We present results from experiments in which a genetic algorithm (GA) was used to evolve
cellular automata (CAs) to perform a particular computational task-one-dimensional density
classification. We look in detail at the evolutionary mechanisms producing the GA's behavior
on this task and the impediments faced by the GA. In particular, we identify four “epochs of
innovation” in which new CA strategies for solving the problem are discovered by the GA,
describe how these strategies are implemented in CA rule tables, and identify the GA …