An Evolutionary Approach Towards Time Preferences∗

Genes are assumed to generate choice behavior in an environment where there are intertemporal tradeoffs. A gene survives the evolutionary process if it is not possible for a rare mutant gene to grow at a faster rate. Our goal is to represent the choice behavior of the surviving genes by a preference relation. We show that if choices affect the number of offspring but not the descendants’ reproductive ability, this representation is time consistent, the discount factor is the inverse of the population growth factor, and the felicity functions are the products of the reproduction functions and the survival probabilities. We also show that if newborn offspring are heterogeneous, for example due to transfers from parents, the preference representation is more subtle. The discount factor is still the inverse of the population growth factor, but the felicity function is essentially the sum of the expected discounted reproductive values of the individuals whom the parents’ choices affect.