Delay of Gratification and Delay Discounting: A Unifying Feedback Model of Delay-Related Impulsive Behavior

Delay of Gratification (DG) and Delay Discounting (DD) represent two indices of impulsive behavior often treated as though they represent equivalent or the same underlying processes. However, there are key differences between DG and DD procedures, and between certain research findings with each procedure, that suggest they are not equivalent. In the current article, evidence is presented to support the argument that DG and DD measure discrete, yet related, processes involved in delay-related impulsive behavior. Also presented is a theoretical "feedback model" for the relation between DG and DD. In the model, it is proposed that the processes measured by DG are less cognitive and less learning-mediated than those measured by DD. However, as proposed, ability to sustain choices for delayed rewards (DG) is still represented in the choice processes measured by DD through an individual's learning history with DG types of situations; that is, the less a person is able to sustain choices for delayed rewards the more likely he or she will be to choose immediate rewards when given choices between larger delayed and smaller but more immediate options. The proposed model is consonant with observed consistencies and differences between DG and DD measures. From the proposed model, new research questions arise that would be lost in a continued conceptualization of DG and DD as equivalent measures.