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Although many decisions involve a stream of payoffs over time, political scientists have given little attention to how actors make the required tradeoffs between present and future payoffs, other than applying the standard exponential discounting model from economics. After summarizing the basic discounting model, we identify some of its leading behavioral anomalies—declining discount rates; preference reversals; higher discount rates for smaller payoffs than for larger payoffs and for gains than for losses; framing effects based on expectations; and a preference for ascending rather than descending sequences. We examine the leading alternative models of discounting and then apply a quasi-hyperbolic discount model to the problem of cooperation in iterated Prisoner's Dilemma games. We demonstrate that if actors display the widely observed tendency to highly discount the immediate future, then cooperation in an iterated Prisoner's Dilemma game is more difficult than Axelrod suggests.

The equivalence of two elicitation methods (sequences and matching) has been assumed when empirically testing the traditional discounting model even though the respective literature has revealed results that are dependent on the procedure used. Three common anomalies revealed (gain/loss asymmetry, short/long asymmetry, and the absolute magnitude effect) are investigated using the two different methods in a within-subjects experiment. In both procedures, it appears that the participants in this study evaluate monetary outcomes over time differently than the discounting model predicts. Patterns consistent with two of the anomalies (gain/loss and absolute magnitude effect) surface and interact in both elicitation techniques. Finally, a systematic inconsistency exists between the two methods. We observe significantly more consistency between the two elicitation techniques when the outcome is a gain in the relatively far future than when it is a future loss. This may be due to the participants' inability to display a preference for spreading losses, which they revealed in the sequences task, in the matching task.

In the last twenty years a growing body of experimental evidence has posed a challenge to the standard Exponential Discounting Model of choice over time. Attention has focused on some specific 'anomalies', notably preference reversal and declining discount rates, leading to the formulation of the model of hyperbolic discounting which is finding increasing favour in the literature. In this paper we provide a survey of both the theoretical modelling and the experimental evidence relating to choice over time. As we will show, a careful analysis of the mapping between theoretical models and experimental investigations raises questions as to whether some of the most focused upon anomalies should be indeed classified as such, or whether they are really the most challenging ones for conventional theory. New developments are emerging both at the theoretical and empirical level, opening up new exciting avenues for investigation.

Policymakers often make decisions involving human-mortality risks and monetary outcomes that span across different time periods and horizons. Many projects or environmental-regulation policies involving risks to life, such as toxic exposures, are experienced over time. The preferences of individuals on lives lost or saved over time should be understood to implement effective policies. Using a within-subject survey design, we investigated our participants' elicited preferences (in the form of ratings) for sequences of lives saved or lost over time at the participant level. The design of our study allowed us to directly observe the possible preference patterns of negative time discounting or a preference for spreading from the responses. Additionally, we embedded factors associated with three other prevalent anomalies of intertemporal choice (gain/loss asymmetry, short/long asymmetry, and the absolute magnitude effect) into our study for control. We find that our participants exhibit three of the anomalies: preference for spreading, absolute magnitude effect, and short/long-term asymmetry. Furthermore, fitting the data collected, Loewenstein and Prelec's model for the valuation of sequences of outcomes allowed for a more thorough understanding of the factors influencing the individual participants' preferences. Based on the results, the standard discounting model does not accurately reflect the value that some people place on sequences of mortality outcomes. Preferences for uniform sequences should be considered in policymaking rather than applying the standard discounting model.

Contents -- Contributors -- Preface -- Part One: Historical Overview -- 1. The Fall and Rise of Psychological Explanations in the Economics of Intertemporal Choice - George Loewenstein -- 2. Intertemporal Choice and Political Thought - Jon Elster -- Part Two: General Perspectives -- 3. Hyperbolic Discounting - George Ainslie and Nick Haslam -- 4. Irrationality, Impulziveness, and Selfishness as Discount Reversal Effects - Howard Rachlin and Andres Raineri -- 5. Anomalies in Intertemporal Choice: Evidence and an Interpretation - George Loewenstein and Drazen Prelec

A considerable body of work in political science is built upon the assumption that politicians are more purposive, strategic decision makers than the citizens who elect them. At the same time, other work suggests that the personality profiles of office seekers and the environment they operate in systematically amplifies certain choice anomalies. These contrasting perspectives persist absent direct evidence on the reasoning characteristics of representatives. We address this gap by administering experimental decision tasks to incumbents in Belgium, Canada, and Israel. We demonstrate that politicians are as or more subject to common choice anomalies when compared to nonpoliticians: they exhibit a stronger tendency to escalate commitment when facing sunk costs, they adhere more to policy choices that are presented as the status-quo, their risk calculus is strongly subject to framing effects, and they exhibit distinct future time discounting preferences. This has obvious implications for our understanding of decision making by elected politicians.

