Abstract
Skyrms describes how evolutionary models are helping us understand unselfish or cooperative behaviour in humans and animals. Mechanisms which can stabilize cooperative behaviour are sensitive to population densities, however. This creates the need for agent-based evolutionary models which depict individual interactions, spatial locations, and stochastic effects. One such model suggests that hostile environments may provide conditions conducive to the emergence and stabilization of cooperative behaviour. In particular, simulations show that random extinctions can keep population densities low, provide ongoing colonization opportunities, and insulate cooperative communities from invasion. Agent-based and population models play complementary roles in furthering our understanding evolutionary processes