Evidence for Implicit Risk: Delay Facilitates the Processing of Uncertainty

Humans and other animals discount the value of rewards over time. One explanation for this is that delayed rewards may be less certain than immediate rewards, what has been referred to as the implicit risk hypothesis. Although this explanation is widely accepted, little research has directly assessed the validity of the implicit risk hypothesis. In the current study, we present two experiments in which participants made decisions about rewards involving both delay and uncertainty. By manipulating the order in which information was presented, we were able to investigate whether delay information facilitates beliefs about uncertainty and vice versa. It was found that participants were more likely to prefer larger, delayed rewards when information about delay was presented before information about uncertainty than when the information was presented in the opposite order. Additionally, we describe a process model that implements the implicit risk hypothesis and show that it is consistent with the observed patterns of data. These results support the implicit risk hypothesis and suggest that information about delay facilitates the processing of information about uncertainty.