The Evolution of Time Preference with Aggregate Uncertainty
研究跨期偏好的演化基础，发现当影响生存和繁殖的风险均为个体特有时，演化会选择最大化期望效用贴现和的个体，贴现率为人口增长率与死亡率之和；而总体生存不确定性会导致贴现率更高，并可能使个体偏离指数贴现。
We examine the evolutionary foundations of intertemporal preferences. When all the risk affecting survival and reproduction is idiosyncratic, evolution selects for agents who maximize the discounted sum of expected utility, discounting at the sum of the population growth rate and the mortality rate. Aggregate uncertainty concerning survival rates leads to discount rates that exceed the sum of population growth rate and death rate, and can push agents away from exponential discounting.