Search

The Monetary Choice Questionnaire (MCQ) is a widely used behavioral task that measures the rate of delay discounting (i.e., k), the degree to which a delayed reward loses its present value as a function of the time to its receipt. Both 21- and 27-item MCQs have been extensively validated and proven valuable in research. Different methods have been developed to streamline MCQ scoring. However, existing scoring methods have yet to tackle the issue of missing responses or provide clear guidance on imputing such data. Due to this lack of knowledge, the present study developed and compared three imputation approaches that leverage the MCQ's structure and prioritize ease of implementation. Additionally, their performance was compared with mode imputation. A Monte Carlo simulation was conducted to evaluate the performance of these approaches in handling various missing responses in each observation across two datasets from prior studies that employed the 21- and 27-item MCQs. One of the three approaches consistently outperformed mode imputation across all performance measures. This approach involves imputing missing values using congruent non-missing responses to the items corresponding to the same k value or introducing random responses when congruent answers are unavailable. This investigation unveils a straightforward method for imputing missing data in the MCQ while ensuring unbiased estimates. Along with the investigation, an R tool was developed for researchers to implement this strategy while streamlining the MCQ scoring process., Competing Interests: Although the following activities/relationships do not create a conflict of interest pertaining to this manuscript and do not alter our adherence to PLOS ONE policies on sharing data and materials, in the interest of full disclosure, Dr. Bickel would like to report the following: W. K. Bickel is a principal of HealthSim, LLC; BEAM Diagnostics, Inc.; and Red 5 Group, LLC. In addition, he serves on the scientific advisory board for Ria Health; and serves as a consultant for Lumanity. Dr. Tegge would like to report the following: A. N. Tegge works on a project supported by Indivior, Inc. None of the other authors has any conflicts of interest to report., (Copyright: © 2023 Yeh et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Previous discounting research has focused on relatively simple situations (e.g., choosing between immediate and delayed gains, or between immediate and delayed losses) and the relations among amount, delay, and subjective value in such situations are now well established. Many everyday choice situations, however, are more complex, involving alternatives that combine gains and losses. In two experiments, participants discounted a monetary outcome that combined an immediate gain with a delayed loss. Consistent with the discounting framework, the value of the combination was approximately equal to the difference between the (undiscounted) value of the immediate gain and the (discounted) value of the delayed loss. More precise predictions of the relative subjective value of the delayed loss component of a combination were given by the same hyperboloid function that describes discounting in simple choice situations where outcomes only involve gains or losses, not both. As in previous studies, when the outcome was a simple one consisting of only a delayed loss, discounting was not affected by the amount of that loss. Surprisingly, however, when the loss was preceded by a gain, the degree to which the combination was discounted was affected by the amount of the loss. Notably, discounting of the delayed loss component of the combination decreased with the amount of the loss in a fashion similar to that observed with simple delayed gains, where smaller amounts are discounted more steeply than larger amounts. Choice situations involving immediate gains followed by delayed losses pose iconic self-control problems, and the present findings support the application of the discounting framework to these important everyday problems., (© 2022 Society for the Experimental Analysis of Behavior.)

Intertemporal choices require trade-offs between short-term and long-term outcomes. Ventromedial prefrontal cortex (vmPFC) damage causes steep discounting of future rewards (delay discounting [DD]) and impoverished episodic future thinking (EFT). The role of vmPFC in reward valuation, EFT, and their interaction during intertemporal choice is still unclear. Here, 12 patients with lesions to vmPFC and 41 healthy controls chose between smaller-immediate and larger-delayed hypothetical monetary rewards while we manipulated reward magnitude and the availability of EFT cues. In the EFT condition, participants imagined personal events to occur at the delays associated with the larger-delayed rewards. We found that DD was steeper in vmPFC patients compared to controls, and not modulated by reward magnitude. However, EFT cues downregulated DD in vmPFC patients as well as controls. These findings indicate that vmPFC integrity is critical for the valuation of (future) rewards, but not to instill EFT in intertemporal choice., Competing Interests: EC, FD, DK, JM, FB, VK, CC, LG, JM, SR No competing interests declared, (© 2021, Ciaramelli et al.)

