Temporal Discounting

Actors in competitive environments are bound to decide and act under conditions of uncertainty because they rarely have accurate foreknowledge of how their opponents will respond and when they will respond. Just as a competitor makes a move to improve their standing on a given variable relative to a target competitor, she should expect the latter to counteract with an iterative lagged asymmetric response, that is, with a sequence of countermoves (iteration) that is very different in kind from its trigger (asymmetry) and that will be launched at some unknown point in the future (time lag). The paper explicates the broad relevance of the newly proposed concept of " iterative lagged asymmetric responses " to the social study of temporality and to fields as diverse as intelligence and counterintelligence studies, strategic management, futures studies, military theory, and long-range planning. By bringing out in the foreground and substantiating the observation that competitive environments place a strategic premium on surprise, the concept of iterative lagged asymmetric responses makes a contribution to the never-ending and many-pronged debate about the extent to which the future can be predicted.
DOI: https://doi.org/10.1177/0961463X17752652

Clinic-referred teens (ages 12–19) with ADHD and ODD (N = 101) were compared to community control (CC) teens, equated for age and sex, (N = 39) on a variety of psychological tasks assessing executive functioning (EF), temporal reward discounting, and time estimation and reproduction. A factor analysis reduced the EF measures to three dimensions, representing CPT Inattention, Working Memory, and CPT Inhibition. Results indicated that the ADHD group had significantly more CPT Inattention than the CC group. No differences were found for Working Memory or CPT Inhibition. The ADHD group displayed significantly greater temporal discounting of delayed hypothetical monetary rewards relative to immediate ones and manifested more impaired time reproduction, but not time estimation, than did the CC group. Main effects for level of IQ were found only on the Working Memory factor and largely did not interact with the group factor otherwise. The group differences in CPT Inattention, temporal discounting, and time reproduction were not a function of level of comorbid oppositional defiant disorder, delinquency, or anxiety–depression. Results are reasonably consistent with past research on EF and sense of time in children with ADHD and extend these findings to the adolescent age group. Problems with working memory and CPT inhibition found in prior studies of children with ADHD, however, were not evident here, perhaps owing to age-related improvements or insufficient task difficulty.

We examine how individual differences in the consideration of future consequences impact trait self-control, and temporal discounting under conditions of ego-depletion. Study 1 (N = 986) reveals that the CFC scale contains two underlying factors, which can be labeled the CFC-Immediate (CFC-I) and CFC-Future (CFC-F) sub-scales. Supporting the distinction between the two sub-scales, Study 2 (N = 147) shows that lower levels of trait self-control are best predicted by higher levels of CFC-I (not CFC-F), while Study 3 (N = 104) reveals that ego-depletion leads to more temporal discounting only among those high in CFC-I. Future use of the two sub-scales is encouraged.

Three studies examined the relationship between individual differences in the consideration of future consequences (CFC; Strathman, and fiscal responsibility. In Studies 1 and 2, low levels of CFC were associated with high levels of self-reported impulsive buying tendencies and temporal discounting . In Study 3, participants allocated a monetary windfall among four options (credit card debt, savings, purchase, trip) under low and high debt levels. Results revealed that those faced with high levels of debt and low in CFC directed money away from options maximizing long-term interests toward more short-term purchase alternatives; debt level did not have a significant effect on the way people high in CFC allocated their windfall.

Economic models of addiction typically posit intertemporal dependencies in the consumption of addictive goods, although the models differ regarding the structure of the dependencies. Addictions are often associated with multiple attempts to quit, usually successfully for short periods of time, accompanied by eventual relapse. This standard life course of addiction illustrates the role that attitudes to risk over time may play in explaining addictive behaviour. While researchers have paid attention to the atemporal risk attitudes of addicts, no prior research has investigated the intertemporal risk attitudes of addicts. Yet measures of risk attitudes at a point in time logically need have no relation at all with risk attitudes over time. Focusing on smoking behaviour, we undertake a natural first step of comparing experimentally elicited intertemporal risk preferences, along with atemporal risk preferences and time preferences, among cohorts of people who have not been addicted, people who are current addicts, and people who are former addicts. From the resulting data we estimate a structural model of intertemporal risk preferences jointly with a rank-dependent utility model of atemporal risk and a quasi-hyperbolic model of time preferences. The intertemporal risk preferences of our sample exhibit significant heterogeneity and, contrary to the assumption employed by standard economic models of addiction, smokers do not exhibit intertemporal risk seeking behaviour. Instead, our sample is characterised by high levels of intertemporal risk aversion which varies by smoking intensity and smoking severity in men, but not in women. Our results highlight the role that intertemporal risk attitudes, together with atemporal risk attitudes and discounting behaviour, play in the aetiology of addiction.

