The Dominance Tournament Method of Monitoring Progress in Coevolution

In competitive coevolution, the goal is to establish an “arms race” that will lead to increasingly sophisticated strategies. The existing methods for monitoring progress in coevolution are designed to demonstrate that the arms race indeed occurred. However, two issues remain: (1) How can progress be monitored efficiently so that every generation champion does not need to be compared to every other generation champion? (2) How can a monitoring method determine whether strictly more sophisticated strategies are discovered as the evolution progresses? We introduce a new method for tracking progress, the dominance tournament, which provides an answer to both questions. The dominance tournament shows how different coevolution runs continue to innovate for different periods of time, reveals the precise generation in each run where stagnation occurs, and identifies the best individuals found during the runs. Such differences are difficult to detect using standard techniques but are clearly distinguished in a dominance tournament, which makes this method a highly useful tool in understanding progress in coevolution.