Remembering and imagining specific, personal experiences can help shape our decisions. For example, cues to imagine future events can reduce delay discounting (i.e., increase the subjective value of future rewards). It is not known, however, whether such cues can also modulate other forms of reward discounting, such as probability discounting (i.e., the decrease in the subjective value of a possible reward as the odds against its occurrence increase). In addition, it is unclear whether there are age-related differences in the effects of cueing on either delay or probability discounting. Accordingly, young and older adult participants were administered delay and probability discounting tasks both with and without cues to imagine specific, personally meaningful events. As expected, cued episodic imagining decreased the discounting of delayed rewards. Notably, however, this effect was significantly less pronounced in older adults. In contrast to the effects of cueing on delay discounting, personally relevant event cues had little or no effect on the discounting of probabilistic rewards in either young or older adults; Bayesian analysis revealed compelling support for the null hypothesis that event cues do not modulate the subjective value of probabilistic rewards. In sum, imagining future events appears only to affect decisions involving delayed rewards. Although the cueing effect is smaller in older adults, nevertheless, it likely contributes to how adults of all ages evaluate delayed rewards and thus, it is, in fact, about time., Competing Interests: Declaration of competing interest None of the authors have any real or potential competing conflicts of interest to disclose that may influence the research and interpretation of the findings., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Discounting research has tended to focus on one simple situation, choice between an immediate, smaller gain and a larger, delayed gain, that is assumed by many to capture the essence of self-control. In everyday life, however, most choice situations are more complex, often involving combinations of gains and losses. We examined discounting in situations involving an immediate loss followed by a delayed gain that resulted in either a net gain (Experiment 1) or a net loss (Experiment 2) and compared it with discounting when there was only a delayed gain and no immediate loss. Larger delayed gains were discounted less steeply than smaller regardless of whether or not they were preceded by an immediate loss. Discounting functions of the same general hyperboloid form that describe the discounting of delayed gains in simple choice situations accurately described the discounting of combinations of gains and losses, although results differed depending on whether the combination would result in a net gain or a net loss. Participants consistently discounted loss-gain combinations less steeply than gains not preceded by an immediate loss when the combination represented a net loss (Experiment 2), but not when the combination represented a net gain (Experiment 1), a result analogous to the sign effect in simple choice situations (i.e., delayed gains are discounted more steeply than delayed losses). Taken together, these findings support the view that complicated choices like those common in everyday life can be understood within the discounting framework.

Rationale: Steep discounting of delayed monetary rewards by substance-dependent individuals is well-established. Less is known, however, about discounting other kinds of outcomes, and very little is known about discounting by marijuana-dependent individuals., Objectives: To determine how cocaine-dependent individuals and marijuana-dependent individuals discount various delayed and probabilistic outcomes, both positive and negative., Methods: Marijuana-dependent individuals, cocaine-dependent individuals, and controls performed delay and probability discounting tasks with various hypothetical outcomes., Results: The cocaine-dependent (but not the marijuana-dependent) group discounted delayed liquid rewards and monetary gains, but not delayed losses, more steeply than the control group. In contrast, the marijuana-dependent group (but not the cocaine-dependent group) discounted delayed monetary losses more steeply than controls. There were no group differences in discounting for any of the probabilistic outcomes. Factor analysis revealed a delayed gain factor, a probabilistic gain factor, and a delayed/probabilistic loss factor. The delayed gain factor scores for the cocaine-dependent group, but not the marijuana-dependent group, differed significantly from those of the control group. The groups did not differ in their probabilistic gain factor scores, and the marijuana-dependent group did not differ from the controls with respect to their loss factor scores., Conclusions: These results are inconsistent with the idea that steep discounting of both gains and losses and both delayed and probabilistic outcomes reflects a general impulsivity trait, as well as with the idea that all drug-dependent individuals are steep discounters. Rather, differences in discounting appear to be related to both the type of outcome and the specific drug on which individuals are dependent.

Rationale: Alcohol dependence is known to be 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., Objectives: The goal of the present study was to determine whether low-income, alcohol-dependent African Americans differ from controls in the degree to which they discount delayed rewards, delayed losses, or probabilistic rewards., Methods: African-American participants, both cases and controls, were recruited from the same low-income neighborhoods, and propensity-score matching was used to further control for demographic differences. Participants performed three tasks that assessed their discounting of hypothetical monetary outcomes: delayed rewards, delayed losses, and probabilistic rewards., Results: 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., Conclusions: The present results extend findings regarding discounting by substance abusers to a previously unstudied group, low-income African Americans, and suggest that in this group at least, alcohol dependence, particularly in males, may be more a reflection of choosing immediate rewards than of ignoring their delayed negative consequences.

