against larger delayed rewards, both in the common currency of money. These tasks use permutations of rewards and delays that systematically vary the options and quantify the effects of delay on the value of the larger reward. By plotting the subjective value of the delayed reward across various delay periods, a discounting curve that reflects the magnitude of devaluation can be generated; two examples are provided in Figure 1. The more precipitously the reward loses value based on delay, the more impulsive the individual is considered. More importantly, the expressed preferences across the choices can be aggregated into a quantitative profile of how rapidly a delayed reward loses value to the individual, the discounting phenotype.
