Evolution of cooperative turn-taking

Question: How can the evolution of turn-taking be explained in species without language? Features of model: Using a genetic algorithm incorporating mutation and crossover, we studied noisy decision making in three repeated two-player games in which we predicted on theoretical grounds that cooperative turn-taking would evolve and three games in which we expected synchronized cooperation to evolve. Ranges of key variables: We set population size to 20, number of rounds to be played by each pair in each generation to 200, and number of evolutionary generations to 2000, and we repeated each simulation 10 times to check the stability of the results. Results: Cooperative turn-taking and (unexpectedly) a form of double turn-taking evolved in the alternation games, and joint cooperation evolved in the synchronization games. We propose a mechanism to explain how cooperative turn-taking can evolve mechanically, even without communication or insight, as it did in our simulations.