This article describes the previous laws on dangerous dogs (particularly the Law of 6 January 1999) and their practical application, as well as the main provisions of the Law of 5 March 2007 and its consequences. From now on, dogs whose owners do not fulfil all the legal requirements will be considered as posing a serious and immediate threat which may lead to their euthanasia within 48 hours. Increasing constraints are imposed on owners of 1st and 2nd category dogs according to French law, including a behavioural evaluation of their animal, and liability for the costs of capturing and transporting the dog. The responsibility of maires has been changed and increased. Likewise, the responsibility and duties of veterinary surgeons in the control of dangerous dogs tend to increase as well. The Law of 5 March 2007 on the prevention of delinquency completes the Dangerous Dogs Law of 6 January 1999. Consequently, a special legislation on dangerous dogs is slowly being put into place (liability for the actions of animals and criminal offences), based on general law. To understand the importance of these changes, the previous laws and regulations are described, and the main changes brought by the new law are examined. ; Après un rappel de la législation antérieure et de son application pratique (loi n° 99-5 du 6 janvier 1999, en particulier), cette communication fait état des principales dispositions de la loi n° 2007-297 du 5 mars 2007 et de leurs conséquences. Les chiens, dont les propriétaires ne remplissent pas toutes les conditions exigées par la loi, sont désormais considérés comme présentant un danger grave et immédiat qui peut conduire à leur euthanasie sous 48 heures. Les contraintes imposées aux propriétaires de chiens de 1re et 2e catégories s'accroissent: évaluation comportementale de leur animal, mise à leur charge des frais de capture et de transport. Les maires voient l'exercice de leurs responsabilités modulé, tout en étant renforcé. Le rôle du vétérinaire, acteur de ce dispositif, évolue vers un accroissement de sa responsabilité et de ses obligations. La loi du 5 mars 2007, relative à la prévention de la délinquance, vient compléter le dispositif législatif relatif aux chiens dangereux, mis en place par la loi du 6 janvier 1999. À partir du droit général (responsabilité du fait des animaux et infractions pénales), un droit spécial relatif aux chiens dangereux commence de se constituer. Afin de comprendre l'importance de cette évolution, un rappel est donné sur la législation et la réglementation préexistantes, avant d'examiner les principales modifications apportées par la nouvelle loi.

How should policy analysts assess 'benefit validity' when behavioral anomalies appear relevant? David L. Weimer provides thoughtful answers through practical guidelines. Behavioral economists have identified a number of situations in which people appear not to behave according to the neoclassical assumptions underpinning welfare economics and its application to the assessment of the efficiency of proposed public policies through cost-benefit analysis. This book introduces the concept of benefit validity as a criterion for estimating benefits from observed or stated preference studies, and provides practical guidelines to help analysts accommodate behavioral findings. It considers benefit validity in four areas: violations of expected utility theory, unexpectedly large differences between willingness to pay and willingness to accept, non-exponential discounting, and harmful addiction. In addition to its immediate value to practicing policy analysts, it helps behavioral economists identify issues where their research programs can make practical contributions to better policy analysis

Abstract
It is increasingly evident that climate sustainability depends not only on societal actions and responses, but also on ecosystem functioning and responses. The capacity of global ecosystems to provide services such as sequestering carbon and regulating hydrology is being strongly reduced both by climate change itself and by unprecedented rates of ecosystem degradation. These services rely on functional aspects of ecosystems that are causally linked—the same ecosystem components that efficiently sequester and store carbon also regulate hydrology by sequestering and storing water. This means that climate change adaptation and mitigation must involve not only preparing for a future with temperature and precipitation anomalies, but also actively minimizing climate hazards and risks by conserving and managing ecosystems and their fundamental supporting and regulating ecosystem services. We summarize general climate–nature feedback processes relating to carbon and water cycling on a broad global scale before focusing on Norway to exemplify the crucial role of ecosystem regulatory services for both carbon sequestration and hydrological processes and the common neglect of this ecosystem–climate link in policy and landscape management. We argue that a key instrument for both climate change mitigation and adaptation policy is to take advantage of the climate buffering and regulative abilities of a well-functioning natural ecosystem. This will enable shared benefits to nature, climate, and human well-being. To meet the global climate and nature crises, we must capitalize on the importance of nature for buffering climate change effects, combat short-term perspectives and the discounting of future costs, and maintain or even strengthen whole-ecosystem functioning at the landscape level.

Significance Statement
Natural ecosystems such as forests, wetlands, and heaths are key for the cycling and storage of water and carbon. Preserving these systems is essential for climate mitigation and adaptation and will also secure biodiversity and associated ecosystem services. Systematic failure to recognize the links between nature and human well-being underlies the current trend of accelerating loss of nature and thereby nature's ability to buffer climate changes and their impacts. Society needs a new perspective on spatial planning that values nature as a sink and store of carbon and a regulator of hydrological processes, as well as for its biodiversity. We need policies that fully encompass the role of nature in preventing climate-induced disasters, along with many other benefits for human well-being.