Experimental economics is the application of
experimental methods to study economic questions. Experiments are
used to test the validity of economic theories and test-bed new
market mechanisms. Using cash-motivated subjects, economic
experiments create real-world incentives to help us better
understand why markets and other exchange systems work the way they
do. Experiments may be conducted in laboratory settings or in the
field. Also see Simulations and games in economics education.
Experimental topics
Economics experiments can be loosely classified into the following
topics:
Markets,
Games,
Decision making,
Bargaining,
Auctions,
Coordination, Social Preferences, Learning,
Matching, and Field Experiments.
Coordination games
Coordination games are games with multiple pure strategy nash
equilibria. There are two general sets of questions that
experimental economists typically ask when examining such games:
(1) Can laboratory subjects coordinate, or learn to coordinate, on
one of multiple equilibria, and if so are there general principles
that can help predict which equilibrium is likely to be chosen? (2)
Can laboratory subjects coordinate, or learn to coordinate, on the
Pareto best equilibrium and if not, are there conditions or
mechanisms which would help subjects coordinate on the Pareto best
equilibrium? Deductive selection principles are those that allow
predictions based on the properties of the game alone. Inductive
selection principles are those that allow predictions based on
characterizations of dynamics.
Learning Experiments
In games of two players or more, the subjects often form beliefs
about what actions the other subjects are taking and these beliefs
are updated over time. This is known as belief learning. Subjects
also tend to make the same decisions that have rewarded them with
high payoffs in the past. This is known as reinforcement
learning.
Until the 1990s, simple adaptive models, such as Cournot best
response or
fictitious play, were
generally used. In the mid-1990s,
Alvin
E. Roth and Ido Erev demonstrated
that reinforcement learning can make useful predictions in
experimental games. In 1999,
Colin
Camerer and Teck Ho introduced
Experience Weighted
Attraction (EWA), a general model that incorporated
reinforcement and belief learning, and shows that fictitious play
is mathematically equivalent to generalized reinforcement, provided
weights are placed on past history.
Criticisms of EWA include overfitting due to many parameters, lack
of generality over games, and the possibility that the
interpretation of EWA parameters may be difficult. Overfitting is
addressed by estimating parameters on some of the experimental
periods or experimental subjects and forecasting behavior in the
remaining sample (if models are overfitting, these out-of-sample
validation forecasts will be much less accurate than in-sample
fits, which they generally are not). Generality in games is
addressed by replacing fixed parameters with "self-tuning"
functions of experience, allowing pseudo-parameters to change over
the course of a game and to also vary systematically across
games.
Modern experimental economists have done much notable work
recently. Roberto Weber has raised issues of learning without
feedback. David Cooper and John Kagel have investigated types of
learning over similar strategies. Ido Erev and Greg Barron have
looked at learning in cognitive strategies. Dale Stahl has
characterized learning over decision making rules.
Charles A. Holt has studied logit learning in different
kinds of games, including games with multiple equilibria. Wilfred
Amaldoss has looked at interesting applications of EWA in
marketing. Amnon Rapoport,
Jim Parco and
Ryan Murphy have investigated reinforcement-based adaptive learning
models in one of the most celebrated paradoxes in game theory known
as the
centipede game.
Market games
Vernon Smith conducted pioneering
economics experiments on the convergence of prices and quantities
to their theoretical competitive equilibrium values in experimental
markets. Smith studied the behavior of "buyers" and "sellers", who
are told how much they "value" a fictitious commodity, and then are
asked to competitively "bid" or "ask" on these commodities
following the rules of various real world market institutions, such
as the
Double auction (both sides can
bid) used in many stock exchanges, as well the English auction and
the Dutch auction (see
Auctions). Smith
found that in some forms of centralized trading, prices and
quantities traded in such markets converge on the values that would
be predicted by the economic theory of
perfect competition, despite the
conditions not meeting many of the assumptions of perfect
competition (large numbers, perfect information).
Over the years, Smith pioneered -along with other collaborators-
the use of controlled laboratory experiments in economics, and
established it as a legitimate tool in economics and other related
fields.
Charles Plott of
the California Institute of
Technology
collaborated with Smith in the 1970s and pioneered
experiments in political science, as well as using experiments to
inform economic design or engineering to inform policies. In
2002, Smith was awarded (jointly with
Daniel Kahneman) the
Bank of Sweden Prize in Economic Sciences "for having
established laboratory experiments as a tool in empirical economic
analysis, especially in the study of alternative market
mechanisms".
