搭便车行为、心理与控制：来自经济学实验的证据

To solve the problem that we still lack experimental evidences to support the necessary and sufficient condition in which free riding behavior would take place, the problem that disputes still exist when we try to conclude the effects of both factors in neo-classical model and factors of social preference on free riding, and the problem that free riding's psychological causes of and their action mechanism are unclear, We will conduct economics experiments by Z-tree tool to analyze why free riding behavior happens, when it changes, and how to control it. We will build standard experiment that is benchmark of following experiments, create mathematical function to measure the severity of free riding, and built "natural-skewed" system to convert external variables into behavior variables. We will design controlled experiments to substantiate the presence of free riding psychology, and find out which theory can explain the origin of free riding psychology: the theory of "black slate" or the theory of "genetic determinism". For current controversies, we will conduct judgment experiments to get the truth. External factors and psychological factors that affect the free riding behavior will be gained through the method of factor regression analysis; then we will find the path and structure pattern where external factor converts into psychological factor which in turn affects free riding behavior, and then explain how psychological factor forms and what's its effect. We will conduct controlled experiments to examine the impact of control mechanisms on free riding behavior, such as punishment, award, compensation, information disclosure, discussion, and competition. Choosing control cost, collective benefit and control speed as the optimization objectives, we will study the optimal control model. So this project has important value both in theory and in practice.

针对搭便车行为发生的充要条件缺乏实验证据，新古典模型因素和社会偏好因素影响搭便车行为的结论存在争议，搭便车心理成因及其作用机理尚不明确等问题，本项目采用经济学实验方法，重新审视搭便车行为的产生、变化和防控规律。采用Z-tree工具设计标准实验，作为后续实验的基准；构建模型测量搭便车行为严重程度；构建"自然-偏态"分析体系，实现外在变量到行为变量的转化；设置对照实验，证明搭便车心理存在性，验证搭便车心理缘起是先天论或是后天论；针对现存争议设置判决实验，获得真相；通过因子回归研究影响搭便车行为的外在因子和心理因子，找到外在因子作用于心理因子进而影响搭便车行为的路径和结构，解释搭便车行为的心理成因和及其作用关系。设置对照实验，分析惩罚、奖励、补偿、信息公开、讨论、竞争等机制对搭便车行为的控制效果，并以控制成本、集体收益和控制速度为优化目标，研究搭便车最优控制模型。

本项目对L-D实验进行改进，引入搭便车系数的概念。通过对搭便车实验的设计，我们将受试群体分为少年组、青年组、中年组、老年组四个部分，发现搭便车行为主要是后天可调的，而不是先天不变的。本项目还通过理论推导和实验探索，得到搭便车行为产生的理论阀值，并使用两人博弈的方式进行了实证检验，理论与实证结果基本一致。本项目在大数据的支持下，探索了搭便车行为的内外双向影响因素，包括个人特征因素和外在控制因素。为得到搭便车行为的最优控制模型，本项目从奖惩两种机制入手，同时引入监管方式和惩罚效力的概念，探索提高搭便车行为控制效率的方式。本项目发现不同补偿机制对搭便车行为的影响不同，随着补偿力度增大，抑制作用也逐渐增强。通过上述研究，本项目已经在搭便车心理分析、搭便车影响因素分析、搭便车产生条件、搭便车的控制模型等多个方面取得了相应成果。此外,本项目还在环保车购买、社会捐献等方面。研究发现高于基准值的社会捐赠信息结合物质奖励对环保捐款搭便车行为的抑制最为有效，而低于基准值的社会捐献信息结合精神奖励反而会加重环保捐款搭便车行为。宣传力度能够影响环保车购买中的搭便车行为。不同的框架效应下的宣传对人们减少搭便车行为的影响程度不同。收益框架效应、适度的宣传力度和上行社会信息的宣传能够最有效地减少环保车购买中的搭便车行为。