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Discounting
Kinds of Discounting Terms modified by Discounting Selected AbstractsOPTIMAL DISCOUNTING IN CONTROL PROBLEMS THAT SPAN MULTIPLE GENERATIONSNATURAL RESOURCE MODELING, Issue 3 2005FRANK CALIENDO ABSTRACT. The principal contribution of this paper is the linking together of separate control problems across multiple generations using the bequest motive, intergenerational altruism, rational expectations, and solution boundary conditions. We demonstrate that discounting at the market rate of interest is an endogenous characteristic of a general equilibrium, optimal control problem that spans multiple generations. Within the confines of our model, we prove that it is optimal to discount at the market rate of interest the social benefits to distant generations from immediate clean up at toxic waste sites if the current generation that bears the cleanup cost is perfectly altruistic towards future generations. Also, we show that this result holds for alternative assumptions regarding pure time preference. Moreover, the result holds regardless of whether selfish interim generations attempt to undo the provisions made for distant generations. In our distortion-free deterministic model, the evidence for intergenerational discounting at the market rate of interest is compelling. [source] Impulsivity: The Behavioural and Neurological Science of DiscountingDRUG AND ALCOHOL REVIEW, Issue 5 2010Daniel J. Upton No abstract is available for this article. [source] Discounting and the role of the relation between causesEUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 2 2005Frank Van Overwalle This research investigates how the relation between two causes (i.e. whether they co-occur or not) affects the likelihood to discount one of them. In two experiments, two causes were either systematically paired together (positive relation), were paired with many other causes (independent relation), or were never paired together (negative relation). The results indicate that discounting of one of the causes (target cause) depends on the relation with the other cause (alternative cause) and the order in which the alternative cause was presented and produced the outcome alone. If information on the independent outcome of the alternative cause came prior to the joint outcome of the alternative and target cause (forward order), then discounting of the target cause occurred regardless of the relation between the two causes. If, however, information on the independent outcome of the alternative cause came after the joint outcome of the alternative and target cause (backward order), then discounting of the target cause occurred mainly when there was a positive or negative relation between the causes, but not when there was an independent relation. The degree of backward discounting given a positive or negative relation was largely identical. These results are consistent with the retrospective revaluation hypothesis of Dickinson and Burke (1996) and shed new light on the role of the relation between causes on discounting. Copyright © 2004 John Wiley & Sons, Ltd. [source] Discounting and the Treatment of Taxes in Impairment ReviewsJOURNAL OF BUSINESS FINANCE & ACCOUNTING, Issue 5-6 2007Erlend Kvaal Abstract:,IAS 36 requires an asset's recoverable amount to be measured by discounting its pre-tax rather than post-tax cash flows. Although defined so as to produce the same value, the pre-tax approach is claimed to be simpler and more reliable. The paper demonstrates that an appropriate pre-tax discount rate varies between assets with different tax depreciation schedules and that it changes over time. Hence, pre-tax discounting is likely to become complex. The paper advocates an amendment of the standard such that value in use is measured by company-specific after-tax cash flows, and such that deferred taxes are included in the impairment review. [source] An Introduction to Spatial DiscountingJOURNAL OF REGIONAL SCIENCE, Issue 1 2001Charles Perrings Research on the valuation of environmental externalities shows that decision makers tend to discount not only over time but across space. Just as time discounting has implications for intergenerational equity, geographical or spatial discounting has implications for intragenerational equity. Similarly, just as positive time discount rates are warranted by positive net rates of growth of the capital stock, positive spatial discount rates may be warranted by the fact that enviironmental (or other external effects of economic activity are diffused at positive rates. This paper introduces the notion of spatial discounting and explores its welfare implications through a simple diffusion model. [source] Judgmental Discounting and Environmental