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Discounting of delayed reinforcers: Measurement by questionnaires versus operant choice procedures
Abstract
The ability of a reinforcer to maintain behavior decreases as a hyperbolic function of its delay. This discounted value can help explain impulsivity defined as the choice of an immediate, small reinforcer over a delayed, large reinforcer. Human operant studies using consumable reinforcers such as videos have found impulsivity with delays under 1 min. However, measures of discounting rates using questionnaires that describe hypothetical amounts of monetary reinforcers and delays of days, months, or years have found discounting rates that are much too low to explain impulsive choice in operant procedures. A comparison of discounting rates across questionnaire and operant studies indicates that questionnaires produce slower discounting because of the absence of both reinforcement and consumption processes. Combining reinforcement with questions about future reinforcers could facilitate the integration of questionnaire research into a behavioral framework.
... There have been numerous attempts to develop screening measures to identify the potential presence of steep discounting rate (e.g.,Navarick, 2004). To evaluate the discounting of delayed rewards, the most commonly used traditional discounting measure presents an individual with a series of pairs of hypothetical choices: participants choose between a smaller, more immediate alternative and a larger, more delayed alternative (e.g.,Green & Myerson, 2004;Rachlin et al., 1991). ...
... As has been seen, typical discounting measurement methods are somehow different from the usual forms of psychometric assessment. The presumption that questionnaire with (usually dozens) pairs of choices reflect behavioral processes requires critical examination (Navarick, 2004). Although widely used, some researchers have argued that the traditional discounting measure suffers from a number of practical problems. ...
... Obviously, every researcher who has used hypothetical rewards has questioned the validity of their procedures, noting that choices made between these outcomes may not accurately reflect the choices between real outcomes (Madden et al., 2004). The additional problem with traditional discounting measures using pairs of hypothetical choices is that the accuracy of measurement may be compromised due to task fatigue or boredom as a result of the many choices required, e.g., 100 or more (Navarick, 2004). For these and other reasons, resent research was devoted to constructing a tool different from traditional means of measuring the discounting rate consisting of pairs of hypothetical choices (Malesza & Ostaszewski, in press). ...
Recent research introduced the Discounting Inventory that allows the measurement of individual differences in the delay, probabilistic, effort, and social discounting rates. The goal of this investigation was to determine several aspects of the reliability of the Discounting Inventory using the responses of 385 participants (200 non-smokers and 185 current-smokers). Two types of reliability are of interest. Internal consistency and test-retest stability. A secondary aim was to extend such reliability measures beyond the non-clinical participant. The current study aimed to measure the reliability of the DI in a nicotine-dependent individuals and non-nicotine-dependent individuals. It is concluded that the internal consistency of the DI is excellent, and that the test-retest reliability results suggest that items intended to measure three types of discounting were likely testing trait, rather than state, factors, regardless of whether “non-smokers” were included in, or excluded from, the analyses (probabilistic discounting scale scores being the exception). With these cautions in mind, however, the psychometric properties of the DI appear to be very good.
... There have been numerous attempts to develop screening measures to identify the potential presence of steep discounting rate (e.g.,Navarick, 2004;Smith & Hantula, 2008). To evaluate the discounting of delayed rewards, the most commonly used traditional discounting measure presents an individual with a series of pairs of hypothetical choices: participants choose between a smaller, more immediate alternative and a larger, more delayed alternative (e.g.,Green & Myerson, 2004;Rachlin et al., 1991). ...
... As has been seen, typical discounting measurement methods are somehow different from the usual forms of psychometric assessment. Although widely used, some researchers have argued that the traditional discounting measure suffers from a number of practical problems (Navarick, 2004). Obviously, every researcher who has used hypothetical rewards has questioned the validity of their procedures, noting that choices made between these outcomes may not accurately reflect the choices between real outcomes (Madden et al., 2004). ...
