| 714 | 8 | 72 |
| 下载次数 | 被引频次 | 阅读次数 |
经济学正日渐走向实验化。这一趋向的出现与实验经济学家致力于发展一整套契合经济学研究范式的方法体系密切相关。本文围绕经济学家为什么做实验,实验研究是否有效,以及如何增进实验研究的有效性这三个层层递进的问题,系统地梳理了实验经济学诞生以来的方法论争论。结果发现,学者们虽然已在实验方法性质和意义的理解上达成一致,但在实验内部有效性和外部有效性问题上的争论仍在继续。不过,随着越来越多的实验研究者开始关注方法论问题,并从经验上探究影响实验研究有效性的因素,实验经济学中的方法论讨论正走向全新的阶段,学者们对经济学实验研究边界和局限性的理解也日益精致。
Abstract：Experimentation has a significant role in prominence in economics. The trend is largely due to experimental economists' continuous efforts on developing the experimental methods that correspond to economic research paradigm. This article reviews such efforts and related debates on experimental methodology around three questions,why do experiments be in economics,whether the experiments are valid,and how to enhance their validity. The results show that although substantial agreements on the nature and significance of experimentation are achieved,there are still debates on the internal validity and external validity. However,more and more experimental economists get involved in the methodology,they agree that it is helpful to better understand the boundaries and limits of various experimental approaches by investigating the determinants of the validity of experiment researches.
1 .Becker,G.M.,M.H.De Groot and J.Marschak,“Measuring Utility by a Single-Response Sequential Method”,Behavioral Science,1964,9(3):226-232.
2 .Bolton,G.,“Testing Models and Internalizing Context:A Comment on‘Theory and Experiment:What Are the Questions?’”,Journal of economic behavior&organization,2010,73(1):16-20.
3 .Camerer,C.,“The Promise and Success of LabField Generalizability in Experimental Economics:A Critical Reply to Levitt and List”,Available at SSRN 1977749,2011.
4 .Camerer,C.F.and R.M.Hogarth,“The Effects of Financial Incentives in Experiments:A Review and CapitalLabor-Production Framework”,Journal of Risk and Uncertainty,1999,19(1):7-42.
5 .Campbell,D.T.and J.C.Stanley,Experimental and Quasi-Experimental Designs for Research,Chicargo:Rand Mc Nally,1966.
6 .Card,D.,S.Della Vigna and U.Malmendier,“The Role of Theory in Field Experiments”,Journal of Economic Perspectives,2011,25(3):39-62.
7 .Cardenas,J-C.,Bringing the Lab to the Field:More Than Changing Subjects,Working paper,available at The Field Experiments Website,2004.
8 .Charness,G.and P.Kuhn,“Lab Labor:What Can Labor Economists Learn from the Lab?”,In O.Ashenfelt and D.Card(ed.),Handbook of Labor Economics,2011,4:229-330.
9 .Croson,R.,“Why and How to Experiment:Methodologies from Experimental Economics”,University of Illinois Law Review,2002,(4):921-946.
10 .Croson,R.and S.Gchter,“The Science of Experimental Economics”,Journal of Economic Behavior&Organization,2010,73(1):122-131.
11 .Davis,D.D.and C.A.Holt,Experimental Economics,Princeton:Princeton University Press,1993.
12 .Dawes,R.M.,“The Purpose of Experiments:Ecological Validity Versus Comparing Hypotheses”,Behavioral and Brain Sciences,1996,19(1):20.
13 .Falk,A.and J.J Heckman,“Lab Experiments Are a Major Source of Knowledge in the Social Sciences”,science,2009,326(5952):535-538.
14 .Fisher,R.A.,The Design of Experiments,London:Oliver and Boyd,1935.
15 .Friedman,D.and S.Sunder,Experimental Methods:A Primer for Economists,Cambridge:Cambridge University Press,1994.
16 .Gintis,H.,“Towards a Renaissance of Economic Theory”,Journal of Economic Behavior&Organization,2010,73(1):34-40.
