Coevolving predator and prey robots: Do "arms races" arise in artificial evolution?

Coevolution (i.e., the evolution of two or more competing populations with coupled fitness) has several features that may potentially enhance the powe r of adaptation of artificial evolution. In particular, as discussed by Daw kins and Krebs [3], competing populations may reciprocally drive one anothe r to increasing levels of complexity by producing an evolutionary "arms rac e." In this article we will investigate the role of coevolution in the cont ext of evolutionary robotics. In particular, we will try to understand in w hat conditions coevolution can lead to "arms races." Moreover, we will show that in some cases artificial coevolution has a higher adaptive power than simple evolution. Finally, by analyzing the dynamics of coevolved populati ons, we will show that in some circumstances well-adapted individuals would be better advised to adopt simple but easily modifiable strategies suited for the current competitor strategies rather than incorporate complex and g eneral strategies that may be effective against a wide range of opposing co unter-strategies.