We examine the evolutionary basis for risk aversion with respect to aggregate risk. We study populations in which agents face choices between alternatives with different levels of aggregate risk. We show that the choices that maximize the long-run growth rate are induced by a heterogeneous population in which the least and most risk-averse agents are indifferent between facing an aggregate risk and obtaining its linear and harmonic mean for sure, respectively. Moreover, approximately optimal behavior can be induced by a simple distribution according to which all agents have constant relative risk aversion, and the coefficient of relative risk aversion is uniformly distributed between zero and two.

翻译：我们探讨了针对总体风险的 风险厌恶的进化基础。我们研究了群体中个体在面对不同总体风险水平的选项时的选择行为。研究表明，最大化长期增长率的决策是由异质性群体诱导的：在该群体中，风险厌恶程度最低和最高的个体分别对承担总体风险与确定获得其线性均值与调和均值无差异。此外，近似最优行为可通过一种简单分布诱导：所有个体均具有恒定相对风险厌恶，且相对风险厌恶系数在零到二之间均匀分布。