Study on Persistence of Cooperation without Reciprocity

摘要

We consider a population initially consisting of cooperators and defectors, who areengaged in a Prisoners' Dilemma. A cautious mutant is introduced who take some safeguard before cooperation. When meeting defectors, the mutant is assumed to avoid exploitation by using safeguard. According to replicator dynamics, there exists a fully mixed equilibrium consisting of naive cooperator, defector and cautious cooperator, a two-type equilibrium with cautious cooperators and defectors and the defectors- only corner solution. Depending on the parameters, these equilibria are evolutionary stable.