... Obviously, every researcher who has used hypothetical rewards has questioned the validity of their procedures, noting that choices made between these outcomes may not accurately reflect the choices between real outcomes (Madden et al., 2004). The additional problem with traditional discounting measures using pairs of hypothetical choices is that the accuracy of measurement may be compromised due to task fatigue or boredom as a result of the many choices required, e.g., 100 or more (Navarick, 2004). For these and other reasons, resent research was devoted to constructing a tool different from traditional means of measuring the discounting rate consisting of pairs of hypothetical choices (Malesza & Ostaszewski, in press). ...
The Discounting Inventory (DI), originally developed in polish language, allows the measurement of individual differences in the delay, probabilistic, effort, and social discounting rates. The present study attempted to validate the DI’s psychometric properties using German university students and to compare the results to those from a sample of Polish university students. Over four hundred participants completed the DI and traditional discounting measures. A confirmatory factor analyses indicated that the original four-factor model of the DI provided an excellent fit for the German data and internal consistency was high. These outcomes were similar, if not superior, to those from the Polish sample. DI scores strongly correlated with traditional discounting measures scores in both samples, replicating previous results. These findings indicate that the DI is a valid measure for use in a sample from another cultural setting, which is potentially useful to both researchers and practitioners.
... This is compatible with the lack of self-control responses observed in children (Logue, Forzano, & Ackerman, 1996) and adults (Logue & King, 1991), when tested in intertemporal choice tasks with primary reinforcers. More generally, a review by Navarick (2004) had already indicated that humans exhibit a remarkably lower delay tolerance in operant tasks, as opposed to their performance with questionnaires (for recent confirmation of that finding, see Jimura, Myerson, Hilgard, Keighley, Braver, & Green, 2011). ...
... The discrepancy in discounting rates observed in Rosati et al. (2007) is not an isolated incident. Previously, Navarick (2004) reported an equally large discrepancy between the discount rates in, respectively, an operant task with cartoon videos as reinforcers (Navarick, 1998;k ¼ 1046.35) and a questionnaire with either real or hypothetical monetary rewards (Johnson & Bickel, 2002; k ¼ 0.0096). Again, it would appear that this discrepancy cannot be accounted for by magnitude effects because of the size the difference: 100,000 times higher in the operant task than in the questionnaire task (for further discussion, see Navarick, 2004, pp. ...
... While lack of correlation in individual performance between two tasks that putatively measure delay discounting is problematic, what matters here is the magnitude of the difference in discount rates across the two tasks. Unfortunately, the authors do not explicitly discuss the magnitude of that discrepancy, but they do note that "liquid rewards tended to lose half their value when delayed for only a minute or less whereas it took a delay of several months for the monetary rewards to lose half their value" (Jimura et al., 2011, p. 258). 2 In all these cases, the discount rates observed in operant tasks were out of scale with those estimated through questionnaires, and this was true both within-subjects (Rosati et al., 2007;Jimura et al., 2011) and between-subjects (Navarick, 2004). 3 As a final consideration, if we take the mean discounting rate parameters of Equation 2 in the Rosati et al. (2007) operant task (see above) and apply it to the choices made in the questionnaire discounting task, then participants should be indifferent between $4.80 now and $100 delivered after a 24-hr delay. ...
Intertemporal choices are typically regarded as indicative of delay discounting. In this view, the degree of behavioral propensity to wait for a reward is attributed to an underlying process of reward devaluation as a function of delay. However, this widespread interpretation overlooks the role that the costs of delay might have in determining intertemporal choices. In this paper I review evidence of a marked discrepancy in intertemporal behavior across different tasks, and argue that the differential costs of delay can account for this anomaly better than alternative explanations. In particular, I characterize two types of delay, waiting versus postponing, examine how they impact behavioral choices across delay discounting tasks, what methodological challenges they present for new experimental paradigms, and what theoretical implications they have for our understanding of intertemporal choice.