17 .Guala,F.,“Economics in the Lab:Completeness Vs.Testability”,Journal of Economic Methodology,2005,12(2):185-196.
18 .Guala,F.and L.Mittone,“Experiments in Economics:External Validity and the Robustness of Phenomena”,Journal of Economic Methodology,2005,12(4):495-515.
19 .Harrison,G.W.and J.A.List,“Field Experiments”,Journal of Economic Literature,2004,42(4):1009-1055.
20 .Harrison,G.W.,“Field Experiments and Control”,in G.W.Harrison,J.Carpenter,J.A.List(ed.),Field Experiments in Economics(Research in Experimental Economics),Amsterdam:Elsevier,2005,10:17-50.
21 .Harrison,G.W.,“The Behavioral Counter-Revolution”,Journal of economic behavior&organization,2010,73(1):49-57.
22 .Heiner,R.A.,“Experimental Economics:Comment”,The American Economic Review,1985,75(1):260-263.
23 .Hertwig,R.and A.Ortmann,“Experimental Practices in Economics:A Methodological Challenge for Psychologists?”,Behavioral and Brain Sciences,2001,24(3):383-403.
24 .Hogarth,R.M.,“The challenge of representative design in psychology and economics”,Journal of Economic Methodology,2005,12(2):253-263.
25 .Houser,D.and E.Xiao,“Understanding Context Effects”,Journal of economic behavior&organization,2010,73(1):58-61.
26 .Levitt,S.D.and J.A.List,“What Do Laboratory Experiments Measuring Social Preferences Reveal About the Real World?”,The journal of economic perspectives,2007,21(2):153-174.
27 .List,J.A.,“Field Experiments:A Bridge between Lab and Naturally Occurring Data”,The BE Journal of Economic Analysis&Policy,2007,(6)2:1-45.
28 .List,J.A.,“An Introduction to Field Experiments in Economics”,Journal of Economic Behavior&Organization,2009,70(3):439-442.
29 .Loewenstein,G.,“Experimental Economics from the Vantage-Point of Behavioural Economics”,The Economic Journal,1999,109(453):25-34.
30 .Mki,U.,“Models Are Experiments,Experiments Are Models”,Journal of Economic Methodology,2005,12(2):303-315.
31 .Mc Dermott,R.,“Experimental Methodology in Political Science”,Political Analysis,2002,10(4):325-342.
32 .Mill,J.S.,A System of Logic Ratiocinactive and Inductive,Toronto:University of Toronto Press,1973.
33 .Morgan,M.S.,“Experiments Versus Models:New Phenomena,Inference and Surprise”,Journal of Economic Methodology,2005,12(2):317-329.
34 .Ortmann,A.,“Field Experiments in Economics:Some Methodological Caveats”,in G.W.Harrison,J.Carpenter,J.A.List(ed.),Field Experiments in Economics(Research in Experimental Economics),Amsterdam:Elsevier,2005,10:17-50.
35 .Plott,C.R.,“Industrial Organization Theory and Experimental Economics”,Journal of Economic Literature,1982,20(4):1485-1527.
36 .Plott,C.R.,“Dimensions of Parallelism:Some Policy Applications of Experimental Methods”,A.Roth(ed.),Laboratory experimentation in economics:Six points of view,Cambridge:Cambridge University Press,1987:193!219.
37 .Plott,C.R.,“Will Economics Become an Experimental Science?”,Southern Economic Journal,1991,57(4):901-919.
38 .Read,Daniel,“Monetary Incentives,What Are They Good For?”,Journal of Economic Methodology 12,no.2(2005):265-276.
39 .Rice,D.B.and Smith,V.L.,“Nature,the experimental laboratory,and the credibility of hypotheses”,Behavioral Science,1964,9(3):239-246.
40 .Roth,A.,“Laboratory Experimentation in Economics:Six Points of View”,Cambridge:Cambridge University Press,1987.
41 .Roth,A.E.,“Laboratory Experimentation in Economics:A Methodological Overview”,The Economic Journal,1988,98(393):974-1031.