Aims Delay reward discounting (DRD) measures the degree to which a person prefers smaller rewards soon or larger rewards later. People who smoke have been shown to have higher DRD. There are several ways of measuring DRD, and the method used might influence the association between smoking and DRD. The key differences are the order in which the items are presented, the delays used and the magnitude of the delayed amount. Setting An international online study running from September 2010 to June 2011. Participants A total of 9454 individuals; 38% male, mean age = 23.1 years. Design and measurements Users completed a multi-item DRD task. They were randomly presented the immediate rewards in an ascending, descending or randomized order. The delays were between 1 week and 5 years. The delayed amounts were $1000 for all delays, and $100 for 1 month. Users also self-reported their smoking status. Findings A hyperbolic DRD function fitted better than an exponential function. There were differences in the derived DRD function based on methodology used; items presented in a randomized order, longer delays and smaller rewards showed steeper discounting. However, these did not interact with smoking status, as for all methodologies used daily smokers showed the steepest discounting, followed by non-daily smokers, then non-smokers. Conclusions Smokers discount future consequences more than non-smokers, irrespective of which measurement is used, but variations in method lead to different estimates that are not comparable between experiments.

Many proposed activities for mitigating global warming in the land-use change and forestry (LUCF) sector differ from measures to avoid fossil fuel emissions because carbon (C) may be held out of the atmosphere only temporarily. In addition, the timing of the effects is usually different. Many LUCF activities alter C fluxes to and from the atmosphere several decades into the future, whereas fossil fuel emissions avoidance has immediate effects. Non-CO 2 greenhouse gases (GHGs), which are an important part of emissions from deforestation in low-latitude regions, also pose complications for comparisons between fossil fuel and LUCF, since the mechanism generally used to compare these gases (global warming potentials) assumes simultaneous emissions. A common numeraire is needed to express global warming mitigation benefits of different kinds of projects, such as fossil fuel emissions reduction, C sequestration in forest plantations, avoided deforestation by creating protected areas and through policy changes to slow rates of land-use changes such as clearing. Megagram (Mg)-year (also known as 'ton-year') accounting provides a mechanism for expressing the benefits of activities such as these on a consistent basis. One can calculate the atmospheric load of each GHG that will be present in each year, expressed as C in the form of CO 2 and its instantaneous impact equivalent contributed by other gases. The atmospheric load of CO 2 -equivalent C present over a time horizon is a possible indicator of the climatic impact of the emission that placed this load in the atmosphere. Conversely, this index also provides a measure of the benefit of not producing the emission. One accounting method compares sequestered CO 2 in trees with the CO 2 that would be in the atmosphere had the sequestration project not been undertaken, while another method (used in this paper) compares the atmospheric load of C (or equivalent in non-CO 2 GHGs) in both project and no-project scenarios. Time preference, expressed by means of a discount rate on C, can be applied to Mg-year equivalence calculations to allow societal decisions regarding the value of time to be integrated into the system for calculating global warming impacts and benefits. Giving a high value to time, either by raising the discount rate or by shortening the time horizon, increases the value attributed to temporary sequestration (such as many forest plantation projects). A high value for time also favors mitigation measures that have rapid effects (such as slowing deforestation rates) as compared to measures that only affect emissions years in the future (such as creating protected areas in countries with large areas of remaining forest). Decisions on temporal issues will guide mitigation efforts towards options that may or may not be desirable on the basis of social and environmental effects in spheres other than global warming. How sustainable development criteria are incorporated into the approval and crediting systems for activities under the Kyoto Protocol will determine the overall environmental and social impacts of pending decisions on temporal issues.