... To varying degrees, a number of researchers have questioned the validity of these findings because of their use of hypothetical rewards (e.g., Bickel and Marsch, 2001;Critchfield and Kollins, 2001;Navarick, 2004). For example, Navarick has suggested that when experimenters use prospect choices and hypothetical rewards they are studying an entirely different discounting process than when real rewards that may be immediately consumed are used. ...
... Whether systematic differences in delay discounting would be observed if participants in these studies were given more exposure to the choices arranged in these studies is currently unknown. Navarick (2004) and Madden et al. (2004) have cautioned that there may be an important distinction between potentially real and real rewards (where every choice made results in the delivery of the alternative chosen). Potentially real rewards may not affect behavior in the same way as real rewards, because participants may not treat every reward as if it will actually be delivered. ...
... This failure to detect a difference occurred despite the facts that: (a) participants had prior experience with forced-choice trials at each of the delays at which discounting was assessed in the real-reward condition; (b) participants actually received the consequences of every choice made during the real-reward condition; (c) participants made repeated choices until their decisions were judged to be stable in both conditions. Further, the present study failed to demonstrate a consistent difference between hypothetical and real consumable rewards -conditions across which Navarick (2004) predicted sizeable differences in degree of delay discounting would be observed. The present findings offer additional support for the apparent consensus in the literature (e.g., Johnson and Bickel, 2002;Madden et al., 2003) that human subjects faced with choices involving hypothetical rewards are Fig. 4. Individual subject's present (discounted) values of hypothetical (open symbols) and real (closed symbols) rewards assessed across the subset of delays used in the real-reward condition. ...
Human research in delay discounting has omitted several procedures typical of animal studies: forced-choice trials, consequences following each response, and assessment of stable response patterns. The present study manipulated these procedures across two conditions in which real or hypothetical rewards were arranged. Six college students participated in daily sessions, in which steady-state discounting of hypothetical and real rewards was assessed. No systematic effects of repeated exposure to hypothetical rewards was detected when compared with first day assessments of discounting. Likewise, no systematic effect of reward type (real versus hypothetical) was detected. When combined with previous research failing to detect a difference between hypothetical and potentially real rewards, these findings suggest that assessing discounting of hypothetical rewards in single sessions is a practical and valid procedure in the study of delay discounting.
... These hypothetical, potentially real, and real tasks vary greatly in terms of parameter settings. Therefore, one may wonder whether these tasks measure the same construct, 120,134,135 and whether the same neural circuitries are involved. Hypothetical and potentially real TD tasks yielded similar TD functions, 80,113,119,120,136 and recruited similar brain regions. ...
... Preference reversals refer to observations that individuals may resist the sooner reward when it is not available immediately, but choose it when it is available right away. This observation has been made in several studies 40,73,114,135,[172][173][174] and suggests that people's choices deviate from what would be predicted by economic theory. 175 ...
Temporal reward discounting (TD) refers to the decrease in subjective value of a reward when the delay to that reward increases. In recent years, a growing number of studies on the neural correlates of temporal reward discounting have been conducted. This article focuses on functional magnetic resonance imaging (fMRI) studies on TD in humans. First, we describe the different types of tasks (also from behavioral studies) and the dependent variables. Subsequently, we discuss the evidence for three neurobiological models of TD: the dual-systems model, the single-system model and the self-control model. Further, studies in which nontraditional tasks (e.g., with nonmonetary rewards) were used to study TD are reviewed. Finally, we discuss the neural correlates of individual differences in discounting, and its development across the lifespan. We conclude that the evidence for each of the three neurobiological models of TD is mixed, in that all models receive (partial) support, and several studies provide support for multiple models. Because of large differences between studies in task design and analytical approach, it is difficult to draw a firm conclusion regarding which model provides the best explanation of the neural correlates of temporal discounting. We propose that some components of these models can complement each other, and future studies should test the predictions offered by different models against each other. Several future research directions are suggested, including studying the connectivity between brain regions in relation to discounting, and directly comparing the neural mechanisms involved in discounting of monetary and primary rewards. WIREs Cogn Sci 2013, 4:523-545. doi: 10.1002/wcs.1246 CONFLICT OF INTEREST: The authors have declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website.
