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Abstract : |
We consider "competitive coevolution, " in which fitness is based on direct competition among individuals selected from two independently evolving populations of "hosts " and "parasites." Competitive coevolution can lead to an "arms race, " in which the two populations reciprocally drive one another to increasing levels of performance and complexity. We use the games of Nim and 3-D Tic-Tac-Toe as test problems to explore three new techniques in competitive coevolution. "Competitive fitness sharing " changes the way fitness is measured, "shared sampling " provides a method for selecting a strong, diverse set of parasites, and the "hall of fame " encourages arms races by saving good individuals from prior generations. We provide several different motivations for these methods, and mathematical insights into their use. Experimental comparisons are done, and a detailed analysis of these experiments is presented in terms of testing issues, diversity, extinction, arms race progress measurements, and drift. 1, |
