The evolution of the strategy based on the opponent's cooperativeness, in the population where different kinds of strategies coexist

Abstract

There are various concepts which can explain the evolution of cooperation, and we think that the player's decision making based on his/her opponent's "cooperativeness" (how cooperative the opponent is) is one of these ideas.\n Iwata&Akiyama(2010) showed that cooperation can evolve in the population where each player makes a decision referring to his/her opponent's cooperativeness.\n However, in the real world, the player who considers the opponent's cooperativeness and who doesn't consider one coexist in one population, so it's not natural to assume that all of the players have the same strategy.\n\nTherefore, in this study, we investigated if the strategy considering the opponent's cooperativeness evolves or not in the situation where players have different strategies in one group.\n\nAs a result, we've clarified the two following facts: (i) Whether the strategy referring to the opponent's cooperativeness can evolve depends on the network structure of the population. (ii) One strategy doesn't dominate the population, and both the strategy based on the opponent's cooperativeness and the strategy not based on it coexist in the population in the end.