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 2 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., (PsycINFO Database Record (c) 2015 APA, all rights reserved.)

111 Participants, recruited from Amazon's MTurk worker pool, completed Kirby's (2009) monetary choice questionnaire, which involves choosing between immediate, but smaller rewards and delayed, but larger rewards. Individual participants' responses were scored in three ways: first, by calculating the proportion of choices of the delayed rewards; second; using the scoring procedure described by Kirby et al. (1999) to estimate discounting rate (i.e., the value of the k-parameter in a hyperbolic discounting function); and third, using logistic regression to estimate discounting rate (Wileyto et al., 2004). Individuals' scores calculated using the proportion measure and the logarithms of their estimated k values were very strongly correlated (rs>.97). In addition, the proportions of choices of small, medium, and large amounts of the delayed rewards were strongly correlated (rs>.80). Taken together, these results suggest that the relative ease of calculating the proportion measure does not require sacrificing reliability. Moreover, the proportion measure is atheoretical and very easy to calculate whereas estimating an individual's discounting rate requires assuming a theoretical model that may not be appropriate. Significant differences in the proportion of delayed reward choices were observed between the small, medium, and large delayed reward amounts, with smaller rewards being discounted more steeply than larger ones, replicating previous findings of magnitude effects. These results provide further validation of the proportion of delayed reward choices on the Kirby questionnaire as a measure of individual and group differences in discounting., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The present study examined delay discounting of hypothetical monetary rewards over a wide range of amounts (from $20 to $10 million) in order to determine how reward amount affects the parameters of the hyperboloid discounting function and to compare fits of the hyperboloid model with fits of two discounting models used in neuroeconomics: the quasi-hyperbolic and the double-exponential. Of the three models assessed, the hyperboloid provided the best fit to the delay discounting data. The present delay discounting results may be compared to those of a previous study on probability discounting (Myerson, Green, & Morris, 2011) that used the same extended range of amounts. The hyperboloid function accurately described both types of discounting, but reward amount had opposite effects on the degree of discounting. Importantly, the amount of delayed reward affected the rate parameter of the hyperboloid discounting function but not its exponent, whereas the opposite was true for the amount of probabilistic reward. The finding that the exponent of the hyperboloid discounting function remains relatively constant across a wide range of delayed amounts provides strong support for a psychophysical scaling interpretation, and stands in stark contrast to the finding that the exponent of the hyperboloid function increases with the amount of probabilistic reward. Taken together, these findings argue that delay and probability discounting involve fundamentally different decision-making mechanisms., (© Society for the Experimental Analysis of Behavior.)

We examined the effect of holding reinforcement rate constant on delay discounting of hypothetical and real money when delays were actually experienced. In some conditions, participants were required to wait for the delayed rewards, and in some conditions, reinforcement rate was held constant by adding blackout periods after immediate rewards. Typical discounting occurred with the standard procedure and when there were no blackouts, but not when we held rate of reinforcement constant. Real and hypothetical money produced the same outcomes., (© Society for the Experimental Analysis of Behavior.)

