Abstract

We introduce and study a simple generic model of neutral evolution of genotypes, designed to provide a feasible and general method for quantifying excess evolutionary activity|the extent to which evolutionary activity is the product of adaptive evolution. We compare the behavior of the generic neutral model against two other models: Packard's agent-based model of the evolution of sensory-motor functionality and a neutral \shadow" of Packard's model. Diversity and evolutionary activity of these three models across the mutation rate spectrum illustrate the feasibility and general applicability of the generic neutral model, con rm the appropriateness of using neutral models to quantify the extent of the continual adaptive success of genotypes, and reveal power-law dependences of evolutionary activity on mutation rate