Naïve imitation and partial cooperation in a local public goods model

In a local interaction model agents play bilateral prisoners’ dilemmas with their immediate neighbors and have three possible strategies: altruistic, egoistic, partial cooperation. After each period the adopt strategy highest average payoff in observed neighborhood. There does not exist an absorbing state which partially cooperative coexists any of other strategies. The limits diffusion altruistic behavior population. Although clustering altruists is beneficial for sustaining altruism, relatively big groups at onset enable spread strategy.