A taste for variety
研究决策者在重复选择中，其收益取决于过去选择频率时，不同无限期收益评价方案下的最优策略，发现折现和极限下确界方案下平稳策略可达最优，而极限上确界方案则需满足特定条件。
A decision maker repeatedly chooses one of a finite set of actions. In each period, the decision maker's payoff depends on a fixed basic payoff of the chosen action and the frequency with which the action has been chosen in the past. We analyze optimal strategies associated with three types of evaluations of infinite payoffs: discounted present value, the limit inferior, and the limit superior of the partial averages. We show that when the first two are the evaluation schemes (and the discount factor is sufficiently high), a stationary strategy can achieve the best possible outcome. However, for the latter evaluation scheme, a stationary strategy can achieve the best outcome only if all actions that are chosen with strictly positive frequency by an optimal stationary strategy have the same basic payoff.