Defined benefit pension plan inhibit the emergence of cooperation in the public goods games

As a social welfare, pension insurance has provided a great assistance to retiree in maintaining their livelihoods. In order to reward the contributions made by cooperators, an additional pension income is provided to them. In this paper, we study a public goods game based on the pension system on population structure, in which only cooperators can purchase pension insurance and receive pension benefits upon meeting specified conditions. In the simulation, we demonstrate the evolution of cooperation frequency over time and investigate the influence of insurance premium, pension baseline, the number of defected neighbors of cooperators, and the enhancement factor on the cooperation frequency. Additionally, we examine the impact of the pension system on cooperative behavior in triangular and hexagonal networks. Our results suggest that in the public goods game on networked structure, the pension system not only fails to promote cooperation but actually inhibits it, even when cooperators do not have to pay any costs and can receive pensions when conditions are met.