A Biological Theory of Social Discounting
构建了一个增长模型，其中代际转移通过私人和公共资本存量实现。研究发现，私人储蓄选择通过个体选择演化，而公共储蓄决策通过群体选择形成，导致私人资本均衡回报率比公共资本高2-3%，表明社会跨期选择比个体选择更具耐心。
We consider a growth model in which intergenerational transfers are made via stocks of private and public capital. Private capital is the outcome of individuals' private savings while decisions regarding public capital are made collectively. We hypothesize that private saving choices evolve through individual selection while public saving decisions are the result of group selection. The main result of the paper is that the equilibrium rate of return to private capital is at least 2–3 percent more than the rate of return to public capital. In other words, social choices involving intertemporal trade-offs exhibit much more patience than individual choices do.