Discounting of delayed hypothetical money and food: Effects of amount (original) (raw)
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Within-Subject Comparison of Real and Hypothetical Money Rewards in Delay Discounting
Journal of the Experimental Analysis of Behavior, 2002
A within-subject design, using human participants, compared delay discounting functions for real and hypothetical money rewards. Both real and hypothetical rewards were studied across a range that included 10to10 to 10to250. For 5 of the 6 participants, no systematic difference in discount rate was observed in response to real and hypothetical choices, suggesting that hypothetical rewards may often serve as a valid proxy for real rewards in delay discounting research. By measuring discounting at an unprecedented range of real rewards, this study has also systematically replicated the robust finding in human delay discounting research that discount rates decrease with increasing magnitude of reward. A hyperbolic decay model described the data better than an exponential model.
Discounting of delayed hypothetical money, alcohol, and food
Behavioural Processes, 2003
For drug-dependent individuals, drugs of abuse that are delayed in time are discounted more steeply than money delayed in time in a hypothetical choice task. The reasons for this finding are not clear. This study examined whether steep discounting of drugs relative to money might be related to the function of drugs as primary/consumable reinforcers and money as a conditioned/non-consumable reinforcer. Twenty adults with no self-reported problems with money, alcohol, or food participated. They indicated their preferences for three hypothetical outcome types: delayed versus immediate money, delayed versus immediate food, and delayed versus immediate alcohol. Both the hyperbolic decay model and area under the curve analysis showed that money was discounted less steeply than alcohol or food, but that alcohol and food were discounted similarly. This finding replicates previous results showing that people without drug abuse problems show steep discounting of alcohol. Furthermore, this finding suggests that alcohol may be steeply discounted as part of a general process involving primary/consumable reinforcers, not necessarily because it is a drug.
Journal of Behavioral Decision Making
Research on delay discounting and inter-temporal choice has yielded significant insights into decision making. Although research has focused on delayed gains, the discounting of losses is potentially important in precisely those areas where the discounting of gains has proved informative (e.g., substance use and abuse). Participants in the current study completed both a questionnaire consisting of choices between immediate and delayed gains and an analogous questionnaire consisting of choices between immediate and delayed losses. For almost all participants, the likelihood of choosing the delayed gain decreased with increases in the wait until it would be received. In contrast, when losses (i.e., payments) were involved, different participants showed quite different patterns of choices. More specifically, although the majority of the participants became increasingly likely to choose to pay later as the delay was increased, some participants appeared to be debt averse, in that they were more likely to choose the immediate payment option when the delay was long than when it was brief. These debt-averse participants also were more likely to choose to wait for a larger delayed gain than other participants and scored lower on Impulsiveness than those who showed the typical pattern of discounting delayed losses. Taken together, these results suggest that in the case of delayed gains, people differ only quantitatively (i.e., in how steeply they discount), whereas in the case of delayed losses, people differ qualitatively as well as quantitatively, contrary to the common assumption that a single impulsivity trait underlies choices between immediate and delayed outcomes.
Delay discounting of different outcomes: Review and theory
Journal of the Experimental Analysis of Behavior, 2020
Steep delay discounting is characterized by a preference for small immediate outcomes relative to larger delayed outcomes and is predictive of drug abuse, risky sexual behaviors, and other maladaptive behaviors. Nancy M. Petry was a pioneer in delay discounting research who demonstrated that people discount delayed monetary gains less steeply than they discount substances with abuse liability. Subsequent research found steep discounting for not only drugs, but other nonmonetary outcomes such as food, sex, and health. In this systematic review, we evaluate the hypotheses proposed to explain differences in discounting as a function of the type of outcome and explore the trait-and state-like nature of delay discounting. We found overwhelming evidence for the state-like quality of delay discounting: Consistent with Petry and others' work, nonmonetary outcomes are discounted more steeply than monetary outcomes. We propose two hypotheses that together may account for this effect: Decreasing Future Preference and Decreasing Future Worth. We also found clear evidence that delay discounting has trait-like qualities: People who steeply discount monetary outcomes steeply discount nonmonetary outcomes as well. The implication is that changing delay discounting for one outcome could change discounting for other outcomes. Keywords delay discounting; temporal discounting; domain; commodity; trait Delay discounting, the decline in the present value of a reward with delay to its receipt, is a ubiquitous phenomenon (Odum, 2011a). Steep delay discounting is related to a wide variety of maladaptive behaviors that, although potentially rewarding in the short-term, are detrimental in the long-term (see Amlung et al., 2017; Bickel et al., 2019). Delay discounting is associated with drug abuse (see Mackillop et al., 2011) gambling (e.g., Alessi & Petry, 2003), obesity (see Barlow et al., 2016), risky sexual behaviors (e.g., Johnson, Johnson et al., 2015), preventative health behaviors, and personal safety (e.g., Daugherty & Brase, 2010). If delay discounting plays a causal role in these maladaptive behaviors, understanding the processes that lead to steep delay discounting is paramount.
Behavioural Processes, 2009
Procedural variants in estimating delay discounting (DD) have been shown to yield significant differences in estimated degree of DD as well as variations in individual patterns of choice. For example, a recent study found significantly different degrees of DD between groups assessed using either an ascending or descending order of presentation of the immediately available rewards. The purpose of this study was to test for within-subject effects of order of presentation of the immediate rewards in a DD task. In a single session, college students (N = 29) were asked to complete two DD tasks, one with the immediate rewards presented in ascending order and one in descending order. Consistent with previous results, significantly larger mean area under the discounting curve (AUC) was observed when the descending sequence was used compared to the ascending order of presentation; and the correlation between both measurements was moderate. These results suggest that some DD assessment tasks may be sensitive to contextual variables such as order and range of the reward and delay values.
