The costs of delay: waiting versus postponing in intertemporal choice

Intertemporal choices are typically regarded as indicative of delay discounting. In this view, the degree of behavioral propensity to wait for a reward is attributed to an underlying process of reward devaluation as a function of delay. However, this widespread interpretation overlooks the role that the costs of delay might have in determining intertemporal choices. In this paper I review evidence of a marked discrepancy in intertemporal behavior across different tasks, and argue that the differential costs of delay can account for this anomaly better than alternative explanations. In particular, I characterize two types of delay, waiting versus postponing, examine how they impact behavioral choices across delay discounting tasks, what methodological challenges they present for new experimental paradigms, and what theoretical implications they have for our understanding of intertemporal choice.