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| Delay Discounting of Different Commodities: Opportunity Costs, Fungibility, and Alcohol |
| Monday, May 25, 2015 |
| 3:00 PM–4:50 PM |
| 006D (CC) |
| Area: EAB; Domain: Basic Research |
| Chair: Brent Kaplan (The University of Kansas) |
| Discussant: David P. Jarmolowicz (The University of Kansas) |
| Abstract: Discounting the process by which an outcome loses its value based on a number of contextual factors such as the delay to or likelihood of receiving the outcome. Further, different outcomes are discounted to different extents, especially when humans are the population under study. Much is unknown, though, regarding the extent of delay discounting of commodities other than money and the boundary conditions (e.g., fungibility) that result in different rates of discounting. This symposium will attempt to address some of these questions. The first talk examines the degree of discounting when opportunity costs are either present or absent. That is, during imposed delays to reinforcement, participants could either obtain reinforcement by doing other things or were required to complete minimal tasks. The next two talks investigate discount rates of various commodities and their fungibility, or the degree to which an outcome can be exchanged for alternatives. In these talks, both money and monetary alternatives (e.g., gift cards) and money and non-monetary alternatives are discounted to different extents, shedding light on the utility of various reinforcers. The last talk examines discount rates of alcohol and its relation to alcohol demand among college aged students using an individualized discounting assessment. |
| Keyword(s): Alcohol, Delay Discounting, Fungibility, Opportunity Costs |
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| Opportunity Costs of Reward Delays and the Discounting of Hypothetical Money and Cigarettes |
| PATRICK S. JOHNSON (Johns Hopkins University School of Medicine), Evan Herrmann (Johns Hopkins University School of Medicine), Matthew W. Johnson (Johns Hopkins University School of Medicine) |
| Abstract: Humans are reported to discount delayed rewards at lower rates than nonhumans. However, nonhumans are studied in tasks that restrict reinforcement during delays, whereas humans are typically studied in tasks that do not restrict reinforcement during delays. In nonhuman tasks, the opportunity cost of restricted reinforcement during delays may increase delay discounting rates. The present within-subjects study used online crowdsourcing (Amazon Mechanical Turk) to assess the discounting of hypothetical delayed money (and cigarettes in smokers) under four hypothetical framing conditions differing in the availability of reinforcement during delays. At one extreme, participants were free to leave their computer without returning, and engage in any behavior during reward delays (modeling typical human tasks). At the opposite extreme, participants were required to stay at their computer and engage in little other behavior during reward delays (modeling typical nonhuman tasks). Discounting rates increased as an orderly function of opportunity cost. Results also indicated predominantly hyperbolic discounting, the “magnitude effect,” steeper discounting of cigarettes than money, and positive correlations between discounting rates of these commodities. This is the first study to test the effects of opportunity costs on discounting, and suggests that procedural differences may partially account for observed species differences in discounting. |
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| A Test of the Economic Concept of Fungibility: Temporal Discounting of Money and Gift Certificates |
| TODD L. MCKERCHAR (Jacksonville State University), James E. Mazur (Southern Connecticut State University), Timothy Marshall (Jacksonville State University), Freeman Cumming (Jacksonville State University), Cassidy McDougale (Jacksonville State University) |
| Abstract: The economic concept of fungibility predicts the utility of an outcome should be positively correlated with the amount of exchange opportunities it allows. From this view, money is highly fungible and thus should have greater value than monetarily equivalent rewards with fewer exchange options (e.g., $100 gift certificate). We conducted a test of the fungibility hypothesis with 51 college students by comparing their temporal discounting of small and large amounts ($200 and $25,000) of money, “supercenter” gift certificates (e.g., Target), and grocery store gift certificates (e.g., Publix). The discounting of all outcomes was very well described by a hyperboloid (R2 > .95). Area-under-the-curve analyses revealed that the larger outcomes were discounted significantly less than smaller outcomes. Furthermore, there was a significant effect of outcome type: money was discounted less than supercenter and grocery store certificates. These findings provide some support for fungibility as an explanation for the commonly observed differences in discount rates across outcomes. However, future work should compare the discounting of outcomes that vary more in their fungibility (as many of our participants indicated that they did their grocery shopping at a supercenter). |
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| Delay Discounting for Money and Personalized Non-Money Rewards |
| Allison Stuppy (Center for Addictions, Personality, and Emotion Re), Kayla Tormohlena (Center for Addictions, Personality, and Emotion Re), RICHARD YI (University of Maryland) |
| Abstract: Abundant evidence suggests primary rewards (e.g., food and drugs) are discounted more than monetary rewards. This finding is commonly attributed to money's high degree of fungibility. The purpose of the present study was to contrast, within-individual, delay discounting (DD) of monetary rewards and non-monetary non-fungible rewards. One hundred forty-six (146) undergraduate students completed all study assessments for course credit. Following a conventional DD for hypothetical money task in session 1, participants were asked about their intentions for spending all immediate and delayed money rewards. Participants returned one week later to complete a personalized DD for a non-fungible non-money task based on their stated intentions from session 1. A conventional hypothesis test revealed no significant difference between DD of money and non-money rewards. A more rigorous test of statistical equivalence indicated that while DD of money and non-money were not equivalent, this was due to lower rates of DD for non-money. Given that the DD for the non-money task assessed DD for less-fungible commodities (than money), the present results suggest that higher rates of DD for primary rewards observed in previous research are not due to the degree of fungibility. Potential interpretations will be discussed. |
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| On the Relation Between a Novel Measure of Beer Discounting, Demand for Alcohol, and Alcohol-Related Problems in College Students |
| SHEA M. LEMLEY (The University of Kansas), David P. Jarmolowicz (The University of Kansas), Brent Kaplan (The University of Kansas), Alexandria Darden (University of Kansas), Derek D. Reed (The University of Kansas) |
| Abstract: Consumption of alcohol by college students is common and has the potential to result in a variety of problematic consequences. However, traditional behavior economic approaches to study alcohol use present some difficulties, including the cumbersome administration and scoring of many discounting tasks and the time consuming aspects of these measures. The present study examined a novel beer discounting questionnaire, and its relation to money discounting, an alcohol purchase task, and the Young Adult Alcohol Consequences Questionnaire (YAACQ), a scale assessing self-reported occurrences of alcohol-related problems in college students. Participants from a lower level undergraduate course at a large Midwestern university completed these surveys during an in class session. A total of 105 participants were included in data analysis. Orderly relations were observed between beer and money discounting, demand for alcohol, and scores on the YAACQ and several of its subscales. |
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