In classical models on the evolution of cooperation, learning is modeled by imitation of successful strategies. However, it seems natural that individuals hesitate to unconditionally imitate their neighbor's acts, specially, when the costs for cooperation are high. When individuals are cautious and update their strategies combining their own strategies with the strategies of the successful individuals, the resistance to learning is the weight put on their strategies in the combination rule. When there is no resistance, the process corresponds to an exact imitation of the successful strategies. Otherwise, this process contributes to generating diversity into the population, in addition to prevent costly events.
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