Risk Perception: Dimensional Similarities, Domain Differences, and Implications for SustainabilityJOURNAL OF SOCIAL ISSUES, Issue 1 2007Alexander Gattig Environmental risks constitute a special category of risks because they often involve consequences that are highly uncertain, strongly delayed, occurring at distant places, and,therefore,mostly borne by others. Economic, decision,theoretic, and psychological research about the way people deal with such consequences is reviewed. Two major findings are presented: first, there is evidence that discounting mechanisms are stable across different preference dimensions (uncertainty, temporal, spatial, and social distance). Second, discount rates tend to vary across different problem domains (e.g., environmental vs. health vs. financial risks). In particular, it appears that temporal discounting is less pronounced for environmental risks than in other domains. Several factors are identified that affect the nature of the risk evaluation process, and it is argued that environmental risks differ from other risks on such factors. These environmental-risk characteristics may have important implications for policy strategies to promote environmental sustainability. Contrary to other domains, appealing to the public's long-term preferences may be successful. Also in policy making, insights from standard economic decision theory to environmental decision making should be applied with caution. [source] The Effect of Discounting on Policy Choices in Inflation Targeting Regimes,THE ECONOMIC JOURNAL, Issue 508 2006SGB Henry This article assesses the implications of discounting on a result derived by Bean (1998): that in a model of monetary policy where policy acts with a lag, the outcomes of monetary policy are very similar for a wide range of preferences of the monetary authority with respect to inflation and output stability. We show that when the authority discounts the future, outcomes become more sensitive to its preferences, and that it is important to take the discount rate into account when examining the question of how the authority's remit should be specified. [source] Stable Optimal Cycles With Small Discounting in a Two-sector Discrete-time Model: A Non-bifurcation ApproachTHE JAPANESE ECONOMIC REVIEW, Issue 3 2001Harutaka TakahashiArticle first published online: 18 DEC 200 This paper presents a standard two-sector optimal growth model with general neoclassical production functions: strictly quasi-concave, twice continuously differentiable homogeneous of degree 1 functions. Instead of applying the standard local bifurcation theory, I exploit two well established properties in Turnpike Theory,"simple dynamics" and the Neighbourhood Turnpike, and, combining both results, I demonstrate that there exists an interval of the discount factor near 1 such that a corresponding optimal steady state is totally unstable and an optimal path converges asymptotically to a two-period cycle for a chosen discount factor in it. JEL Classification Numbers: O21, O41. [source] A General Formula for Valuing Defaultable SecuritiesECONOMETRICA, Issue 5 2004P. Collin-Dufresne Previous research has shown that under a suitable no-jump condition, the price of a defaultable security is equal to its risk-neutral expected discounted cash flows if a modified discount rate is introduced to account for the possibility of default. Below, we generalize this result by demonstrating that one can always value defaultable claims using expected risk-adjusted discounting provided that the expectation is taken under a slightly modified probability measure. This new probability measure puts zero probability on paths where default occurs prior to the maturity, and is thus only absolutely continuous with respect to the risk-neutral probability measure. After establishing the general result and discussing its relation with the existing literature, we investigate several examples for which the no-jump condition fails. Each example illustrates the power of our general formula by providing simple analytic solutions for the prices of defaultable securities. [source] CENTRAL BANKS: FROM POLITICALLY INDEPENDENT TO MARKET-DEPENDENT INSTITUTIONSECONOMIC AFFAIRS, Issue 3 2009Pedro Schwartz Responses to the financial crisis are undermining the Chinese walls painfully built between monetary and fiscal authorities. Central banks and state treasuries are working side by side as lenders of last resort. Central banks are helping economic ministers with purchases of public debt and discounting of private paper. Regulation and control of financial institutions is now a political football. Central banks must be seen again as market-dependent institutions in a world of currency competition. Privatisation in law or in fact is