In four studies, we show that people who anticipate more personal change over time give more to others. We measure and manipulate participants’ beliefs in the persistence of the defining psychological features of a person (e.g., his or her beliefs, values, and life goals) and measure generosity, finding support for the hypothesis in three studies using incentive-compatible charitable donation decisions and one involving hypothetical choices about sharing with loved ones.

This white paper explores ways to counter temporal discounting and to promote long-term thinking by engaging emotions. From the enhancement of emotional regulation to the activation of transcendent emotions, this paper seeks to provide an initial roadmap for the optimal integration of emotions into the temporal decision-making process. Transgenerational empathy and awe are specifically identified as emotions that can orient people toward a broader temporal perspective.

Many aspects of the calculation of the impacts of greenhouse gas (GHG) emissions and the costs and benefits of possible response options are highly sensitive to the way in which time preference is incorporated into the computations. The Intergovernmental Panel on Climate Change (IPCC) used global warming potentials (GWPs) to standardize inputs of different gases with differing radiative forcings and atmospheric lifetimes; in the results emphasized by the IPCC's Second Assessment Report, a 100-year time horizon and no discounting is used, and this has been adopted by the Kyoto Protocol for use in the first commitment period (2008)(2009)(2010)(2011)(2012). Here an alternative unified index is proposed that assigns explicit weights to the interests of different generations. In contrast to discounting (including the zero discount rate used by the IPCC), the generationally weighted index forces policy makers to face the moral assumptions that underlie their choices related to global warming. : S 0 9 2 1 -8 0 0 9 ( 0 2 ) 0 0 0 0 4 -6 P.M. Fearnside / Ecological Economics 41 (2002) 21-31

Background: Unhealthy behaviors (eg, poor food choices) contribute to obesity and numerous negative health outcomes, including multiple types of cancer and cardiovascular and metabolic diseases. To promote healthy food choice, diet interventions should build on the dual-system model to target the regulation and reward mechanisms that guide eating behavior. Episodic future thinking (EFT) has been shown to strengthen regulation mechanisms by reducing unhealthy food choice and temporal discounting (TD), a process of placing greater value on smaller immediate rewards over larger future rewards. However, these interventions do not target the reward mechanisms that could support healthy eating and strengthen the impact of EFT-anchored programs. Increasing positive affect (PosA) related to healthy food choices may target reward mechanisms by enhancing the rewarding effects of healthy eating. An intervention that increases self-regulation regarding unhealthy foods and the reward value of healthy foods will likely have a greater impact on eating behavior compared with interventions focused on either process alone.

I argue that the use of a social discount rate to assess the costs and benefits of policy responses to climate change is unhelpful and misleading. I consider two lines of justification for discounting, one ethical and the other economic, connected to the two terms of the standard formula for the discount rate. Concerning the former, I examine some arguments recently put forward by Joseph Heath and others for a "pure rate of time preference " and conclude that they fail to overcome standard ethical arguments for temporal neutrality. Concerning the latter, I consider whether the standard economic rationale for discounting, based on the diminishing marginal utility of consumption, is relevant to the specific costs and benefits at stake in climate policy. I argue that it is not, since the unusually long time horizons and nature of the costs and benefits in the climate context mean that a great many of the idealizing assumptions required by this economic rationale do not adequately approximate the underlying reality. The unifying theme of my objections is that all extant rationales for time discounting, both ethical and economic, justify it only as a proxy for normative concerns that have no intrinsic connection to the passage of time, and that in consequence, for any proposed application of a discount rate to ethical or public policy questions, it must be asked whether that approximation is useful to the case at hand. Where it is not, other means must be found to represent the concerns that motivate discounting, and in the concluding section I sketch such an alternative for the case of climate change.

