Subject Pool Bias in Economics Experiments

In this paper we consider data from a large number of economic experiments, and look for demographic effects that may be a source of subject pool bias if not carefully accounted for in the subsequent statistical analysis. Our dataset contains information on 2,408 subjects and 597 experimental sessions from 74 experiments recorded over more than 2 years at an experimental laboratory. Using different estimation methods and model specifications, we identify the significant demographic determinants of personal earnings, and find that they account for less than 4% of the observed variation. Thus we deliver empirical evidence supporting the experimental method as monetary incentives, and therefore some kind of strategic behavior, seem to be more important than demographics in the laboratory. Exploiting the timeseries nature of the data we also study some dynamic issues of the subject pool: we analyze the factors that influence subjects’ decisions on returning to the laboratory.Experiments, Subject pool bias, Demographic characteristics

Trust, discrimination and acculturation Experimental evidence on Asian international and Australian domestic university students

Intercultural relations between Australia and Asia are pivotal to the economic prosperity of the Asia-Pacific region. However, there appears to be tension between Australian domestic and Asian international students at universities in Australia. To measure the degree of trust and patterns of discrimination between these groups, the Berg, Dickhaut and McCabe (1995) trust game and a series of control games were used in framework where each participant played each game against several partners. Controlling for individual heterogeneity, domestic students significantly discriminated against international students in the trust game, and individual discrimination was preference-based rather than based on beliefs towards international students’ trustworthiness. Moreover, the degree of in-group favouritism shown by domestic students was negatively correlated with the Big Five personality trait of Openness. Intercultural patterns across the games also pointed to a willingness of international students to build relations with domestic students. However, the average amount that they sent in the trust game was negatively related with the number of semesters studied at university in Australia, which may partly reflect cultural adjustment but also institutional disadvantages faced specifically by international students. The study furthers understanding of the patterns of discrimi-nation between domestic and international university students, the nature of this discrimination, and illustrates the extent of challenges faced by the Australian tertiary education sector.rust, discrimination, intercultural differences, economic experiments

Individual vs. collective contracts: An experimental investigation using the gift exchange game

This paper compares individual with collective contracts using modified repeated gift exchange games. The game had two variations, both following a partner design. In the individual variation different workers in the same firm can receive separate wages, and in the collective variation all workers in the same firm receive the same wage. These two variations are played altering the order. Thus the experiment has four treatments, two within subjects (regarding the games played) and two between subjects (regarding the order in which the games are played). We did not find significant differences between the two variations of the game when subjects had no experience. However, individual agreements turned out to be more efficient when subjects have previously experienced collective agreements. This result suggests subjects learned to reciprocate when they played the collective variation followed by the individual variation of the gift exchange game.laboratory experiments, gift exchange, collective contracts.

On-Campus Housing: Theory vs. Experiment

Many universities in the US offer on-campus housing opportunities to incoming as well as already enrolled students. Recent research has theoretically as well as experimentally shown that the most common student assignment mechanism used in the US is subject to serious efficiency losses. In this paper we first show that a particular mechanism which is currently in use at the MIT for about two decades is in fact equivalent to a natural adaptation of the well-known Gale-Shapley mechanism of two-sided matching theory. Motivated from the increasing popularity and success of the Gale-Shapley mechanism in a number of markets, we next experimentally compare the performances of the MIT mechanism with that of the leading theory mechanism Top Trading Cycles. Contrary to theory, the MIT mechanism performs better in terms of efficiency and participation rates, while we observe no significant difference between the two mechanisms in terms of truth-telling rates .

Efficient inter-group competition and the provision of public goods

We propose an intergroup competition scheme (ICS) to solve the free-riding problem in the public goods game. Our solution only requires knowledge of the group contributions, is budget balanced and with the right parameters a dominant strategy. The main innovations of our design are that the prize to the winning group is paid by the losing group and that the size of the transfer depends on the difference in contribution by the two groups. With the right parameters, this scheme changes the dominant strategy from none to full contribution. We tested different parameterizations for the ICS. The experiments show dramatic gains in efficiency in all the ICS treatments. Moreover, versions of the ICS in which intergroup competition should not change the zero contribution Nash equilibrium also produce remarkable gains in efficiency and no decline in contributions over time.public goods, intergroup competition, team production, voluntary contributions mechanism, economic experiments

Inducing a Self-Fulfilling Prophecy in Public Goods Games.

This study explores how a self-fulfilling prophecy can solve a social dilemma. We ran two experimental treatments, baseline and automata. Both consisted of a finitely repeated public goods game with a surprise restart. In the automata treatment it was announced that there might be automata playing a grim trigger strategy. This announcement became a self-fulfilling prophecy. That is, most participants actually followed a grim trigger strategy in the automata treatment resulting on an increase on the average contributions to the public good relative to the baseline treatment. Moreover, four out of nine groups managed to fully cooperate almost until the last period. Furthermore, after the surprise restart, when the automata threat is less credible, subjects’ behavior was very close to that in the original game.self-fulfilling prophecy, public goods game, grim trigger strategy,cooperation, automata, beliefs.

Raising "lab rats"

Experimental subjects usually self-select to the laboratory and this may introduce a bias to the derived conclusions. We analyze data stored by a subject-pool management software at an experimental laboratory and speculate about the eect of individual decisions on returning. In particular, we test whether experience and earnings in previous sessions together with demographic variables explain the decision to return to the laboratory. We nd that males and (in monetary terms) well-performing subjects are more likely to participate again in experiments.demographic characteristics, experiments, subject pool

Direct and indirect effects of pathological gambling on risk attitudes

We study individual decision making in a lottery-choice task performed by three different populations: gamblers under psychological treatment ("addicts"), gamblers’ spouses ("victims"), and people who are neither gamblers or gamblers’ spouses ("normals"). We find that addicts are willing to take less risk than normals, but the difference is smaller as a gambler’s time under treatment increases. The large majority of victims report themselves unwilling to take any risk at all. However, addicts in the first year of treatment react more than other addicts to the different values of the risk-return parameter

Matching Markets with Mixed Ownership: The Case for A Real-life Assignment Mechanism

We consider a common indivisible good allocation problem in which agents have both social and private endowments. Popular applications include student assignment to on-campus housing, kidney exchange, and particular school choice problems. In a series of experiments Chen and Sönmez (American Economic Review 92: 1669-1686, 2002) have shown that a popular mechanism from recent theory, the Top Trading Cycles (TTC) mechanism, induces a signi…cantly higher participation rate by agents with private endowments and leads to significantly more efficient outcomes than the most commonly used real-life mechanism, the Random Serial Dictatorship with Squatting Rights