back on the table. [source] REVIEW: Impulsivity as a determinant and consequence of drug use: a review of underlying processesADDICTION BIOLOGY, Issue 1 2009Harriet De Wit ABSTRACT Impulsive behaviors are closely linked to drug use and abuse, both as contributors to use and as consequences of use. Trait impulsivity is an important determinant of drug use during development, and in adults momentary ,state' increases in impulsive behavior may increase the likelihood of drug use, especially in individuals attempting to abstain. Conversely, acute and chronic effects of drug use may increase impulsive behaviors, which may in turn facilitate further drug use. However, these effects depend on the behavioral measure used to assess impulsivity. This article reviews data from controlled studies investigating different measures of impulsive behaviors, including delay discounting, behavioral inhibition and a newly proposed measure of inattention. Our findings support the hypothesis that drugs of abuse alter performance across independent behavioral measures of impulsivity. The findings lay the groundwork for studying the cognitive and neurobiological substrates of impulsivity, and for future studies on the role of impulsive behavior as both facilitator and a result of drug use. [source] Subjective neuronal coding of reward: temporal value discounting and riskEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2010Wolfram Schultz Abstract A key question in the neurobiology of reward relates to the nature of coding. Rewards are objects that are advantageous or necessary for the survival of individuals in a variety of environmental situations. Thus reward appears to depend on the individual and its environment. The question arises whether neuronal systems in humans and monkeys code reward in subjective terms, objective terms or both. The present review addresses this issue by dealing with two important reward processes, namely the individual discounting of reward value across temporal delays, and the processing of information about risky rewards that depends on individual risk attitudes. The subjective value of rewards decreases with the temporal distance to the reward. In experiments using neurophysiology and brain imaging, dopamine neurons and striatal systems discount reward value across temporal delays of a few seconds, despite unchanged objective reward value, suggesting subjective value coding. The subjective values of risky outcomes depend on the risk attitude of individual decision makers; these values decrease for risk-avoiders and increase for risk-seekers. The signal for risk and the signal for the value of risky reward covary with individual risk attitudes in regions of the human prefrontal cortex, suggesting subjective rather than objective coding of risk and risky value. These data demonstrate that important parameters of reward are coded in a subjective manner in key reward structures of the brain. However, these data do not rule out that other neurons or brain structures may code reward according to its objective value and risk. [source] Discounting and the role of the relation between causesEUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 2 2005Frank Van Overwalle This research investigates how the relation between two causes (i.e. whether they co-occur or not) affects the likelihood to discount one of them. In two experiments, two causes were either systematically paired together (positive relation), were paired with many other causes (independent relation), or were never paired together (negative relation). The results indicate that discounting of one of the causes (target cause) depends on the relation with the other cause (alternative cause) and the order in which the alternative cause was presented and produced the outcome alone. If information on the independent outcome of the alternative cause came prior to the joint outcome of the alternative and target cause (forward order), then discounting of the target cause occurred regardless of the relation between the two causes. If, however, information on the independent outcome of the alternative cause came after the joint outcome of the alternative and target cause (backward order), then discounting of the target cause occurred mainly when there was a positive or negative relation between the causes, but not when there was an independent relation. The degree of backward discounting given a positive or negative relation was largely identical. These results are consistent with the retrospective revaluation hypothesis of Dickinson and Burke (1996) and shed new light on the role of the relation between causes on discounting. Copyright © 2004 John Wiley & Sons, Ltd. [source] Rats bred for high alcohol drinking are more sensitive to delayed and