© 2013 John Wiley & Sons, Ltd.
... Participants are also usually asked to imagine either receiving a sum of money now, or in a number of days (Paglieri, 2013), then asked to select their preferred option. This methodology has been criticised by several researchers (Navarick, 2004;Paglieri, 2013), who found the rate of discounting to be orders of magnitude lower in questionnaire studies when compared to comparable experiments where participants experience reward delay. Temporal discounting effects may have been grossly underestimated using these methods, with previous work suggesting that reward delays needed to extend over weeks or months to affect behaviour (Kirby, 2009;Kirby and Marakovic, 1996). ...
Designers commonly use gamification to improve the frequency of engagement with apps, but often fail to consider the impact of placement on reward value. As rewards tend to depreciate if delayed (termed temporal discounting), placing a reward further into the future can significantly affect its ability to motivate behaviour. We examine the most effective placement of gamified rewards so as to reduce discounting and to increase the frequency an application is used. In two online studies, users were asked to choose between fictional budget tracking applications that varied in the placement of either monetary (N=70) or gamified (N=70) rewards. In both experiments we found that people more frequently used the application that provided rewards before, rather than after, the task. As predicted by temporal discounting, our work suggests that placing rewards early in the interaction sequence leads to an improvement in the perceived value of that reward, motivating further selection. We discuss the findings in the context of designing effective reward structures to encourage more frequent app engagement.
... These differences may have contributed to the lack of overall difference observed between the individual and group conditions. There is evidence that different methodologies can result in different discount rates (Epstein et al., 2003;Kowal, Yi, Erisman, & Bickel, 2007;Navarick, 2004;Robles & Vargas, 2007. However, the single study to compare paper and computerized binary choice procedures (Smith & Hantula, 2008) found no difference in discount rate, calculated either as k (as in the present study) or as AUC. ...
Temporal discounting assessments measure the reduction in the subjective value of a reward as a function of the delay to that reward, and are correlated with behavior in social dilemma. Among the solutions proposed for defection in social dilemmas is a single individual making the decisions for the group. The present study examined the influence of group context on temporal discounting. Participants completed temporal discounting procedures when the outcomes affected only the individual and when outcomes affected a group of 10, including the individual. Though no overall difference was observed between the individual and group conditions, sex was found to be a moderating variable: Males discounted significantly more when discounting for the individual, but females discounted significantly more when discounting for the group. These results indicate that sex is an important variable when making intertemporal decisions for a group.
... While animal studies have employed primary reinforcers associated with real delays (Freeman et al., 2009Freeman et al., , 2012Green et al., 2004;Richards et al., 1997), most human studies have used hypothetical rewards associated with hypothetical delays (Green et al., 1997;Kollins, 2003;Wittmann et al., 2007). It has been suggested that hypothetical and realtime rewards may not be processed on the same way or degree (Hinvest and Anderson, 2010;Hyten et al., 1994;Navarick, 2004). Some indirect evidence regarding the importance of experiencing the attributes of reinforcers vs. receiving the description of such attributes, comes from studies of risky choice in humans. ...
... In support of the last point, studies that have compared different indices of impulsivity typically find weak correlations (e.g. Evenden, 1999;Lane et al., 2003;Navarick, 2004;Reynolds et al., 2006). For instance, Reynolds and his colleagues (2006) measured the correlations among some 14 different measures of impulsivity, including delay discounting. ...