Journal of Experimental Psychology: Learning, Memory, and Cognition, 2015
The value of an outcome is affected both by the delay until its receipt (delay discounting) and by the likelihood of its receipt (probability discounting). Despite being well-described by the same hyperboloid function, delay and probability discounting involve fundamentally different processes, as revealed, for example, by the differential effects of reward amount. Previous research has focused on the discounting of delayed and probabilistic rewards separately, with little research examining more complex situations in which rewards are both delayed and probabilistic. In two experiments, participants made choices between smaller rewards that were both immediate and certain and larger rewards that were both delayed and probabilistic. Analyses revealed significant interactions between delay and probability factors inconsistent with an additive model. In contrast, a hyperboloid discounting model in which delay and probability were combined multiplicatively provided an excellent fit to the data. These results suggest that the hyperboloid is a good descriptor of decision making in complicated monetary choice situations like those people encounter in everyday life.
Effects of Delay and Probability Combinations on Discounting in Humans
Behavioural Processes, 2016
To determine discount rates, researchers typically adjust the amount of an immediate or certain option relative to a delayed or uncertain option. Because this adjusting amount method can be relatively time consuming, researchers have developed more efficient procedures. One such procedure is a 5-trial adjusting delay procedure, which measures the delay at which an amount of money loses half of its value (e.g., 1000isvaluedat1000 is valued at 1000isvaluedat500 with a 10-year delay to its receipt). Experiment 1 (n = 212) used 5-trial adjusting delay or probability tasks to measure delay discounting of losses, probabilistic gains, and probabilistic losses. Experiment 2 (n = 98) assessed combined probabilistic and delayed alternatives. In both experiments, we compared results from 5-trial adjusting delay or probability tasks to traditional adjusting amount procedures. Results suggest both procedures produced similar rates of probability and delay discounting in six out of seven comparisons. A magnitude effect consistent with previous research was observed for probabilistic gains and losses, but not for delayed losses. Results also suggest that delay and probability interact to determine the value of money. Five-trial methods may allow researchers to assess discounting more efficiently as well as study more complex choice scenarios.
The Psychological Record, 2014
Delay and probability discounting occur when the subjective value of an outcome decreases because it is delayed or uncertain, respectively. Research using monetary outcomes has shown that both types of discounting are influenced by the magnitude of the outcome, but in the opposite direction. In Experiment 1, university participants completed a delaydiscounting task involving hypothetical monetary ($100 or 100,000)ormedicaltreatment(acneorbraincancer)outcomes.InExperiment2,universityparticipantscompletedaprobability−discountingtaskinvolvingthosesameoutcomes.ResultsfromExperiment1replicatedpreviousresearchinthatparticipantsdiscountedthe"smaller"outcomes(100,000) or medical treatment (acne or brain cancer) outcomes. In Experiment 2, university participants completed a probability-discounting task involving those same outcomes. Results from Experiment 1 replicated previous research in that participants discounted the "smaller" outcomes (100,000)ormedicaltreatment(acneorbraincancer)outcomes.InExperiment2,universityparticipantscompletedaprobability−discountingtaskinvolvingthosesameoutcomes.ResultsfromExperiment1replicatedpreviousresearchinthatparticipantsdiscountedthe"smaller"outcomes(100 & acne treatment) more than the "larger" ones ($100,000 & braincancer treatment). Results from Experiment 2 demonstrated that this magnitude effect reversed for probability discounting of the monetary outcomes, with 100,000discountedmorethan100,000 discounted more than 100,000discountedmorethan100. However, acne treatment was discounted more than brain-cancer treatment. This study represents the novel finding that the magnitude effect for medical outcomes may not reverse between delay and probability discounting as it does for monetary outcomes. The results suggest that delay and probability discounting are at least partially independent.
The combined effects of delay and probability in discounting
Behavioural processes, 2006
Human discounting studies have frequently observed hyperbolic discounting of rewards that are delayed or probabilistic. However, no studies have systematically combined delay and probability in a single discounting procedure. Indifference points of hypothetical money rewards that are both delayed and probabilistic were determined. Probabilities were converted into comparable delays according to the h/k constant of proportionality determined by Rachlin et al. (1991), and discounting rates were calculated. These data provided a very good fit to the hyperbolic model of discounting, suggesting that delay and probability can be combined into a single metric in studies of discounting. The inclusion of a magnitude condition found the Magnitude Effect commonly found in studies of temporal discounting. A temporal resolution of uncertainty condition found no effect. The present paper offers a novel statistical method, within an established framework, for the analysis of data from studies of discounting that combine delay and probability.
A comparison of four models of delay discounting in humans
The present study compared four prominent models of delay discounting: a one-parameter exponential decay, a one-parameter hyperbola . An adjusting procedure for studying delayed reinforcement. In: Commons, M.L., Mazur, J.E., Nevin, J.A., Rachlin, H. (Eds.), Quantitative Analyses of Behavior: The Effect of Delay and of Intervening Events on Reinforcement Value, vol. 5. Erlbaum, Hillsdale, NJ, pp. 55-73], a two-parameter hyperboloid in which the denominator is raised to a power [Green, L., Myerson, J., 2004. A discounting framework for choice with delayed and probabilistic rewards. Psychol. Bull. 130, 769-792], and a two-parameter hyperbola in which delay is raised to a power [Rachlin, H., 2006. Notes on discounting. J. Exp. Anal. Behav. 85, 425-435].