probabilistic outcomesGENES, BRAIN AND BEHAVIOR, Issue 7 2008C. J. Wilhelm Alcoholics and heavy drinkers score higher on measures of impulsivity than nonalcoholics and light drinkers. This may be because of factors that predate drug exposure (e.g. genetics). This study examined the role of genetics by comparing impulsivity measures in ethanol-naive rats selectively bred based on their high [high alcohol drinking (HAD)] or low [low alcohol drinking (LAD)] consumption of ethanol. Replicates 1 and 2 of the HAD and LAD rats, developed by the University of Indiana Alcohol Research Center, completed two different discounting tasks. Delay discounting examines sensitivity to rewards that are delayed in time and is commonly used to assess ,choice' impulsivity. Probability discounting examines sensitivity to the uncertain delivery of rewards and has been used to assess risk taking and risk assessment. High alcohol drinking rats discounted delayed and probabilistic rewards more steeply than LAD rats. Discount rates associated with probabilistic and delayed rewards were weakly correlated, while bias was strongly correlated with discount rate in both delay and probability discounting. The results suggest that selective breeding for high alcohol consumption selects for animals that are more sensitive to delayed and probabilistic outcomes. Sensitivity to delayed or probabilistic outcomes may be predictive of future drinking in genetically predisposed individuals. [source] On the Interaction of Risk and Time Preferences: An Experimental StudyGERMAN ECONOMIC REVIEW, Issue 3 2001Vital Anderhub Experimental studies of risk and time preference typically focus on one of the two phenomena. The goal of this paper is to investigate the (possible) correlation between subjects' attitude to risk and their time preference. For this sake we ask 61 subjects to price a simple lottery in three different scenarios. At the first, the lottery premium is paid ,now'. At the second, it is paid ,later'. At the third, it is paid ,even later,. By comparing the certainty equivalents offered by the subjects for the three lotteries, we test how time and risk preferences are interrelated. Since the time interval between ,now' and ,later' is the same as between ,later' and ,even later', we also test the hypothesis of hyperbolic discounting. The main result is a statistically significant negative correlation between subjects' degrees of risk aversion and their (implicit) discount factors. Moreover, we show that the negative correlation is independent of the method used to elicit certainty equivalents (willingness to pay versus willingness to accept). [source] Technology and Cartel Stability under Vertical DifferentiationGERMAN ECONOMIC REVIEW, Issue 4 2000Luca Lambertini The interplay between R&D activity and cartel stability is investigated in a vertical differentiation framework with convex costs. The behaviour of firms' critical discount factors as the curvature of the cost function varies is investigated, considering either price- or quantity-setting behaviour. In order to stabilize collusion, firms are better off playing à la Cournot and supplying the non-cooperative qualities. There emerges a tradeoff between the reduction of the convexity of the cost function and the associated increase in marginal cost. The decision to carry out joint or independent ventures in research is also investigated, showing that such a decision is non-monotone in intertemporal discounting. Policy measures are then briefly discussed. [source] Frontoparietal cortical activity of methamphetamine-dependent and comparison subjects performing a delay discounting taskHUMAN BRAIN MAPPING, Issue 5 2007John R. Monterosso Abstract Relative to individuals who do not have addictive disorders, drug abusers exhibit greater devaluation of rewards as a function of their delay ("delay discounting"). The present study sought to extend this finding to methamphetamine (MA) abusers and to help understand its neural basis. MA abusers (n = 12) and control subjects who did not use illicit drugs (n = 17) participated in tests of delay discounting with hypothetical money rewards. We then used a derived estimate of each individual's delay discounting to generate a functional magnetic resonance imaging probe task consisting of three conditions: "hard choices," requiring selections between "smaller, sooner" and "larger, later" alternatives that were similarly valued given the individual's delay discounting; "easy choices," in which alternatives differed dramatically in value; and a "no choice" control condition. MA abusers exhibited more delay discounting than control subjects (P < 0.05). Across groups, the "hard choice > no choice" contrast revealed significant effects in the ventrolateral prefrontal