Discounting of future rewards is traditionally interpreted as evidence for an intrinsic preference in favor of sooner rewards. However, temporal discounting can also arise from internal uncertainty in value representations of future events, if one assumes that noisy mental simulations of the future are rationally combined with prior beliefs. Here, we further develop this idea by considering how simulation noise may be adaptively modulated by task demands, based on principles of rational inattention. We show how the optimal allocation of mental effort can give rise to the magnitude effect in intertemporal choice. In a re-analysis of two prior data sets, and in another experiment, we reveal several behavioral signatures of this theoretical account, tying choice stochasticity to the magnitude effect. We conclude that some aspects of temporal discounting may result from a cognitively plausible adaptive response to the costs of information processing.

传统上，未来奖励的折扣被解释为一种内在的偏好，即希望获得更快的奖励。但是，如果人们假设对未来的嘈杂的心理模拟与先前的信念进行了合理的组合，则时间折现也可能由未来事件的价值表示的内部不确定性引起。在这里，我们基于理性的注意力不集中的原则，通过考虑如何通过任务需求自适应地调制仿真噪声来进一步发展该思想。我们展示了精神努力的最佳分配如何在跨期选择中引起规模效应。在对两个先前数据集的重新分析中，以及在另一个实验中，我们揭示了此理论帐户的几种行为特征，将选择随机性与量级效应联系在一起。