Hyperbolic discounting and the standard model: Eliciting discount functions

Experiments on static intertemporal choice find evidence of particularly extreme impatience toward immediate rewards. While this is often taken as support for hyperbolic discounting, it could also arise because the most likely participants in experiments may be those with the most immediate need for money. We conduct a calibration exercise and find that the extreme impatience observed in experiments can be accommodated by a standard exponential discounting model with no discounting and expectation of a ‘small’ increase in the base consumption level. The calibration uses existing estimates of curvature of utility.     

An extension of quasi-hyperbolic discounting to continuous time

Two-Stage Exponential (TSE) discounting, the model developed here, generalises exponential discounting in a parsimonious way. It can be seen as an extension of Quasi-Hyperbolic discounting to continuous time. A TSE discounter has a constant rate of time preference before and after some threshold time; the switch point. If the switch point is expressed in calendar time, TSE discounting captures time consistent behaviour. If it is expressed in waiting time, TSE discounting captures time invariant behaviour. We provide preference foundations for all cases, showing how the switch point is derived endogenously from behaviour. We apply each case to Rubinstein's infinite-horizon, alternating-offers bargaining model.     

消费文化、认知偏差与消费行为偏差

本文放松了理性经济人假设,在行为经济学双曲线贴现模型框架下,以"自我控制"认知偏差及相应的模型参数设定对东西方消费文化差异进行了技术表达,进而阐明了消费过度(欧美国家)和消费不足(东亚国家)这两类消费行为偏差的形成机制。本文采用全球48个国家和地区1978—2007年的面板数据,以儒家虚拟变量和性生活指数作为消费文化的替代变量检验了文化与消费的关系。结果表明,在解释东西方消费率差异时,预防性储蓄等传统理论的解释力远低于不可观测的国家个体效应。儒家虚拟变量和性生活指数能分别解释国家个体效应的28%和58%。这表明消费文化等不随时间改变的个体因素比传统变量更能解释各国居民的消费差异。实践层面上,双曲线贴现模型中锁定技术能有效纠正"自我控制"认知偏差,从而消解儒家文化对消费的深度抑制,可为扩大内需政策创新提供思路启发和技术支撑。     

Multiple solutions under quasi-exponential discounting

Infinite horizon dynamic optimization problems with non-exponential time preferences may not only exhibit time inconsistency but may also have multiple solutions with distinct payoffs. We here show that such multiplicity is generic in the sense that it occurs in an open set of such decision problems, even with small state- and action-spaces. Non-exponential discounting allows for an “addictive” equilibrium alongside a “virtuous” equilibrium. We also provide a sufficient condition for uniqueness in infinitely repeated decision problems with general action spaces. Authors thank Philippe Jehiel, Maria Saez-Marti and Bill Sandholm for comments to an earlier version, and the Knut and Alice Wallenberg Research Foundation for financial support.     

Inter-gender interaction and communication in ultimatum games

In this article, we focus on bargaining within male–female pairs, the most pervasive partnership in humankind. We analyse data from an ultimatum game played by Greek participants. Parallel to this, we introduce a one-way communication protocol according to which the responders can send short messages to the receivers, after making their decisions. The analysis shows that gender and message effects exist and males are more effective bargainers.     

Folk Theorem For Bilateral Bargaining with Vector Endowments

We analyse a bargaining game of two players on the division of the sum of their vector endowments, with alternating proposals and discounting of single period utilities. The pair of endowments is not weakly Pareto‐efficient. Until they reach an agreement, each of the parties can withdraw from bargaining and keep their endowments. Any strictly individually rational division of the sum of endowments can emerge in some subgame perfect equilibrium if discount factors are close enough to one. Each subgame perfect equilibrium, in which the parties’ decisions do not depend on past rejected proposals, leads to a weakly Pareto‐efficient agreement in the first period.     

An economic reappraisal of the Melamchi water supply project - Kathmandu,Nepal

This paper examines whether the benefits of the Melamchi water supply project in Nepal are likely to exceed its costs, assuming that high-quality municipal water services can be delivered to households and firms in the urbanized part of the Kathmandu Valley. Monte Carlo simulations are used to explore the sensitivity of the net present value and economic internal rate of return calculations to a wide range of assumptions and input parameters. We find that extreme assumptions are not required to generate large differences in economic feasibility; quite plausible differences in the values of some key parameters can lead to large differences in the economic attractiveness of the project. The results reveal that the three most important influences on net present value and economic internal rate of return are: (i) the discount rate and discounting procedure; (ii) the magnitude of monthly benefits for households connected to the new water system; and (iii) the annual growth rate in monthly benefits of connected households after the project comes on line. Our contribution lies in illustrating, with an actual case study in a developing country, the degree to which cost-benefit calculations of large infrastructure projects are influenced by key economic modeling assumptions and input parameters.JEL Classification: H42, H43, H54, Q25, Q56 Correspondence to: Dale WhittingtonWe would especially like to thank Keiichi Tamaki (ADB) and Ian Hill (Acres International) for their guidance and assistance with this project. We would also like to thank the following individuals for their help during our mission to Kathmandu in May, 2003: Richard W. A. Vokes, Kathie M. Julian, Raj Kumar Malla, Madan Shankar Shrestha, Suman Prasad Sharma and Noor Kumar Tamrakar.     

Collective rent seeking and division of labor

The article analyzes division of labor within multiple groups engaged in collective rent seeking through time. Each agent seeks membership in one of two subgroups within each group, conveniently labelled a leader-subgroup and a follower-subgroup. The within-group generated payoffs are used as input in the between-group competition for the other groups' payoffs and an external rent. Within-group egalitarian allocation, but not relative-effort allocation, alleviates leadership struggle if the rent is large or the group is moderately more decisive than the other groups. The group employing a more egalitarian sharing rule than the other groups alleviates its leadership struggle more successfully. The Folk theorem is used to show the conditions under which leadership struggle gets intensified or alleviated.     

Collective rent seeking and division of labor

The article analyzes division of labor within multiple groups engaged in collective rent seeking through time. Each agent seeks membership in one of two subgroups within each group, conveniently labelled a leader-subgroup and a follower-subgroup. The within-group generated payoffs are used as input in the between-group competition for the other groups' payoffs and an external rent. Within-group egalitarian allocation, but not relative-effort allocation, alleviates leadership struggle if the rent is large or the group is moderately more decisive than the other groups. The group employing a more egalitarian sharing rule than the other groups alleviates its leadership struggle more successfully. The Folk theorem is used to show the conditions under which leadership struggle gets intensified or alleviated.