cortex, dorsolateral prefrontal cortex (DLPFC), dorsal anterior cingulate cortex, and areas surrounding the intraparietal sulcus (IPS). With group comparisons limited to these clusters, the "hard choice > easy choice" contrast indicated significant group differences in task-related activity within the left DLPFC and right IPS; qualitatively similar nonsignificant effects were present in the other clusters tested. Whereas control subjects showed less recruitment associated with easy than with hard choices, MA abusers generally did not. Correlational analysis did not indicate a relationship between this anomaly in frontoparietal recruitment and greater degree of delay discounting exhibited by MA abusers. Therefore, while apparent inefficiency of cortical processing related to decision-making in MA abusers may contribute to the neural basis of enhanced delay discounting by this population, other factors remain to be identified. Hum. Brain Mapp, 2007. © 2006 Wiley-Liss, Inc. [source] Studying the relation between temporal reward discounting tasks used in populations with ADHD: A factor analysisINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 3 2010Anouk Scheres Abstract Background: This study aimed at investigating the relationship between tasks that have been used in attention deficit hyperactivity disorder (ADHD) to measure choices between smaller immediate and larger delayed rewards: real and hypothetical temporal discounting tasks, and single-choice paradigms. Methods: Participants were 55 undergraduate psychology students. Tasks included a real and hypothetical version of a temporal discounting (TD) task with choices between a large reward (10 cents) after delays up to 60 seconds, and smaller immediate rewards (2,8 cents); two versions of a hypothetical temporal discounting task with choices between a large reward ($100) after delays up to 120 months, and smaller immediate rewards ($1,$95); a Choice Delay Task with choices between one point now and two points after 30 seconds (one point is worth five cents). Results: Correlation analyses showed that the real and the hypothetical TD tasks with 10 cents were very strongly associated. However, the hypothetical TD tasks with $100 did not correlate with either the real or the hypothetical TD task with 10 cents. Principal component analysis extracted two components: one for small amounts and short delays, and a second one for large rewards and long delays. Conclusions: Temporal reward discounting is not a uniform construct. Functional brain imaging research could shed more light on unique brain activation patterns associated with different forms of temporal reward discounting. Copyright © 2010 John Wiley & Sons, Ltd. [source] Social discounting and delay discountingJOURNAL OF BEHAVIORAL DECISION MAKING, Issue 1 2008Howard Rachlin Abstract Social discounting was measured as the amount of money a participant was willing to forgo to give a fixed amount (usually $75) to another person. In the first experiment, amount forgone was a hyperbolic function of the social distance between the giver and receiver. In the second experiment, degree of social discounting was an increasing function of reward magnitude whereas degree of delay discounting was a decreasing function of reward magnitude. In the third experiment, the shape of the function relating delayed rewards to equally valued immediate rewards for another person was predicted from individual delay and social discount functions. All in all, the studies show that the social discount function, like delay and probability discount functions, is hyperbolic in form. Copyright © 2007 John Wiley & Sons, Ltd. [source] De-escalation after repeated negative feedback: emergent expectations of failureJOURNAL OF BEHAVIORAL DECISION MAKING, Issue 5 2004Brian J. Zikmund-FisherArticle first published online: 26 NOV 200 Abstract Research on willingness to make marginal investments (e.g., the escalation and sunk cost literatures) has often focused on project completion decisions, such as the "radar-blank plane." This paper discusses a fundamentally different type of marginal investment decision, that of couples deciding whether to continue infertility treatment in the face of repeated failures. Two experiments based on this context show that when people face multiple independent chances to achieve a valued goal but are unsure about chances of success, premature quitting or "de-escalation" is the norm. Repeated negative feedback appears to induce individuals to see each successive failure as more and more diagnostic. As a result, even a short series of failed attempts evokes beliefs that future attempts will also fail. These emergent expectations of failure, generated by causal attribution processes, associative learning, and/or