Delay discounting was examined in light smokers (10 or fewer cigarettes per day) and compared with previously published delay discounting data for heavy and never smokers. Participants evaluated several hypothetical outcomes: money gains and loses ($10, $100, and $1,000), health gains and losses (durations of improved and impoverished health subjectively equivalent to $1,000), cigarette gains and losses (amounts subjectively equivalent to $1,000), and potentially real rewards ($10 and $100). Light smokers discounted money significantly more than never smokers, but light smokers did not differ from heavy smokers. The 3 groups did not statistically differ in discounting of health consequences. Similarly, the 2 smoking groups were not found to differ in discounting of cigarettes. Like heavy smokers, light smokers discounted cigarettes significantly more than money and health. Several significant, positive correlations were found between smoking rate and various discounting measures in the heavy smokers but not in the light smokers. Several previous findings were replicated, helping to validate the present results: the sign effect (greater discounting of gains than losses), the magnitude effect (greater discounting of smaller rewards), reliability of discounting measures over time, and the consistency of hypothetical and potentially real rewards. These data suggest that even moderate levels of drug use may be associated with high delay discounting levels.

Animals often aid others without gaining any immediate benefits. Although these acts seem to reduce the donor's fitness, they are only apparently altruistic. Donors typically help because they or their kin receive future benefits or avoid costly punishment. Reciprocal altruism – alternating the roles of donor and recipient – has been a well-studied form of cooperation among non-kin because of its intuitive appeal in explaining human cooperation. Despite immense theoretical interest, little empirical evidence substantiates the biological importance of reciprocal altruism in non-human animals. We propose that this is because psychological mechanisms constrain its application in cooperative contexts. In particular, we contend that cognitive limitations such as temporal discounting, numerical discrimination and memory make reciprocity difficult for animals.

Temporal discounting (TD), the preference for earlier, smaller rewards over delayed, larger rewards, is a pervasive phenomenon that covaries with Big Five personality traits and Intelligence (IQ). This study provides novel insight by identifying correlates for IQ and Extraversion in the neural representation of TD preferences. An intertemporal choice task was employed, where offers were sequentially presented, distinguishing between one evaluation phase (first offer is presented) and one comparison phase (second offer is presented and values are compared). IQ correlated with responses of caudate nucleus to the subjective values of the offers, suggesting a role of cognitive abilities in modulating reward responses. Extraversion correlated with the strength of functional connectivity of a reward evaluation network centered on ventromedial prefrontal cortex.

The tendency to make unhealthy choices is hypothesized to be related to an individual's temporal discount rate, the theoretical rate at which they devalue delayed rewards. Furthermore, a particular form of temporal discounting, hyperbolic discounting, has been proposed to explain why unhealthy behavior can occur despite healthy intentions. We examine these two hypotheses in turn. We first systematically review studies which investigate whether discount rates can predict unhealthy behavior. These studies reveal that high discount rates for money (and in some instances food or drug rewards) are associated with several unhealthy behaviors and markers of health status, establishing discounting as a promising predictive measure. We secondly examine whether intention-incongruent unhealthy actions are consistent with hyperbolic discounting. We conclude that intention-incongruent actions are often triggered by environmental cues or changes in motivational state, whose effects are not parameterized by hyperbolic discounting. We propose a framework for understanding these state-based effects in terms of the interplay of two distinct reinforcement learning mechanisms: a " model-based " (or goal-directed) system and a " model-free " (or habitual) system. Under this framework, while discounting of delayed health may contribute to the initiation of unhealthy behavior, with repetition, many unhealthy behaviors become habitual; if health goals then change, habitual behavior can still arise in response to environmental cues. We propose that the burgeoning development of computational models of these processes will permit further identification of health decision-making phenotypes.

I argue that the use of a social discount rate to assess the costs and benefits of policy responses to climate change is unhelpful and misleading. I consider two lines of justification for discounting, one ethical and the other economic, connected to the two terms of the standard formula for the discount rate. Concerning the former, I examine some arguments recently put forward by Joseph Heath and others for a " pure rate of time preference " and conclude that they fail to overcome standard ethical arguments for temporal neutrality. Concerning the latter, I consider whether the standard economic rationale for discounting, based on the diminishing marginal utility of consumption, is relevant to the specific costs and benefits at stake in climate policy. I argue that it is not, since the unusually long time horizons and nature of the costs and benefits in the climate context mean that a great many of the idealizing assumptions required by this economic rationale do not adequately approximate the underlying reality. The unifying theme of my objections is that all extant rationales for time discounting, both ethical and economic, justify it only as a proxy for normative concerns that have no intrinsic connection to the passage of time, and that in consequence, for any proposed application of a discount rate to ethical or public policy questions, it must be asked whether that approximation is useful to the case at hand. Where it is not, other means must be found to represent the concerns that motivate discounting, and in the concluding section I sketch such an alternative for the case of climate change.