42 .Roth,A.E.,“Lets Keep the Con out of Experimental:A Methodological Note”,Empirical Economics,1994,19(2):279-289.
43 .Roth,A.E.,“Introduction to Experimental Economics”,In J.Kagel and A.Roth(ed.),The handbook of experimental economics,Princeton:Princeton University Press,1995:3-109.
44 .Roth,A.E.,“Game Theory as a Part of Empirical Economics”,The Economic Journal,1991,101(404):107-114.
45 .Roth,A.E.,“The Economist as Engineer:Game Theory,Experimentation,and Computation as Tools for Design Economics”,Econometrica,2002,70(4):1341-1378.
46 .Roth,A.E.,The Theory and Practice of Market Design,Nobel Prize Committee,2012.
47 .Samuelson,L.,“Economic Theory and Experimental Economics”,Journal of Economic Literature,2005,43(1):65-107.
48 .Schelling,TC.,The Strategy of Conflict,London:Cambridge,1960.
49 .Schmidt,K.M.,“The Role of Experiments for the Development of Economic Theories”,Perspektiven der Wirtschaftspolitik,2009,10(1):14-30.
50 .Schram,A.,“Artificiality:The Tension between Internal and External Validity in Economic Experiments”,Journal of Economic Methodology,2005,12(2):225-237.
51 .Shadish,W.R.,T.D.Cook and D.T.Campbell,Experimental and Quasi-Experimental Designs for Generalized Causal Inference,Boston:Houghton Mifflin Company,2002:1-32.
52 .Siegel,S.,“Theoretical Models of Choice and Strategy Behavior:Stable-State Behavior in the Two-Choice Uncertain Outcomes Situation”,Psychometrika,1959,24(4):303-316.
53 .Siegel,S.,“Decision Making and Learning under Varying Conditions of Reinforcement”,Annals of the New York Academy of Sciences,1961,89(5):766-783.
54 .Smith,V.L.,“Experimental Economics:Induced Value Theory”,The American Economic Review,1976,66(2):274-279.
55 .Smith,V.L.,“Microeconomic Systems as an Experimental Science”,The American Economic Review,1982,72(5):923-955.
56 .Smith,V.L.,“Experimental Economics:Reply”,The American Economic Review,1985,75(1):265-272.
57 .Smith,V.L.,“Theory,Experiment and Economics”,The Journal of Economic Perspectives,1989,3(1):151-169.
58 .Smith,V.L.,“Economics in the Laboratory”,The Journal of Economic Perspectives,1994,8(1):113-131.
59 .Smith,V.L.and J.M.Walker,“Monetary Rewards and Decision Cost in Experimental Economics”,Economic Inquiry,1993,31(2):245-261.
60 .Smith,V.L.,“Method in Experiment:Rhetoric and Reality”,Experimental economics,2002,5(2):91-110.
61 .Smith,V.L.,“Theory and Experiment:What Are the Questions?”,Journal of Economic Behavior&Organization,2010,73(1):3-15.
62 .Soberg,M.,“The Duhem-Quine Thesis and Experimental Economics:A Reinterpretation”,Journal of Economic Methodology,2005,12(4):581-597.
63 .Starmer,C.,“Experiments in Economics:Should We Trust the Dismal Scientists in White Coats?”,Journal of Economic Methodology,1999,6(1):1-30.
64 .Sugden,R.,“Experiments as Exhibits and Experiments as Tests”,Journal of Economic Methodology,2005,12(2):291-302.
65 .Thurstone,L.L.,“The Measurement of Social Attitudes”,Journal of Abnormal and Social Psychology,1931,26(3):249-269.
66 .Thye,S.R.,“Logical and Philosophical Foundations of Experimental Research in the Social Sciences”,In M.Webster and J.Sell(ed.),Laboratory experiments in the social sciences,Burlington:Elsevier,2007:57-86.
67 .Tversky,A.and D.Kahneman,“Rational Choice and the Framing of Decisions”,Journal of Business,1986,59(4):251-278.