discounting of ambiguous information, appear very compelling and induce people to forgo profitable marginal investments. Copyright © 2004 John Wiley & Sons, Ltd. [source] Discounting and the Treatment of Taxes in Impairment ReviewsJOURNAL OF BUSINESS FINANCE & ACCOUNTING, Issue 5-6 2007Erlend Kvaal Abstract:,IAS 36 requires an asset's recoverable amount to be measured by discounting its pre-tax rather than post-tax cash flows. Although defined so as to produce the same value, the pre-tax approach is claimed to be simpler and more reliable. The paper demonstrates that an appropriate pre-tax discount rate varies between assets with different tax depreciation schedules and that it changes over time. Hence, pre-tax discounting is likely to become complex. The paper advocates an amendment of the standard such that value in use is measured by company-specific after-tax cash flows, and such that deferred taxes are included in the impairment review. [source] Cost Comparison of Catheter Ablation and Medical Therapy in Atrial FibrillationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2007F.R.C.P.C., YAARIV KHAYKIN M.D. Introduction: There is emerging evidence for clinical superiority of catheter ablation over rate and rhythm control strategies in paroxysmal atrial fibrillation (PAF). The objective of this study was to compare costs related to medical therapy versus catheter ablation for PAF in Ontario (Canada). Methods: Costs related to medical therapy in the analysis included the cost of anticoagulation, rate and rhythm control medications, noninvasive testing, physician follow-up visits, and hospital admissions, as well as the cost of complications related to this management strategy. Costs related to catheter ablation were assumed to include the cost of the ablation tools (electroanatomic mapping or intracardiac echocardiography-guided pulmonary vein ablation), hospital and physician billings, and costs related to periprocedural medical care and complications. Costs related to these various elements were obtained from the Canadian Registry of Atrial Fibrillation (CARAF), government fee schedules, and published data. Sensitivity analyses looking at a range of initial success rates (50,75%) and late attrition rates (1,5%), prevalence of congestive heart failure (CHF) (20,60%), as well as discounting varying from 3% to 5% per year were performed. Results: The cost of catheter ablation ranged from $16,278 to $21,294, with an annual cost of $1,597 to $2,132. The annual cost of medical therapy ranged from $4,176 to $5,060. Costs of ongoing medical therapy and catheter ablation for PAF equalized at 3.2,8.4 years of follow-up. Conclusion: Catheter ablation is a fiscally sensible alternative to medical therapy in PAF with cost equivalence after 4 years. [source] THE DEMAND FOR BEER, WINE AND SPIRITS: A SURVEY OF THE LITERATUREJOURNAL OF ECONOMIC SURVEYS, Issue 3 2010James Fogarty Abstract The demand for alcohol literature is vast and much conflicting information about the nature of the demand for alcoholic beverages has been published. This paper presents a survey of the literature, and then uses the technique of meta-regression analysis to establish insights into the nature of the demand for beer, wine and spirits. Unlike previous meta-studies of the demand for alcoholic beverages this study adjusts for the precision of each elasticity estimate. The analysis presented suggests reported elasticity estimates will be influenced by such factors as estimation technique, data frequency and time period under consideration. With respect to time, the findings suggest that the demand for alcoholic beverages has become less inelastic since the mid-1950s and that the income elasticity has been falling since the mid-1960s. The analysis also found support for the idea that alcohol as a commodity group is a necessity, and that consumers respond to price discounting with inventory behaviour rather than true substitution behaviour. Little support is found for the idea that the demand for alcoholic beverages varies fundamentally across most countries, although wine may be an exception. [source] Models of Quality-Adjusted Life Years when Health Varies Over Time: Survey and AnalysisJOURNAL OF ECONOMIC SURVEYS, Issue 2 2006Kristian Schultz Hansen Abstract., Quality-adjusted life year (QALY) models are widely used for economic evaluation in the health care sector. In the first part of the paper, we establish an overview of QALY models where health varies over time and provide a theoretical analysis of model identification and parameter estimation from time trade-off (TTO) and standard gamble (SG) scores. We investigate deterministic and probabilistic models and consider five different families of discounting functions in all. The