Downey, Haylee; Odum, Amy; Haynes, Jeremy; Galizio, Annie (Utah State University)
Faculty Advisor: Odum, Amy (Emma Eccles Jones College of Education & Human Services, Psychology Department)
Impulsivity has been associated with a wide range of poor health behaviors including substance abuse and unhealthy eating. Delay discounting, the tendency for more remote outcomes to be devalued, has been used as a measure of impulsivity. Delay discounting is often measured by asking individuals to choose several times between smaller sooner outcomes and larger later outcomes. In delay discounting, the domain effect refers to the tendency for different outcomes to be discounted at different levels (e.g., people tend to be more impulsive about food, alcohol, and entertainment than money). Thus, some researchers have suggested that the different rates of delay discounting for different outcomes reflect different processes (i.e., delay discounting for different outcomes is not necessarily correlated for individuals). Others suggest that delay discounting is a trait. If delay discounting is trait-like, we would expect that individuals who are more impulsive about money are also more impulsive about food, drugs, and other outcomes (i.e., individual degree of delay discounting is correlated for different outcomes). We examined 53 studies using systematic review techniques to examine delay discounting of different outcomes. For the 29 studies included in Analysis 1, we found evidence to support that delay discounting is a trait. Out of the 86 correlations we examined, 83 showed non-zero, positive correlation between delay discounting of money and delay discounting of an alternative outcome. For the 28 studies included in Analysis 2, we also found support for the domain effect, a state influence: discounting of money was lower than discounting of alternative outcomes in most comparisons. In conclusion, delay discounting appears to be a generalizable, unified process, involving both state and trait influences, thus demonstrating its potential as a behavioral intervention target.