The present study examined whether equivalent discounting of delayed rewards is observed with different experimental procedures. If the underlying decision-making process is the same, then similar patterns of results should be observed regardless of procedure, and similar estimates of the subjective value of future rewards (i.e., indifference points) should be obtained. Two experiments compared discounting on three types of procedure: adjusting-delay (AD), adjusting-immediate-amount (AIA), and adjusting-delayed-amount (ADA). For the two procedures for which discounting functions can be established (i.e., AD and AIA), a hyperboloid provided good fits to the data at both the group and individual levels, and individuals' discounting on one procedure tended to be correlated with their discounting on the other. Notably, the AIA procedure produced the more consistent estimates of the degree of discounting, and in particular, discounting on the AIA procedure was unaffected by the order in which choices were presented. Regardless of which of the three procedures was used, however, similar patterns of results were obtained: Participants systematically discounted the value of delayed rewards, and robust magnitude effects were observed. Although each procedure may have its own advantages and disadvantages, use of all three types of procedure in the present study provided converging evidence for common decision-making processes underlying the discounting of delayed rewards., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Individual discounting rates for different types of delayed reward are typically assumed to reflect a single, underlying trait of impulsivity. Recently, we showed that discounting rates are orders of magnitude steeper for directly consumable liquid rewards than for monetary rewards (Jimura et al., 2009), raising the question of whether discounting rates for different types of reward covary at the individual level. Accordingly, the present study examined the relation between discounting of hypothetical money and real liquid rewards in young adults (Experiment 1) and older adults (Experiment 2). At the group level, young adults discounted monetary rewards more steeply than the older adults, but there was no significant age difference with respect to liquid rewards. At the individual level, the rates at which young and older participants discounted each reward type were stable over a two- to fifteen-week interval (rs>70), but there was no significant correlation between the rates at which they discounted the two reward types. These results suggest that although similar decision-making processes may underlie the discounting of different types of rewards, the rates at which individuals discount money and directly consumable rewards may reflect separate, stable traits, rather than a single trait of impulsivity., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The present study with college students examined the effect of amount on the discounting of probabilistic monetary rewards. A hyperboloid function accurately described the discounting of hypothetical rewards ranging in amount from $20 to $10,000,000. The degree of discounting increased continuously with amount of probabilistic reward. This effect of amount was not due to changes in the rate parameter of the discounting function, but rather was due to increases in the exponent. These results stand in contrast to those observed with the discounting of delayed monetary rewards, in which the degree of discounting decreases with reward amount due to amount-dependent decreases in the rate parameter. Taken together, this pattern of results suggests that delay and probability discounting reflect different underlying mechanisms. That is, the fact that the exponent in the delay discounting function is independent of amount is consistent with a psychophysical scaling interpretation, whereas the finding that the exponent of the probability-discounting function is amount-dependent is inconsistent with such an interpretation. Instead, the present results are consistent with the idea that the probability-discounting function is itself the product of a value function and a weighting function. This idea was first suggested by Kahneman and Tversky (1979), although their prospect theory does not predict amount effects like those observed. The effect of amount on probability discounting was parsimoniously incorporated into our hyperboloid discounting function by assuming that the exponent was proportional to the amount raised to a power. The amount-dependent exponent of the probability-discounting function may be viewed as reflecting the effect of amount on the weighting of the probability with which the reward will be received.

Previously, we (McKerchar et al., 2009) showed that two-parameter hyperboloid models (Green and Myerson, 2004; Rachlin, 2006) provide significantly better fits to delay discounting data than simple, one-parameter hyperbolic and exponential models. Here, we extend this effort by comparing fits of the two-parameter hyperboloid models to data from a larger sample of participants (N=171) who discounted probabilistic as well as delayed rewards. In particular, we examined the effects of amount on the exponents in the two hyperboloid models of delay and probability discounting in order to evaluate key theoretical predictions of the standard psychophysical scaling interpretation of these exponents. Both the Rachlin model and the Green and Myerson model provided very good fits to delay and probability discounting of both small and large amounts at both the group and individual levels (all R(2)s>.97 at the group level; all median R(2)s>.92 at the individual level). For delay discounting, the exponent in both models did not vary as a function of delayed amount, consistent with the psychophysical scaling interpretation. For probability discounting, however, the exponent in both models increased as the probabilistic amount increased-a finding inconsistent with the scaling interpretation., (Copyright (c) 2009 Elsevier B.V. All rights reserved.)

In previous studies, researchers have found that humans discount delayed rewards orders of magnitude less steeply than do other animals. Humans also discount smaller delayed reward amounts more steeply than larger amounts, whereas animals apparently do not. These differences between humans and animals might reflect differences in the types of rewards studied and/or the fact that animals actually had to wait for their rewards. In the present article, we report the results of three experiments in which people made choices involving liquid rewards delivered and consumed after actual delays, thereby bridging the gap between animal and human studies. Under these circumstances, humans, like animals, discounted the value of rewards delayed by seconds; however, unlike animals, they still showed an effect of reward amount. Human discounting was well described by the same hyperboloid function that has previously been shown to describe animal discounting of delayed food and water rewards, as well as human discounting of real and hypothetical monetary rewards.

Decision making involves the allocation of cognitive resources in response to expectations and feedback. Here we explored how frontal networks respond in a gambling paradigm in which uncertainty was manipulated to increase demands for cognitive control. In one experiment, pupil diameter covaried with uncertainty during decision making and with the degree to which subsequent outcomes violated reward expectations. In a second experiment, fMRI showed that both uncertainty and unexpected outcomes modulated activation in a network of frontal regions. Thus, the frontal network supports multiple phases of the decision-making process including information regarding reward uncertainty and reward outcome. In contrast, striatal activation only tracked reward delivery, suggesting a distinct reward pathway that might, under certain circumstances, oppose the frontal network. These results are consistent with the interpretation that reward signals may bias recruitment of frontal networks that are linked to allocation of cognitive resources.