second part of the paper discusses four issues recurrently debated in the literature. This discussion includes questioning the SG method as the gold standard for estimation of the health state index, re-examining the role of the constant-proportional trade-off condition, revisiting the problem of double discounting of QALYs, and suggesting that it is not a matter of choosing between TTO and SG procedures as the combination of these two can be used to disentangle risk aversion from discounting. We find that caution must be taken when drawing conclusions from models with chronic health states to situations where health varies over time. One notable difference is that in the former case, risk aversion may be indistinguishable from discounting. [source] The evolution of self-fertilization and inbreeding depression under pollen discounting and pollen limitationJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 3 2005E. PORCHER Abstract We model the evolution of plant mating systems under the joint effects of pollen discounting and pollen limitation, using a dynamic model of inbreeding depression, allowing for partial purging of recessive lethal mutations by selfing. Stable mixed mating systems occur for a wide range of parameter values with pollen discounting alone. However, when typical levels of pollen limitation are combined with pollen discounting, stable selfing rates are always high but less than 1 (0.9 < s < 1 in most cases); in this situation, complete selfing does not evolve because pollen discounting becomes very large at high selfing rates, so that the automatic advantage of selfing changes to a disadvantage. These results suggest that mixed mating systems with high selfing rates can be maintained by selection, whereas mixed mating systems with low to moderate selfing rates are more likely attributable to unavoidable geitonogamous selfing. [source] Shaping Self-Concept: The Elusive Importance EffectJOURNAL OF PERSONALITY, Issue 2 2006Lew Hardy ABSTRACT This study examined the hypothesis that the contributions of specific domains of self-concept to global self-concept are dependent upon their perceived importance. The Self Description Questionnaire III was administered to a sample of 506 male and female participants. Analysis of the data using Marsh's original individually weighted multiple regression model confirmed previous findings of no support for the importance hypothesis. In contrast, the results from alternative individually weighted regression models provided strong support for the importance hypothesis. These alternative models utilized idiographically determined as opposed to nomothetically determined relative importance. The data also showed evidence of strong discounting for certain domains, moderate discounting for other domains, and no discounting for still others. The findings challenge previous thinking on the limited role of the importance hypothesis. [source] Pharmacologic Dissociation Between Impulsivity and Alcohol Drinking in High Alcohol Preferring MiceALCOHOLISM, Issue 8 2010Brandon G. Oberlin Background:, Impulsivity is genetically correlated with, and precedes, addictive behaviors and alcoholism. If impulsivity or attention is causally related to addiction, certain pharmacological manipulations of impulsivity and/or attention may affect alcohol drinking, and vice versa. The current studies were designed to explore the relationship among impulsivity, drinking, and vigilance in selectively bred High Alcohol Preferring (HAP) mice, a line that has previously demonstrated both high impulsivity and high alcohol consumption. Amphetamine, naltrexone, and memantine were tested in a delay discounting (DD) task for their effects on impulsivity and vigilance. The same drugs and doses were also assessed for effects on alcohol drinking in a 2-bottle choice test. Methods:, HAP mice were subjected to a modified version of adjusting amount DD using 0.5-second and 10-second delays to detect decreases and increases, respectively, in impulsive responding. In 2 experiments, mice were given amphetamine (0.4, 0.8, or 1.2 mg/kg), naltrexone (3 and 10 mg/kg), and memantine (1 and 5 mg/kg) before DD testing. Another pair of studies used scheduled access, 2-bottle choice drinking to assess effects of amphetamine (0.4, 1.2, or 3.0 mg/kg), naltrexone (3 and 10 mg/kg), and memantine (1 and 5 mg/kg) on alcohol consumption. Results:, Amphetamine dose-dependently reduced impulsivity and vigilance decrement in DD, but similar doses left alcohol drinking unaffected. Naltrexone and memantine decreased alcohol intake at doses that did not affect water drinking but had no effects on impulsivity or vigilance decrement in the DD task. Conclusions:, Contrary to our hypothesis, none of the drugs tested