How does conformity promote the enhancement of cooperation in the network reciprocity in spatial prisoner's dilemma games?

Abstract

A new spatial prisoner's dilemma game model considering the conformity is proposed. A series of simulations confirms the present model bringing more enhanced network reciprocity than the conventional model. The observed enhancement is mechanically justified by relying the concept of END and EXP period. In line with more enhanced network reciprocity, we built a new spatial prisoner's dilemma (SPD) game considering conformity with presumption of lattice for underlying network and pairwise Fermi (PW-Fermi) for update rule. The key protocol is that a neighbor with more weight resulting from the conformity would be more likely selected as a pairwise opponent in the PW-Fermi updating process instead of random selection the conventional model presuming. A series of systematic simulations confirms that our model realizes more enhanced network reciprocity than the conventional SPD model. We elucidated its mechanism by means of considering on the concept of END period (meaning an initial period in which the global-cooperation fraction decreases from its initial value) and EXP periods (meaning the period following to END period in which global-cooperation increases) that substantially explaining how cooperative clusters survive in initial period and extend to defective zones afterwards.