How does the anticipated connectedness between one’s current and future identity help explain impatience in intertemporal preferences? The less consumers are closely connected psychologically to their future selves, the less willing they will be to forgo immediate benefits in order to ensure larger deferred benefits to be received by that future self. When consumers’ measured or manipulated sense of continuity with their future selves is lower, they accept smaller-sooner rewards, wait less in order to save money on a purchase, require a larger premium to delay receiving a gift card, and have lower long-term discount rates.

L’operazione economica di discounting ci serve, come abbiamo visto, per attualizzare le grandezze
economiche future. Nel momento in cui in un paese si cerca di attuare una politica economica è
inevitabile che si cerchi di comprendere quale possa essere l’effetto della stessa sulle generazioni
future. Ed è così anche per le questioni di gestione delle risorse e, come si nota nella lettura della
Stern Review, anche nel caso del cambiamento climatico. Queste politiche sono anche chiamate
scelte intertemporali, proprio a sottolineare l’importanza del tempo e delle generazioni che
verranno. Ma non solo. Il discounting è un’operazione molto complessa che nasce
dall’aggregazione di alcuni parametri economici e tiene conto di una serie di fattori. Vediamone
brevemente la formula.
.

Intertemporal choices involve decisions between outcomes
that are available at different times in the future. Organisms
face these types of choices quite frequently, from natural
history tradeoffs to foraging decisions, mate choice, parental
investment, and cooperative dilemmas. The ever-present
nature of intertemporal choices makes them of interest to a
broad range of disciplines. The economic perspective
generates models of optimal temporal tradeoffs. The
psychological perspective explores the cognitive mechanisms
used in intertemporal choice. The evolutionary perspective
investigates the adaptive value of trading off present and
future benefits. Together, these approaches can provide a
more complete understanding of the balance between
patience and impulsivity.

People tend to attach less value to a good if they know a delay will occur before they obtain it. For example, people value receiving $100 tomorrow more than receiving $100 in 10 years. We explored one reason for this tendency (due to Parfit, 1984): In terms of psychological properties, such as beliefs, values, and goals, the decision maker is more closely linked to the person (his or her future self) receiving $100 tomorrow than to the person receiving $100 in 10 years. For this reason, he or she prefers his or her nearer self to have the $100 rather than his or her more remote self. Studies 1 and 2 showed that the greater the rated psychological connection between 2 parts of a participant's life, the less he or she discounted future monetary and nonmonetary benefits (e.g., good days at work) over that interval. In Studies 3-5, participants read about characters who undergo large life-changing (and connectedness-weakening) events at different points in their lives and then made...

Some people find it more difficult to delay rewards than others. In three experiments, we tested a "future selfcontinuity" hypothesis that individual differences in the perception of one's present self as continuous with a future self would be associated with measures of saving in the laboratory and everyday life. Higher future self-continuity (assessed by a novel index) predicted reduced discounting of future rewards in a laboratory task, more matches in adjectival descriptions of present and future selves, and greater lifetime accumulation of financial assets (even after controlling for age and education). In addition to demonstrating the reliability and validity of the future self-continuity index, these findings are consistent with the notion that increased future self-continuity might promote saving for the future.

Global warming mitigation calculations require consistent procedures for handling time in order to compare 'permanent' gains from energy-sector mitigation options with 'impermanent' gains from many forest-sector options. A critical part of carbon accounting methodologies such as those based on 'ton-years' (the product of the number of tons of carbon times the number of years that each ton is held out of the atmosphere) is definition of a time horizon, or the time period over which carbon impacts and benefits are considered. Here a case is made for using a time horizon of 100 years. This choice avoids distortions created by much longer time horizons that would lead to decisions inconsistent with societal behavior in other spheres; it also avoids a rapid increase in the implied value of time if horizons shorter than 100 years are used. Selection of a time horizon affects decisions on financial mechanisms and carbon credit. Simple adaptations can allow a time horizon to be specified and used to calculate mitigation benefits and at the same time reserve a given percentage of weight in decision making for generations beyond the end of the time horizon. The choice of a time horizon will heavily influence whether mitigation options such as avoided deforestation are considered viable.