here, while effective on either alcohol drinking or impulsivity, decreased both behaviors. These findings suggest that the genetic association between drinking and impulsivity observed in this population is mediated by mechanisms other than those targeted by the drugs tested in these studies. [source] High-Alcohol Preferring Mice Are More Impulsive Than Low-Alcohol Preferring Mice as Measured in the Delay Discounting TaskALCOHOLISM, Issue 7 2009B. G. Oberlin Background:, Repeated studies have shown that high impulsivity, when defined as the tendency to choose small immediate rewards over larger delayed rewards, is more prevalent in drug addicts and alcoholics when compared with nonaddicts. Assessing whether impulsivity precedes and potentially causes addiction disorders is difficult in humans because they all share a history of drug use. In this study, we address this question by testing alcohol-naïve mice from lines showing heritable differences in alcohol intake. Methods:, Replicated selected lines of outbred high-alcohol preferring (HAP) mice were compared to a low-alcohol preferring (LAP) line as well as the low-drinking progenitor line (HS/Ibg) on an adjusting amount delay discounting (DD) task. The DD task employs 2 levers to present subjects with a choice between a small, immediate and a large, delayed saccharin reward. By adjusting the quantity of the immediate reward up and down based on choice behavior, the task allows an estimate of how the subjective value of the delayed reinforcer decreases as delays increase. Latency to respond was also measured for each trial. Results:, Both HAP2 and HAP1 lines of mice were more impulsive than the LAP2 and HS/Ibg lines, respectively. Hyperbolic curve-fitting confirmed steeper discounting in the high-alcohol drinking lines. In addition, the high-alcohol drinking lines demonstrated greater within-session increases in reaction times relative to the low-alcohol drinking lines. No other differences (consumption of saccharin, total trials completed) consistently mapped onto genetic differences in alcohol drinking. Conclusions:, Alcohol-naïve outbred mice selected for high-alcohol drinking were more impulsive with saccharin reinforcers than low-alcohol drinkers. These data are consistent with results seen using inbred strain descendents of high-alcohol drinking and low-alcohol drinking rat lines, and suggest that impulsivity is a heritable difference that precedes alcoholism. [source] An Introduction to Spatial DiscountingJOURNAL OF REGIONAL SCIENCE, Issue 1 2001Charles Perrings Research on the valuation of environmental externalities shows that decision makers tend to discount not only over time but across space. Just as time discounting has implications for intergenerational equity, geographical or spatial discounting has implications for intragenerational equity. Similarly, just as positive time discount rates are warranted by positive net rates of growth of the capital stock, positive spatial discount rates may be warranted by the fact that enviironmental (or other external effects of economic activity are diffused at positive rates. This paper introduces the notion of spatial discounting and explores its welfare implications through a simple diffusion model. [source] Judgmental Discounting and Environmental Risk Perception: Dimensional Similarities, Domain Differences, and Implications for SustainabilityJOURNAL OF SOCIAL ISSUES, Issue 1 2007Alexander Gattig Environmental risks constitute a special category of risks because they often involve consequences that are highly uncertain, strongly delayed, occurring at distant places, and,therefore,mostly borne by others. Economic, decision,theoretic, and psychological research about the way people deal with such consequences is reviewed. Two major findings are presented: first, there is evidence that discounting mechanisms are stable across different preference dimensions (uncertainty, temporal, spatial, and social distance). Second, discount rates tend to vary across different problem domains (e.g., environmental vs. health vs. financial risks). In particular, it appears that temporal discounting is less pronounced for environmental risks than in other domains. Several factors are identified that affect the nature of the risk evaluation process, and it is argued that environmental risks differ from other risks on such factors. These environmental-risk characteristics may have important implications for policy strategies to promote environmental sustainability. Contrary to other domains, appealing to the public's long-term preferences may be successful. Also in policy making, insights from standard economic decision theory to environmental decision making should be applied with caution. [source] | ||||||||||||||||||||||