Finance
Experimental finance studies
financial markets with the goals
of establishing different market settings and environments to
observe experimentally and analyze agents' behavior and the
resulting characteristics of trading flows, information diffusion
and aggregation, price setting mechanism and returns processes.
Presently, researchers use simulation software to conduct their
research.
For instance, experiments have manipulated
information asymmetry about the
holding value of a bond or a share on
the pricing for those who don't have enough information, in order
to study
stock market
bubbles.
Social preferences
The term "social preferences" refers to the concern (or lack
thereof) that people have for each other's well-being, and it
encompasses altruism, spitefulness, tastes for equality, and tastes
for reciprocity. Experiments on social preferences generally study
economic games including the
dictator
game, the
ultimatum game, the
trust game, the
public goods game, and modifications to
these canonical settings.As one example of results,
ultimatum game experiments have shown that
people are generally willing to sacrifice monetary rewards when
offered low allocations, thus behaving inconsistently with simple
models of self-interest. Economic experiments have measured how
this deviation varies across cultures. (More market-oriented
societies tend to have higher
inequity
aversion.)
Methodology
Guidelines
Experimental economists generally adhere to the following
methodological guidelines:
- Incentivize subjects with real monetary payoffs.
- Publish full experimental instructions.
- Do not use deception.
- Avoid introducing specific, concrete context.
Critiques
The above guidelines have developed in large part to address two
central critiques. Specifically, economics experiments are often
challenged because of concerns about their "internal validity" and
"external validity", for example, that they are not applicable
models for many types of economic behavior, so the experiments
simply aren't good enough to produce useful answers.
See also
References
- [C.F. Bastable] (1987). "experimental methods in economics," i,
The New
Palgrave: A Dictionary of Economics, v. 2, pp. 241.
Reprinted from Palgrave's Dictionary of Political Economy
(1925).
- Vernon L. Smith (1987). "experimental methods in economics,"
ii, The New Palgrave: A Dictionary of Economics, v. 2,
pp. 241–49.
- _____ (2008a). "experimental methods in economics."
The New
Palgrave Dictionary of Economics, 2nd Edition, Abstract.
- _____ (2008b). "experimental economics," The New Palgrave
Dictionary of Economics, 2nd Edition, Abstract.
External links
Experimental economics organizations
- Economic Science Association, the international
association of experimental economists.
- Research
Chair Antoni Serra Ramoneda Caixa Catalunya, Barcelona, Spain
(ASR)
- Computable and Experimental Economics Laboratory at
University of Trento, Italy (CEEL)
- Economics
Research Laboratory at Texas A&M University (ERL-TAMU)
- CentERlab,
Tilburg University, the Netherlands
- Experimental Economics Laboratory at University of
Maryland (EEL-UMD)
- ICES,
Interdisciplinary Center for Economic Science at George Mason
University
- (ESI)
Economic Science Institute at Chapman University
- Madrid Laboratory for Experimental Economics
(MadLEE), at Universidad Autónoma de Madrid
- xs/fs,
Experimental Social Science at Florida State University
- Magdeburg Laboratory for Experimental Economics
- Erfurt
Laboratory for Experimental Economics
- Bonn Experimental Economics Laboratory
- UC Berkeley
Experimental Economics - Xlab
- Center
for Research in Experimental Economics and political
Decision-making (CREED) at Universiteit van Amsterdam
- Laboratory
for Experimental Economics and Political Science (EEPS) at
California Institute of Technology
- Center for
Experimental Social Science (CESS) at NYU
- Social
Science Experimental Laboratory (SSEL) at Caltech
- California
Social Science Experimental Laboratory (CASSEL) at UCLA
- Pittsburgh
Experimental Economics Lab (PEEL) at University of
Pittsburgh
- University of Arizona Economic Science Laboratory
- Learning and
Experimental Economics Projects (LEEPS) at UCSC
- Interdisciplinary Center for Economic Science
(ICES)
- Centre for Decision Research and Experimental Economics
(CeDEx)
- Laboratoire Montpelliérain d'Economie Expérimentale (LEEM)
LEEM's Laboratory (France)
- Finance and Economics Experimental Laboratory at Exeter
(FEELE), Exeter University, UK
- Laboratory of Social and Economic Experiments,
Poland
- French LABoratory of EXperimental Economics
(LABEX)
- Bell University Laboratory in Electronic Commerce
and Experimental Economics at CIRANO
- Bilgi
Economics Lab of Istanbul (BELIS) at Istanbul Bilgi
University
- Laboratory for experimental and behavioural economics
at State
University - Higher School of Economics, Russia
Software
Education