The Influence of Conformity and Global Learning on Social Systems of Cooperation: Agent-Based Models of the Spatial Prisoner’s Dilemma Game

Individuals can learn about others from sources far from them, and conformity can operate not only on a local scale but also on a global scale. This study aimed to investigate the influence of conformity and global learning on social systems of cooperation using agent-based models of the spatial prisoner’s dilemma game. Three agent-based models incorporating differing types of global conformity were built and analyzed. The results suggested that global learning was generally unfavorable for cooperation. However, in some cases, it enabled resistance to the dominance of defection. Moreover, referring to more diverse sources was less harmful to cooperation than referring to a larger number of similar sources. Evolutionary dynamics were generated according to how competing forces of cooperative and defective agents were balanced. Random drifts toward either the cooperation- or defection-dominant state occurred under some parameter conditions. Whether the drifts were equally or unequally probable toward either state differed according to the parameter conditions. This study highlights the importance of individuals’ psychological biases in the evolution of cooperation. It also shows that differing practices of those biases can generate different dynamics, resulting in the system having different states.