Discounting of delayed rewards is not hyperbolic.

Abstract

Delay discounting refers to decision-makers' tendency to value immediately available goods more than identical goods available only after some delay. In violation of standard economic theory, decision-makers frequently exhibit dynamic inconsistency; their preferences change simply due to the passage of time. The standard explanation for this behavior has appealed to the nature of decision-makers' discount functions, specifically positing a hyperbolic discount function. Though this explanation has been largely accepted, there has been surprisingly little work examining whether preference reversals are actually consistent with hyperbolic discounting. The current study holds hyperbolic discounting to the same empirical standard that exponential discounting has been held to and finds that choice behavior is not consistent with hyperbolic discounting. Despite the overwhelming focus placed on hyperbolic discounting, the current findings cast doubt on hyperbolic discounting as an explanation of decision-makers' undesirable preference reversals and as an explanation of delay discounting behavior in general.