The approach taken in the present investigation was to examine reactions to positive and negative employer information by eliciting online (i.e., moment-tomoment) reactions in a simulated computer-based job fair. Reactions to positive and negative information commonly reveal a negatively biased asymmetry. Positively biased asymmetries have been documented in the psychological literature, but they are rare. This article shows evidence for such asymmetry in reactions to realistic information in this simulated recruitment context. The intensity of reactions to positive information was greater than the intensity of reactions to negative information on the same attribute. Findings are discussed in relation to research on temporal discounting in vocational preference.

Impatience for reward is a facet of many psychiatric disorders. We draw attention to a growing literature finding greater discounting of delayed reward, an important aspect of impatience, across a range of psychiatric disorders. We propose these findings are best understood by considering the goals and motivation for discounting future reward. We characterize these as arising from either the opportunity costs of waiting or the uncertainty associated with delayed reward. We link specific instances of higher discounting in psychiatric disorder to heightened subjective estimates of either of these factors. We propose these costs are learned and represented based either on a flexible cognitive model of the world, an accumulation of previous experience, or through evolutionary specification. Any of these can be considered suboptimal for the individual if the resulting behavior results in impairments in personal and social functioning and/or in distress. By considering the neurochemical and neuroanatomical implementation of these processes, we illustrate how this approach can in principle unite social, psychological and biological conceptions of impulsive choice.

We review behavioral-and neuroeconomic research that identifies temporal discounting as an important component in the development and maintenance of drug addiction. First we review behavioral economic research that explains and documents the contribution of temporal discounting to addiction. This is followed with recent insights from neuroeconomics that may provide an explanation of why drug dependent individuals discount the future. Specifically, neuroeconomics has identified two competing neural systems that are related to temporal discounting using brainimaging techniques that examine the relative activation of different brain regions for temporal discounting. According to the competing neural systems account, choices for delayed outcomes are related to the prefrontal cortex (i.e., the "executive system") and choices for immediate outcomes are related to the limbic brain regions (i.e., the "impulsive system"). Temporal discounting provides a useful framework for future imaging research, and suggests a novel approach to designing effective drug dependence prevention and treatment programs.

As social animals, we regularly act in the interest of others by making decisions on their behalf. These decisions can take the form of choices between smaller short-term rewards and larger long-term rewards, and can be effectively indexed by temporal discounting (TD). In a TD paradigm, a reward loses subjective value with increasing delay presumably because it becomes more difficult to simulate how much the recipient (e.g., future self) will value it. If this is the case, then the value of delayed rewards should be discounted even more steeply when we are choosing for someone whose feelings we do not readily simulate, such as socially distant strangers. Second, the ability to simulate shows individual differences and is indexed by trait empathy. We hypothesized that individuals high in trait empathy will more readily simulate, and hence discount less steeply for distant others, compared to those who are low on trait empathy. To test these predictions, we asked 63 participants from the general population to perform a TD task from the perspectives of close and distant others, as well as their own. People were found to discount less steeply for themselves, and the steepness of TD increased with increasing distance from self. Additionally, individuals who scored high in trait empathy were found to discount less steeply for distant others compared to those who scored low. These findings confirm the role of empathy in determining how we choose rewards for others.

Drawing on the psychological principle that proximal consequences influence behavior more strongly than distal consequences, the authors tested the hypothesis that criminal suspects exhibit a short-sightedness during police interrogation that increases their risk for confession. Consistent with this hypothesis, Experiment 1 showed that participants (N = 81) altered how frequently they admitted to criminal and unethical behaviors during an interview to avoid a proximal consequence even though doing so increased their risk of incurring a distal consequence. Experiment 2 (N = 143) yielded the same pattern, but with a procedure that reversed the order of the proximal and distal consequences, thereby ruling out the possibility that it was the unique characteristics of the consequences rather than their proximity that influenced the admission rate. The authors discuss the supported psychological process as a potential explanation for several well-established findings reported in the literature on confessions.

