公共物品供给“志愿者困境”博弈的实验经济学研究

Experimental Examination on “Volunteers’ Dilemma” Game of Public Goods Supply

公共物品供给问题是经济学中有关个人理性与社会困境的经典问题。在公共物品供给博弈中,至少有一个人提供公共物品(志愿服务)是最优结果,但往往出现个体理性与集体理性不相容、个人最优选择与集体最优选择相背离的现象,导致公共物品供给要么缺失、要么过剩的"双重困境",即"志愿者困境"问题。自20世纪70年代以来,实验经济学方法被引入公共物品问题的研究,并逐渐成为一种主流前沿的手段。有关公共物品自愿缴费机制的实验成为这一领域的主流范式,大量实验表明人群中普遍存在稳定的偏好类型和条件性合作行为。本文在文献梳理的基础上,引入不确定性和异质性,利用实验经济学方法,研究不对称成本对"志愿者困境"博弈结果的影响,分析信息在博弈中的作用及条件性合作行为的可能性。结果发现:(1)博弈者供给公共物品的有效性和可靠性可能出现不一致的"反直观"结果;(2)不确定性对博弈者决策行为具有重要影响,信息越透明、越充分,个人行为越接近纳什均衡策略的直观结果;(3)对其他博弈者成本的不确定性会增强志愿服务行为的激励,进而存在提高公共物品供给效率的潜在可能;(4)个体异质性与信息不对称使得博弈者协调合作的可能性很低,出现公共物品供给过剩的"第二重困境",导致集体福利无法实现帕累托改进。

The supply of public goods is a classical problem in economics concerning individual rationality and social dilemma. In the game of public goods supply,at least one person is willing to provide public goods( volunteer service) is the best result,but there are often incompatible phenomena between individual rationality and collective rationality,and between individual optimum choice and collective optimum choice,leading to the "double dilemma"of public goods supply,that is,the "volunteer dilemma". Since the 1970 s,experimental economics was introduced into the study of public goods,and has gradually become a mainstream frontier means. Experiments on voluntary contribution mechanism of public goods have become the mainstream paradigm in this field. A large number of experiments show that there are stable preference types and conditional cooperative behavior in the population. On the basis of literature review,this paper introduces uncertainty and heterogeneity of subjects,studies the effect of asymmetric cost on the results of"volunteer dilemma"game by means of experimental economics,and analyses the role of information in game and the possibility of conditional cooperative behavior. The results show that:( 1) The effectiveness and reliability of public goods supply may be inconsistent or "anti-intuitive".( 2) Uncertainty has an important impact on decision-making of gamers. The more transparent and sufficient the information,the closer the personal behavior is to the intuitive result of the Nash equilibrium strategy.( 3) The uncertainty of the cost of other players will enhance the incentive of voluntary service behavior,and then there is a potential possibility to improve the efficiency of public goods supply.( 4) The heterogeneity of individuals and the asymmetry of information make the possibility of coordination and cooperation very low,which leads to the "second dilemma"of excess supply of public goods. The welfare of the organism cannot obtain Pareto improvement.