The current experiment examined whether adjusting-amount and adjusting-delay procedures provide equivalent measures of discounting. Pigeons' discounting on the two procedures was compared using a within-subject yoking technique in which the indifference point (number of pellets or time until reinforcement) obtained with one procedure determined the value of the corresponding variable in the yoked condition with the other procedure. Behavior on each procedure was well described by a hyperbolic discounting function. Results revealed no systematic differences in the degree of discounting as measured by the discounting rate parameter of the hyperbola in Experiment 1, which used 20-mg pellets. These results were replicated in Experiment 2 using smaller, 14-mg pellets, which potentially yield more precise measurement of indifference points on the adjusting-amount procedure. The finding that estimates of the k parameter in the hyperbolic discounting function obtained with one procedure did not differ systematically from estimates obtained from the same subjects with the other procedure represents strong support for the hypothesis that the same process underlies the discounting of delayed rewards on both adjusting-amount and adjusting-delay procedures.

We compared temporal and probability discounting of a nonconsumable reward (money) and three directly consumable rewards (candy, soda, and beer). When rewards were delayed, monetary rewards were discounted less steeply than directly consumable rewards, all three of which were discounted at equivalent rates. When rewards were probabilistic, however, there was no difference between the discounting of monetary and directly consumable rewards. It has been reported that substance abusers discount delayed drug rewards more steeply than delayed money, but this difference may reflect special characteristics of drugs or drug abusers, or it may reflect a general property of consumable rewards. The present findings suggest that abused substances (like beer) share the properties of other directly consumable rewards, whereas delayed monetary rewards are special because they are fungible, generalized (conditioned) reinforcers.

The present experiments extend the temporal discounting paradigm from choice between an immediate and a delayed reward to choice between 2 delayed rewards: a smaller amount of money available sooner and a larger amount available later. Across different amounts and delays, the data were consistently well described by a hyperbola-like discounting function, and the degree of discounting decreased systematically as the delay to the sooner reward increased. Three theoretical models (the elimination-by-aspects, present-value comparison, and common-aspect attenuation hypotheses) were evaluated. The best account of the data was provided by the common-aspect attenuation hypothesis, according to which the common aspect of the choice alternatives (i.e., the time until the sooner reward is available) receives less weight in the decision-making process.

When choosing between delayed or uncertain outcomes, individuals discount the value of such outcomes on the basis of the expected time to or the likelihood of their occurrence. In an integrative review of the expanding experimental literature on discounting, the authors show that although the same form of hyperbola-like function describes discounting of both delayed and probabilistic outcomes, a variety of recent findings are inconsistent with a single-process account. The authors also review studies that compare discounting in different populations and discuss the theoretical and practical implications of the findings. The present effort illustrates the value of studying choice involving both delayed and probabilistic outcomes within a general discounting framework that uses similar experimental procedures and a common analytical approach., (((c) 2004 APA, all rights reserved))

Temporal discounting refers to the decrease in the present, subjective value of a reward as the time to its receipt increases. Results from humans have shown that a hyperbola-like function describes the form of the discounting function when choices involve hypothetical monetary rewards. In addition, magnitude effects have been reported in which smaller reward amounts are discounted more steeply than larger amounts. The present research examines the cross-species generality of these findings using real rewards, namely food pellets, with both pigeons and rats. As with humans, an adjusting amount procedure was used to estimate the amount of immediate reward judged equal in value to a delayed reward. Different amounts of delayed food rewards (ranging from 5 to 32 pellets in pigeons and from 5 to 20 pellets in rats) were studied at delays varying from 1 s to 32 s. A simple hyperbola, similar to the hyperbola-like mathematical function that describes the discounting of hypothetical monetary rewards in humans, described the discounting of food rewards in both pigeons and rats. These results extend the generality of the mathematical model of discounting. Rates of discounting delayed food rewards were higher for pigeons than for rats. Unlike humans, however, neither pigeons nor rats showed a reliable magnitude effect: Rate of discounting did not vary systematically as a function of the amount of the delayed reward.