68 .Wallis,W.A.and M.Friedman,“The Empirical Derivation of Indifference Functions”,O.Lange,F.Mc Intyre and T.O.Yntema(ed.),Studies in mathematical economics and econometrics in memory of Henry Schultz,Chicago:The University of Chicago Press,1942:267!300.
69 .Webster,M.and J.Sell,“Why Do Experiments?”,In M.Webster and J.Sell(ed.),Laboratory experiments in the social sciences,Burlington:Elsevier,2007:5-23.
70 .Willer,D.and H.A.Walker,Building Experiments:Testing Social Theory,Stanford:Stanford University Press,2007.
71 .Zelditch,M.,“The External Validity of Experiments That Test Theories”,In M.Webster and J.Sell(ed.),Laboratory experiments in the social sciences,Burlington:Elsevier,2007:87-112.
72 .丹尼尔·豪瑟、罗卫东、范良聪、杨晓兰:《实验经济学的兴起、发展及其在中国的应用前景》,《浙江大学学报人文社会科学版》2012年第3期。
73 .范良聪:《实验经济学兴起与发展的动力机制研究》,浙江大学博士论文,2010年。
74 .罗卫东、范良聪:《经济学实验的方法论支撑:超越“无关痛痒”的证伪主义》,《浙江社会科学》2010年第5期。
75 .西蒙:《基于实践的微观经济学》,格致出版社2009年版。
1 见List(2009)和Card(2011)提供的统计。
2 Loewenstein(1999)在区分行为经济学和实验经济学时指出,前者考虑的是如何在经济分析中引入心理学理论和视角,与方法无关;后者强调的是控制实验这种研究方法,强调如何发展适于探讨经济问题的实验方法。本文讨论的是实验方法,以实验经济学以及实验经济学家的方法论努力为线索会有助于阐释问题。
3 Vernon Smith获奖的理由之一就是他的方法论贡献。
4 因此许多实验得到的所谓证伪结果是值得商榷的:这很可能是由于实验设计没有捕捉到理论的前提假设。不过Guala(2005)辩驳说,这样的完整性要求过于严苛了。
5 这里值得一说的是因果关系的定义,因为实验研究似乎天然地适于探索因果关系(Shadish et al.,2002)。科学哲学史上对因果关系的定义纷繁复杂,不过总体的趋势是早期学者倾向于把它定义为完美规则(定律),现代学者倾向于把它定义为统计学意义上的概率可能性(Thye,2007)。其实,Guala(2005)认为完整性要求太过严苛就是因为他认为,科学的目的不仅在于构建拥有完整性的理论,还在于探究不完全的因果关系,对于经济学而言尤其如此。
6 Mill(1973[1872])提出了识别因果关系的几种经验方法,其中的求异法就是控制组与比较组思想的原型。但Mill自己反对实验,也许是因为他没有从自己的定义与方法中找到完美规则,因为他提出的方法中存在若干当时无法解决的问题。比如,如何创建两个只有一处不同的环境?如何确保发现的因果关系成为一种完美规则?Fisher的工作拯救了Mill,见Walker与Willer(2007)和Thye(2007)的阐述。
7 Davis和Holt(1993)的描述主要考虑的是实验室实验。近来,田野实验及其特有功能开始受到实验经济学家的重视,比如与实验室和自然发生的数据相互检验,连接理论、实验室与真实世界,为研究者寻找实验室或自然数据研究中遗漏的变量提供线索等(Cardenas,2004;List,2007)。
8 有鉴于寻找边界的稳健性检验在方法论上的重要性,Smith(1982)在类型化时特地把这类实验独立出来。