Decision making often involves choosing between small, short-term rewards and large, long-term rewards. All animals, humans included, discount future rewards—the present value of delayed rewards is viewed as less than the value of immediate rewards. Despite its ubiquity, there exists considerable but unexplained variation between species in their capacity to wait for rewards—that is, to exert patience or self-control. Using two closely related primates—common marmosets (Callithrix jacchus) and cotton-top tamarins (Saguinus oedipus)—we uncover a variable that may explain differences in how species discount future rewards. Both species faced a self-control paradigm in which individuals chose between taking an immediate small reward and waiting a variable amount of time for a large reward. Under these conditions, marmosets waited significantly longer for food than tamarins. This difference cannot be explained by life history, social behaviour or brain size. It can, however, be explained by feeding ecology: marmosets rely on gum, a food product acquired by waiting for exudate to flow from trees, whereas tamarins feed on insects, a food product requiring impulsive action. Foraging ecology, therefore, may provide a selective pressure for the evolution of self-control.

Clinic-referred teens (ages 12-19) with ADHD and ODD (N = 101) were compared to community control (CC) teens, equated for age and sex, (N = 39) on a variety of psychological tasks assessing executive functioning (EF), temporal reward discounting, and time estimation and reproduction. A factor analysis reduced the EF measures to three dimensions, representing CPF Inattention, Working Memory, and CPT Inhibition. Results indicated that the ADHD group had significantly more CPT Inattention than the CC group. No differences were found for Working Memory or CPT Inhibition. The ADHD group displayed significantly greater temporal discounting of delayed hypothetical monetary rewards relative to immediate ones and manifested more impaired time reproduction, but not time estimation, than did the CC group. Main effects for level of IQ were found only on the Working Memory factor and largely did not interact with the group factor otherwise. The group differences in CPT Inattention, temporal disc...

People tend to attach less value to a good if they know a delay will occur before they obtain it. For example, people value receiving $100 tomorrow more than receiving $100 in 10 years. We explored one reason for this tendency (due to Parfit, 1984): In terms of psychological properties, such as beliefs, values, and goals, the decision maker is more closely linked to the person (his or her future self) receiving $100 tomorrow than to the person receiving $100 in 10 years. For this reason, he or she prefers his or her nearer self to have the $100 rather than his or her more remote self. Studies 1 and 2 showed that the greater the rated psychological connection between 2 parts of a participant’s life, the less he or she discounted future monetary and nonmonetary benefits (e.g., good days at work) over that interval. In Studies 3–5, participants read about characters who undergo large life-changing (and connectedness-weakening) events at different points in their lives and then made decisions about the timing of benefits on behalf of these characters. All 5 studies revealed a relation between perceived psychological connectedness and intertemporal choice: Participants preferred benefits to occur before large changes in connectedness but preferred costs to occur after these changes.

Discounting tasks were used to evaluate whether gambling and non-gambling college students (categorized based on their scores on the South Oaks Gambling Screen) differed in the degree to which they discounted delayed and probabilistic rewards. Hyperbola-like functions provided equally good descriptions of discounting in both groups. Both groups discounted large delayed amounts less steeply than small delayed amounts, whereas both groups discounted large probabilistic amounts more steeply than small probabilistic amounts. Gamblers discounted probabilistic rewards less steeply than non-gamblers, suggesting that gamblers are impulsive in the sense that they are less affected by risk than non-gamblers. However, gamblers did not discount delayed rewards more steeply than non-gamblers. The results argue against the view that impulsivity is a general trait that includes both an inability to delay gratification and a tendency to take risks.

