Every decision that we make has both immediate and delayed consequences. As the delays to those consequences increase, the magnitudes of their subjective present values decrease--a phenomenon called delay discounting. Research on delay discounting has attracted growing interest in recent years because of the empirical success of the discounting model of impulsiveness, which describes impulsive choices as choices of smaller, more immediate rewards over larger, more delayed rewards. A person who has a high discount rate will weigh the future less than would a person with a low rate, and as a consequence will be more likely to make impulsive choices. Discount rates correlate with, for example, educational achievement, adolescent academic performance, drug and alcohol abuse, and pathological gambling.
In previous research, present values have been modeled quantitatively as a function of objective amounts and delays. As is well known, however, adding constant increments to an objective amount typically adds smaller and smaller increments to its subjective value--a phenomenon called diminishing marginal utility (DMU). Similarly, adding constant increments to objective time adds decreasing increments to our subjective experience of time. The primary objectives of this research are to examine the relationships between utility, time perception, and the quantitative form of discounting. The first series of experiments will examine the relationship between DMU and delay discounting. What role does DMU play in choices between discounted rewards? Conversely, might discounting of the delayed consumption of large rewards partly explain DMU? We will address these questions by modeling behavior in pairs of tasks. One task will assess the degree to which utility diminishes for each participant, and the other task will assess each participant's discounting of delayed rewards. A second series of experiments will examine the relationship between time perception and discounting. Does our subjective experience of time affect how we value future rewards? Might impulsivity arise in part because of subjective distortions in our anticipation of delay? In these experiments different pairs of tasks will be employed: one to model distributions of anticipated time delays and one to assess discounting at comparable time scales. Together, these experiments will improve our understanding of the processes underlying decisions that involve delayed outcomes. In addition to its practical importance, because all real world decisions have delayed consequences, understanding the effects of delay on choice is of fundamental importance to all areas of decision science.