Individuals who smoke cigarettes regularly but do not become dependent on them provide a unique opportunity for studying the factors that inhibit drug dependence. Previous research on this population, sometimes referred to as 'cigarette chippers', showed that they did not differ from regular smokers in terms of smoking topography (e.g. puff number and duration) and circulating nicotine levels, but that they did show more self-control according to answers on a questionnaire. We evaluated the generality of this finding using a behavioral choice procedure. The participants were undergraduate students (n=71), who were regular smokers, chippers, or nonsmokers. In the choice procedure, one option was a smaller but sooner amount of money, and the other option was a larger but delayed amount of money. Under these conditions, preference for the sooner smaller amount implies that the later larger monetary amounts were discounted. It is widely assumed that the rate of discounting provides an operational definition of impulsivity. In one version of the procedure, the money was hypothetical. In a second version, each choice had a chance of producing an actual monetary outcome. When there was an actual monetary outcome, regular smokers were more likely to choose the sooner but smaller monetary option than chippers and nonsmokers. For all participants, the rate of discounting decreased as the magnitude of the monetary outcomes increased, and for smokers and chippers the differences in discount rates in the two versions of the delayed outcome procedure were the same. These findings are consistent with the view that chippers are less impulsive than smokers. Quantitative aspects of these findings led to the hypothesis that discount rates decrease as a negative power function of the monetary value of the options. This result establishes an analogy between delay discounting experiments and psychophysical experiments. Results from two earlier studies support the analogy.
Principles of economics predict that the costs associated with obtaining rewards can influence choice. When individuals face choices between a smaller, immediate option and a larger, later option, they often experience opportunity costs associated with waiting for delayed rewards because they must forego the opportunity to make other choices. We evaluated how reducing opportunity costs affects delay tolerance in capuchin monkeys. After choosing the larger option, in the High cost condition, subjects had to wait for the delay to expire, whereas in the Low cost different and Low cost same conditions, they could perform a new choice during the delay. To control for the effect of intake rate on choices, the Low cost same condition had the same intake rate ratio as the High cost condition. We found that capuchins attended both to intake rates and to opportunity costs. They chose the larger option more often in the Low cost different and Low cost same conditions than in the High cost condition, and more often in the Low cost different condition than in the Low cost same condition. Understanding how non-human primates represent and use costs in making decisions not only helps to develop theoretical frameworks to explain their choices but also addresses similarities with and differences from human decision-making. These outcomes provide insights into the origins of human economic behaviour.
This article is part of the theme issue ‘Existence and prevalence of economic behaviours among non-human primates’.
Los resultados encontrados en situaciones de elección
entre animales humanos y no humanos son, en algunos
casos, contradictorios. Se han propuesto dos posibles
explicaciones: (i) los procesos de elección son diferentes
en animales humanos y no humanos o (ii) los
procedimientos utilizados para el estudio de la elección
en unos y otros no son comparables. Particularmente,
en humanos se observan mayores tiempos de respuesta
a medida que se incrementa el número de alternativas
que constituyen el contexto de elección. Esto ha sido
interpretado como evidencia a favor de un proceso de
comparación entre las alternativas presentadas. Sin embargo,
estudios recientes con estorninos han encontrado
resultados opuestos. Para dar razón de estos resultados
se ha propuesto el Modelo de Elección Secuencial, que
no asume la existencia de un proceso de comparación y
permite realizar predicciones concretas en situaciones de
elección momento a momento. Se diseñó una tarea equivalente
a las empleadas con animales no humanos para
su presentación en humanos. Los resultados apoyaron
parcialmente las predicciones del Modelo de Elección
* Correspondencia. Correo electrónico: oscargl@cencar.udg.mx
Cómo citar este artículo: García-Leal, Ó., & Rodríguez-Macías, E. L. (2018). Análisis empírico del Modelo de Elección
Secuencial en humanos. Avances en Psicología Latinoamericana, 36(1), 139-153. doi: http://dx.doi.org/10.12804/revistas.
urosario.edu.co/apl/a.4869
Secuencial, si bien no permiten descartar la existencia
de un mecanismo de comparación en humanos.
