|Discounting Across Commodities and Contexts: Evidence for and Against a General Discounting Process|
|Tuesday, May 31, 2016|
|10:00 AM–11:50 AM |
|Zurich AB, Swissotel|
|Area: EAB/BPN; Domain: Basic Research|
|Chair: Amy Odum (Utah State University)|
|Discussant: Harriet de Wit (University of Chicago)|
Delay discounting, a measure of impulsive behavior, refers to the decline in value of an outcome as the delay to the receipt of that outcome increases. How quickly delayed outcomes lose value is a powerful predictor of problematic behaviors such as drug abuse, obesity, and risky sexual behaviors. A growing body of research demonstrates the way one outcome is discounted is highly related to the way other outcomes are discounted. This holds true even when outcomes are discounted at different rates. However, other research suggests that this finding is not universal and that how some outcomes are discounted is not related to other outcomes, suggesting that different processes may be involved in the discounting of different outcomes. Delay discounting is also related to important personal characteristics such as obesity, income and education. Establishing characteristics related to delay discounting could lead to better identification of individuals at risk for engaging in problematic behaviors. The presentations in this symposium investigate consistencies and inconsistencies of delay discounting across different outcomes as well as identify the important characteristics related to how an individual discounts delayed outcomes.
Delay and Probability Discounting Between Commodities as a Function of Nicotine Dependence
|SUZANNE H. MITCHELL (Oregon Health & Science University), Vanessa B. Wilson (Oregon Health & Science University)|
Current smokers, former smokers and never smokers were recruited to explore the role of smoking history and nicotine dependence in the valuation of commodities differentially related to cigarettes: alcohol, money. All participants performed the MCQ (Kirby et al 1999 JEP: General 128, 78-87) to assess delay discounting (choice between small rewards available immediately versus larger rewards available after a delay) as a function of commodity type and three delayed commodity amounts. An MCQ task was developed to assess probability discounting (choice between small rewards available with p(receipt)=1 versus larger rewards available with p(receipt)< 1). Both MCQs were compared to standard discounting tasks. Participating were sensitive to delay and probability, and were affected by commodity amount. Never and current smokers conformed to previously reported findings for delay and probability discounting for money but also for alcohol. However, differences between former smokers and never smokers varied as a function of discounting type and commodity. For delay discounting, former smokers discounted delayed money and alcohol more than never smokers. However for probability discounting, former smokers discounted money more but alcohol less. These data will be explored from the perspective of dependence history effects on commodity valuation, and differences between delay and probability discounting.
|A Latent Discounting Model: Confirmatory Factor Analyses of Delay Discounting|
|WILLIAM DEHART (Utah State University), Jonathan E. Friedel (Utah State University), Amy Odum (Utah State University)|
|Abstract: Delay discounting describes the process by which an outcome loses value as the temporal receipt to that outcome increases. A common finding in delay discounting research is the consistency of how different outcomes are discounted. For example, rapidly discounting money is predictive of rapidly discounting food. These findings provide evidence for a general discounting process indicating that although the degree of discounting may differ across commodities, the overall pattern of how an individual discounts delayed outcomes is consistent. However, to date evidence for this process has mostly been restricted to bivariate correlational analysis. Confirmatory factor analysis can be used to identify the factor structure of delay discounting. Our results suggest that although an overall delay discounting factor fits the data well, a separate non-monetary commodity factor is necessary to best fit the data in a student population, suggesting that non-monetary outcomes may involve additional processes. Importantly, some evidence exists that a single delay discounting factor is sufficient for describing cigarette smokers’ delay discounting behavior, indicating that cigarette smokers are more likely to discount all outcomes similarly. Results of this study suggest that delay has differential effects on different outcomes and that insensitivity to these differential effects may account for difference in delay discounting between groups.|
Steep Discounting of Delayed Gains, but Not Delayed Losses in Low, Income Alcohol-Dependent African Americans
|JOEL MYERSON (Washington University), Leonard Green (Washington University), Carissa van den Berk-Clark (Saint Louis University School of Medicine), Richard Grucza (Washinton University School of Medicine)|
Alcohol dependence is associated with steep discounting of delayed rewards, but its relation to the discounting of delayed losses and probabilistic rewards is unclear. Moreover, patterns of alcohol consumption vary considerably between communities, but previous research has not examined the relation between discounting and alcohol dependence in low-income African Americans. The present study evaluated whether low-income, alcohol-dependent African Americans differ from controls in their discounting of delayed rewards, delayed losses, or probabilistic rewards. African American participants, both alcohol-dependent cases and controls, were recruited from the same low-income neighborhoods, and propensity-score matching was used to further control for demographic differences. Three tasks assessed discounting of hypothetical monetary outcomes: delayed rewards, delayed losses, and probabilistic rewards. Alcohol-dependent cases discounted delayed gains, but not delayed losses or probabilistic gains, more steeply than their matched controls. The difference in discounting of delayed gains was localized to the male cases, whose discounting was steeper than either the male controls or the female cases; no gender difference was observed between male and female controls. The present results suggest that in low-income African Americans, alcohol dependence, particularly in males, may be more a reflection of choosing immediate rewards than of ignoring their delayed negative consequences.
Continuous Associations Between Delay Discounting and Addictive Behavior: A Meta-Analysis
|MICHAEL AMLUNG (McMaster University), Lana Vedelago (McMaster University), Tashia Petker (McMaster University), James MacKillop (McMaster University)|
Impulsive delay discounting (DD) is a core process in the reinforcement pathology of addictive disorders. This meta-analysis examines the magnitude of associations between DD and continuous addiction variables (e.g., quantity/frequency of use and addiction severity). A total of 63 studies met our inclusion criteria: alcohol (k = 19), tobacco (k = 15), cannabis (k = 1), stimulants (k = 3), opiates (k = 1), mixed (k = 14), and gambling (k = 10), yielding a total N = 9,428 across studies. Effect sizes (Pearsons r) for associations between DD and addiction variables were extracted. Preliminary results indicate that across studies there is a significant association between DD and both quantity/frequency (r = .14, Z = 5.89, p < .00001) and severity (r = .14, Z = 7.74, p < .00001), with varying effect sizes across addiction type. Additional analyses will compare effect sizes across different addiction types and will examine differences as a function of sample severity (e.g., clinical vs. subclinical). These results reveal consistent associations between DD and continuous measures of use and severity. More broadly, these findings converge with previous categorical studies to further support impulsive discounting as a core behavioral phenotype of addictive behaviors.