9 实验尤其是田野实验在衡量现实中难以衡量的变量如偏好、制度绩效等方面的功能得到了诸多学者的一致强调(如Roth,1988,1995;List,2007;Croson and Gchter,2010;Charness and Kuhn,2011)。
10 科学哲学家早就指出,虽然完美的证伪主义不可能实现,但容忍错误的证伪主义还是可能的。当然,这并不排除某些超科学的信念和偏好会导致科学判断中出现系统性偏误(Shadish et al.,2002)。也正是在这个意义上,韦伯那里的价值和意义对于社会科学实验研究而言尤其重要(罗卫东与范良聪,2010)。
Morgan(2005)还强调了实验相比理论的另一种真实性:理论的所有结论都已在假设条件中得到规约,不会生成任何新东西,而实验却常常带来意料之外的结果。Guala和Mittone(2005)也强调了意外发现的重要性,因为它们的出现可能源自非人为的实验因素。
值得注意的是,实验先驱并没有完全忽视其他类型实验研究中的外部有效性问题。比如,Smith(1985)就提到,实验研究不应该局限于检验理论,还需要对真实世界和实验室行为之间的并行性展开经验研究。Plott(1987)更是证明,实验室不仅可以被塑造地接近真实世界的目标体系,得到的结论也可以成功地应用于现实世界。即使批评者如Loewenstein(1999)等也承认,有些实验是有外部有效性的。
典型的表现就是,实验研究者已经发展出许多处理内部有效性问题的工具,但没有发展出多少处理外部有效性问题的工具(Schram,2005;Guala and Mittone,2005)。
在控制之外,实验经济学也在尝试传统的衡量工作,比如Becker等(1964)对保留价格的衡量,其他如对被试支付意愿、风险态度的衡量,控制组和比较组中对因果效应的衡量等。尽管如此,在很多时候,实验也无法实现独立于理论的精确衡量(McD ermott,2002;Shadish et al.,2002)。这也是为何实验研究者偏好控制甚于衡量(Roth,1988)。当然,如前所述,要实现完全的控制也很困难,尤其是因为许多经济学现象的预测都发生在边际上——比如,激励到底要凸显到何种程度才能带来收敛的结果呢?
Hertwig和Ortmann(2001)说到,经济学实验“通过清晰地阐述行动的选择(实验介绍)、允许被试获得经验(重复试验)、让目标变得清晰——即赚得更多(货币激励)、限制关于实验目的的二阶猜测(不欺骗),减少了不确定性”。因此,他们建议心理学家在合乎研究主题的情况下学习经济学家的做法,或者至少养成“两条腿走路”的习惯。
影响内部有效性的主要因素包括样本选择的差异、历史因素的影响、被试学习能力的差异、实验者需求效应或被试预期效应、测量误差、被试的自选择或退出、实验者偏差以及这些因素之间的交互作用等;而影响外部有效性的因素有检验效应、样本代表性、霍桑效应、专业被试、实验者效应等。
Harrison和List(2004)特别强调被试不知道自己正在参加实验的自然田野实验方法在结合良好的控制和真实性上的出色表现。
Cardenas(2004)和Harrison(2010)提出了一个类似的问题,他们考虑的是实验者这一特定的观察者可能给博弈结构带来的实质性影响,比如导致一个两人博弈变成一个两阶段三人博弈:第一阶段是实验者和实验被试的博弈,第二阶段是被试之间的博弈;如此便可能引发被试群体的某种策略性行为,例如把一个竞争博弈变成一个被试合作瓜分实验者提供的禀赋的博弈。
Bolton(2010)以地图为例进行了说明。比如,如果把地铁的地图用于指引步行,那将是灾难,但若用于乘坐地铁,却是方便之极。
还可见如Charness和Kuhn(2011),豪瑟等(2012)。
限于篇幅,本文没有考虑许多围绕实验操作细节展开的讨论,如样本规模、被试征募程序等。这些讨论常见于期刊,也说明了实验经济学家对方法的重视。
基本信息:
DOI：10.14167/j.zjss.2015.06.021
中图分类号:F011
引用信息:
[1]范良聪,张新超.经济学实验的方法论之争[J].浙江社会科学,2015,No.226(06):135-149+160.DOI:10.14167/j.zjss.2015.06.021.
基金信息:
国家社科基金青年项目(立项号:12CJL026,13CJL004);; 浙江省自然科学基金青年项目(立项号:Q14G030046)的阶段性成果;; 国家留学基金委的资助
2015-06-15
2015-06-15