The purpose of the project was to develop the Discounting Inventory (DI), a measure of individual differences in delay, probability, effort, and social discounting, all related to behavioral impulsivity. Over 400 items relating to four types of discounting were generated. Next, a study followed by a series of psychometric analyses of data obtained from a group of 2843 individuals was conducted. Principal Component Analysis yielded a four-factor structure of data, reflecting the four types of discounting. The results of Confirmatory Factor Analysis showed good fit of the four-factor model to data. Through several iterations of retaining and deleting items on the basis of their component loadings, item intercorrelations, and contribution to coefficient alphas, the total number of items was reduced to 48. The final 48-item version of the inventory has satisfactory psychometric characteristics, including Cronbach’s alpha and test–retest stability. In addition, significant correlations were observed between the DI and traditional discounting instruments, suggesting that the DI measures a construct similar to the behavioral discounting process. The development of the tool was based on the assumption that discounting is a personality trait. However, the present data suggest that discounting may reflect more a state than trait function.
College students exhibited impulsivity if, in the first of 2 sessions, they consistently chose an immediate, small reinforcer (15-s cartoon video followed by 75 s of waiting) over a delayed, large reinforcer (55-s prereinforcer delay, 25-s video, 10 additional s of waiting), or self-control if they showed the opposite preference. Previously, Navarick (2001 ) found that informing impulsive participants in Session 2 that the viewing time was longer on their nonpreferred schedule reduced impulsive choice to about 50; informing self-controlled participants that the video started sooner on their nonpreferred schedule had no effect. In addition to facilitating discrimination between reinforcers, the instructions to impulsive participants could have implied a request to choose the indicated schedule (a demand characteristic) or that the nonpreferred schedule was somehow more advantageous. Effects of these potentially implicit instructions were assessed by presenting them as explicit instructions to determine if they again produced a decrease in impulsive choices in impulsive participants and no change in self-controlled participants. In contrast to the previous pattern, impulsive and self-controlled participants conformed similarly to the experimenter's stated schedule preference, and showed similar, variable preferences in response to the general schedule characterization. The previous instructions reduced impulsivity by facilitating discrimination between the large and small reinforcers and not by conveying these implicit messages.
For much of his career, B. F. Skinner displayed the optimism that is often attributed to behaviorists. With time, however, he became less and less sanguine about the power of behavior science to solve the major problems facing humanity. Near the end of his life he concluded that a fair consideration of principles revealed by the scientific analysis of behavior leads to pessimism about our species. In this article I discuss the case for Skinner's pessimism and suggest that the ultimate challenge for behavior analysts today is to prove Skinner wrong.
Nonhuman animals steeply discount the future, showing a preference for small, immediate over large, delayed rewards [1–5]. Currently unclear is whether discounting functions depend on context. Here, we examine the effects of spatial context on discounting in cotton-top tamarins (Saguinus oedipus) and common marmosets (Callithrix jacchus), species known to differ in temporal discounting [5]. We presented subjects with a choice between small, nearby rewards and large, distant rewards. Tamarins traveled farther for the large reward than marmosets, attending to the ratio of reward differences rather than their absolute values. This species difference contrasts with performance on a temporal task in which marmosets waited longer than tamarins for the large reward. These comparative data indicate that context influences choice behavior, with the strongest effect seen in marmosets who discounted more steeply over space than over time. These findings parallel details of each species’ feeding ecology. Tamarins range over large distances and feed primarily on insects, which requires using quick, impulsive action. Marmosets range over shorter distances than tamarins and feed primarily on tree exudates, a clumped resource that requires patience to wait for sap to exude [6–9]. These results show that discounting functions are context specific, shaped by a history of ecological pressures.
Includes Supplemental data.
