classes of diffusion models -- contagion, social influence, and social learning -- and shows how to incorporate...