Two algorithms are commonly applied in computerized temporal discounting procedures (Decreasing Adjustment and Double-Limit Algorithms); however, the degree to which the two algorithms produce similar patterns of discounting is unknown. The present experiment compared the two common algorithms across sign (gains and losses) and magnitude ($10 and $1000) conditions. Twenty participants made choices between larger later and smaller sooner alternatives that were presented by each of the algorithms in separate conditions. Strong correlations were found between the two measures; however, the Decreasing Adjustment Algorithm tended to produce lower indifference points and higher rates of discounting than the Double-Limit Algorithm. Both algorithms found significant magnitude effects. Less consistent results were found when comparing the two algorithms across sign. The present results suggest that researchers should apply caution when making comparisons between outcomes of delay discounting studies that have used the two different algorithms. However, the interpretation of findings from individual studies is probably not strongly affected by the use of different computer algorithms.

In temporal discounting, individuals often prefer smaller immediate rewards to larger delayed rewards, implying a trade off between the magnitude and delay of future rewards. While recent functional magnetic resonance imaging (fMRI) investigations of temporal discounting have generated conflicting findings, no studies have focused on whether distinct neural substrates respond to the magnitude and delay of future rewards. Combining a novel, temporally distributed discounting task with event-related fMRI, we found that while nucleus accumbens (NAcc), mesial prefrontal cortical (MPFC), and posterior cingulate cortical (PCC) activation positively correlated with future reward magnitude, dorsolateral prefrontal cortical (DLPFC) and posterior parietal cortical (PPC) activation negatively correlated with future reward delay. Further, more impulsive individuals showed diminished NAcc activation to the magnitude of future rewards and greater deactivations to delays of future rewards in the MPFC, DLPFC, and PPC. These findings suggest that while mesolimbic dopamine projection regions show greater sensitivity to the magnitude of future rewards, lateral cortical regions show greater (negative) sensitivity to the delay of future rewards, potentially reconciling different neural accounts of temporal discounting.

In 3 studies, participants made choices between hypothetical financial, environmental, and health gains and losses that took effect either immediately or with a delay of 1 or 10 years. In all 3 domains, choices indicated that gains were discounted more than losses. There were no significant differences in the discounting of monetary and environmental outcomes, but health gains were discounted more and health losses were discounted less than gains or losses in the other 2 domains. Correlations between implicit discount rates for these different choices suggest that discount rates are influenced more by the valence of outcomes (gains vs. losses) than by domain (money, environment, or health). Overall, results indicate that when controlling as many factors as possible, at short to medium delays, environmental outcomes are discounted in a similar way to financial outcomes, which is good news for researchers and policy makers alike.

Numerous studies show that individuals with substance use and gambling problems discount delayed and probabilistic outcomes at different rates than controls. Few studies, however, have investigated the association of discounting with antisocial personality disorders (ASPD), and none have evaluated whether sex impacts these relationships. Because females with ASPD exhibit different patterns of antisocial behavior than their male counterparts, they may also differ in their decision-making tendencies. This study examined the effects of ASPD and sex on discounting in pathological gamblers. Results revealed effects of ASPD, and an interaction between ASPD and sex, on probability discounting rates. None of these variables, however, were related to delay discounting. Females with ASPD highly preferred probabilistic outcomes, suggesting that female gamblers with ASPD are particularly impulsive when it comes to probabilistic rewards. Greater understanding of sex differences in ASPD might help guide the selection of more effective sex-specific prevention and treatment programs.

To make adaptive choices, individuals must sometimes exhibit patience, forgoing immediate benefits to acquire more valuable future rewards [1,2,3]. Although humans account for future consequences when making temporal decisions [4], many animal species wait only a few seconds for delayed benefits [5,6,7,8,9,10]. Current research thus suggests a phylogenetic gap between patient humans and impulsive, present-oriented animals [9,11], a distinction with implications for our understanding of economic decision making [12] and the origins of human cooperation [13]. On the basis of a series of experimental results, we reject this conclusion. First, bonobos (Pan paniscus) and chimpanzees (Pan troglodytes) exhibit a degree of patience not seen in other animals tested thus far. Second, humans are less willing to wait for food rewards than are chimpanzees. Third, humans are more willing to wait for monetary rewards than for food, and show the highest degree of patience only in response to decisions about money involving low opportunity costs. These findings suggest that core components of the capacity for future-oriented decisions evolved before the human lineage diverged from apes. Moreover, the different levels of patience that humans exhibit might be driven by fundamental differences in the mechanisms representing biological versus abstract rewards.