Nearly 25% of American adults remain regular smokers. Current smokers may be especially likely to possess characteristics that impair their ability to quit, such as impulsivity. Impulsive individuals may be overly prone to smoke because they are particularly drawn to rewarding stimuli and related cues. The aim of this study was to test the hypothesis that more impulsive smokers are more responsive to cigarette cues than other smokers.
In a repeated measures design, 60 euthymic, adult smokers (50% female) were exposed to a smoking cue and a neutral cue in two experimental sessions. Cue reactivity was operationalized as changes in cigarette craving and preference for immediate vs delayed smoking after cue exposure.
Impulsivity predicted a heightened craving response to both cues but particularly the smoking cue (t [161] = 3.21, p = 0.002). Smokers with high levels of impulsivity exhibited a greater preference for immediate rewards over larger, delayed rewards in terms of both hypothetical (t [58] = 5.99, p = 0.001) and actual (z = 3.02, p = 0.003) rewards.
These data suggest that increased reactivity to environmental smoking cues contributes to the link between impulsivity and smoking.
The present, subjective value of a delayed reward is a decreasing function of the duration of the delay. This phenomenon is
termed temporal discounting. To determine whether the amount of the reward influences the rate of temporal discounting, we
had subjects choose between immediate and delayed hypothetical rewards of different amounts (100,100, 2,000, 25,000, and25,000, and 100,000
delayed rewards). As predicted by psychological models of the choice process, hyperbolic functions described the decrease
in the subjective value of the delayed reward as the time until its receipt was increased (R2s from .86 to .99). Moreover,
hyperbolic functions consistently provided more accurate descriptions of the data than did exponential functions predicted
by an economic model of discounted utility. Rate of discounting decreased in a negatively accelerated fashion as the amount
of the delayed reward increased, leveling off by approximately $25,000. These findings are interpreted in the context of different
psychological models of choice, and implications for procedures to enhance self-control are discussed.
In a choice among assured, familiar outcomes of behavior, impulsiveness is the choice of less rewarding over more rewarding alternatives. Discussions of impulsiveness in the literature of economics, sociology, social psychology, dynamic psychology and psychiatry, behavioral psychology, and "behavior therapy" are reviewed. Impulsiveness seems to be best accounted for by the hyperbolic curves that have been found to describe the decline in effectiveness of rewards as the rewards are delayed from the time of choice. Such curves predict a reliable change of choice between some alternative rewards as a function of time. This change of choice provides a rationale for the known kinds of impulse control and relates them to several hitherto perplexing phenomena: behavioral rigidity, time-out from positive reinforcement, willpower, self-reward, compulsive traits, projection, boredom, and the capacity of punishing stimuli to attract attention. (31/2 p ref)
Choice responding by adult humans in a discrete-trial task was examined as a function of conditions that manipulated either the delay to point delivery or the delay between points and their exchange for money. In point-delay conditions, subjects chose between an "impulsive" alternative that provided a small amount of points immediately and a "self-control" alternative that provided a larger amount of points delayed by 15, 30, or 60 s. Points were exchanged for money immediately following the session. Subjects preferred the self-control alternative. In exchange-delay conditions, subjects chose between a small amount of points exchangeable for money immediately following the session and a larger amount of points exchangeable for money after 1 day, 3 weeks, or 6 weeks. A self-control preference observed for all subjects in the 1-day exchange-delay condition reversed to exclusive impulsive preference for 4 of the 6 subjects when choice conditions involved exchange delays of 3 or 6 weeks. These results show that human choice is sensitive to the manipulation of exchange delays and that impulsive preference can be obtained with exchange delays on the order of weeks.
The authors discuss the relationship of impulsivity to psychiatric disorders and present selected hypotheses regarding the reasons for these relationships.
Previous research has shown significantly higher levels of impulsivity among patients with conduct disorder, personality disorders, substance use disorders, and bipolar disorder, compared to other psychiatric patients or healthy comparison subjects. A literature review of the theoretical bases of the relationship between these disorders and impulsivity is presented. Measurements of impulsivity and treatment options are discussed in relation to the physiology of impulsivity and the disorders in which it is a prominent feature.
Impulsivity, as defined on the basis of a biopsychosocial approach, is a key feature of several psychiatric disorders. Behavioral and pharmacological interventions that are effective for treating impulsivity should be incorporated into treatment plans for these disorders.
The high comorbidity of impulsivity and selected psychiatric disorders, including personality disorders, substance use disorders, and bipolar disorder, is in a large part related to the association between impulsivity and the biological substrates of these disorders. Before treatment studies on impulsivity can move forward, measures of impulsivity that capture the core aspects of this behavior need to be refined and tested on the basis of an ideologically neutral model of impulsivity.
Participants chose between reinforcement schedules differing in delay of reinforcement (interval between a choice response and onset of a video game) and/or amount of reinforcement (duration of access to the game). Experiment 1 showed that immediate reinforcement was preferred to delayed reinforcement with amount of reinforcement held constant, and a large reinforcer was preferred to a small reinforcer when both were obtainable immediately. Imposing a delay before the large reinforcer produced a preference for the immediate, small reinforcer in 40% of participants. This suggested a limited degree of “impulsivity.” In Experiment 2, unequal delays were extended by equal intervals, the amounts being kept equal. Preference for the shorter delay decreased, an effect that presumably makes possible the “preference reversal” phenomenon in studies of self-control. Overall, the results demonstrate that video game playing can produce useful, systematic data when used as a positive reinforcer for choice behavior in humans.
Participants chose between reinforcement schedules differing in delay and/or duration of noise offset. In Experiment 1 it was found that (1) immediate reinforcement was preferred to delayed reinforcement when amounts (durations) of reinforcement were equal; (2) a relatively large reinforcer was preferred to a smaller one when both reinforcers were obtained immediately; and (3) preference for an immediate, small reinforcer versus a delayed, large reinforcer increased as the delay preceding the large reinforcer increased, a sign of “impulsivity”. In Experiment 2, the schedules differed in amount or delay and equal intervals were added either to the constant parameter or the varied parameter. A shift from virtually exclusive preference to indifference occurred in the latter case but not the former, a result supporting a model of self-control that assumes that the value of a schedule depends on the ratio of amount and delay, and that choice between schedules depends on the ratio of these values.
This paper considers a number of parallels between risky and intertemporal choice. We begin by demonstrating a one-to-one correspondence between the behavioral violations of the respective normative theories for the two domains (i.e., expected utility and discounted utility models). We argue that such violations (or preference reversals) are broadly consistent with three propositions about the weight that an attribute receives in both types of multiattribute choice. Specifically, it appears that: (1) if we add a constant to all values of an attribute, then that attribute becomes less important; (2) if we proportionately increase all values of an attribute, or if we change the sign of an attribute, from positive to negative, then that attribute becomes more important. The generality of these propositions, as well as the constraints they would impose on separable representations of multiattribute preferences, is discussed.
Young adults shopped for music compact disks in a five store simulated Internet mall. In stock probability in all stores was constant at 0.80, but each store was associated with either a 0.5, 2, 4, 8, or 16 second to a feedback message indicating whether a particular disk was in stock or out of stock at that time. Working under a successive choice schedule, in Phase I subjects' behavior was in quantitative concordance with the Delay-Reduction Hypothesis (DRH), and in Phase II, when a changeover delay was added, subjects' behavior conformed more closely to the predictions of the DRH. Hyperbolic discount functions provided the best fit to the data. This study extends the synthesis of foraging theory and operant psychology, known as behavioral ecology, to human consumption in an affluent post-industrial culture, and provides the basis for an experimental analysis of human consumption. Extensions to research in consumer behavior, marketing strategy, and behavior on Internet services are proposed. Copyright © 2000 John Wiley & Sons, Ltd.
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 250. 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.