We study behavior within a simple principal-agent experiment. Our design allows for a large class of linear contracts. Principals can offer any feasible combination of (negative) fixed wages and incentives in the form of return sharing. This great contractual flexibility allows us to study incentive compatibility simultaneously with issues of ‘fair sharing’ and reciprocity, which were previously found to be important. We find a high degree of incentive-compatible behavior, but also ‘fair sharing’ and reciprocity. In contrast to other incentive devices studied in the literature, the incentives are ‘reciprocity-compatible’. Principals recognize the agency problem and react accordingly.

This study uses an experimental approach to examine whether markets are sensitive to the internal incentive structure of the competitors. Toward this goal, we modeled the competitors in a price competition duopoly game as three-player teams. Each player simultaneously declares a bid (price) and the team whose total bid was lower won the competition and was paid accordingly. The losing team was paid nothing, and in case of a tie, each team was paid half its price. This duopoly game was studied under two conditions; a cooperative treatment in which the team's profit was divided equally amongst its members and a non-cooperative one in which each individual member was paid her own bid. Whereas the Nash equilibrium is for each player in either treatment to demand the minimal price possible, we predicted that convergence to the competitive price would be much faster in the cooperative treatment than in the non-cooperative one. The experimental results firmly confirmed this prediction.

This paper studies how subjects in a three-person sequential step-level public good game learn to punish free riders more over time. Our current work makes several additions to the literature on other regarding behavior. First, our experiment provides evidence that subjects care about the actions that lead to an outcome as well as the outcome itself, replicating the results of A. Falk, E. Fehr and U. Fischbacher (Economic Inquiry, in press), J. Brandts and C. Sola (Games and Economic Behavior, 36(2), 138-157, 2001.) and J.H. Kagel and K. Wolfe (Working paper, Ohio State University, 1999). Second, our experiment provides one of the first tests of the newer theories of reciprocity by A. Falk and U. Fischbacher (Working paper, University of Zurich, 2000) and G. Charness and M. Rabin (Quarterly Journal of Economics, in press) that take a psychological games approach. We find that these theories fail to explain the experimental data. Finally, we examine the mechanism by which subjects learn to punish free-riding more ofter over time.

In this paper we examine how risk attitudes change with age. We present participants from age 5 to 64 with choices between simple gambles and the expected value of the gambles. The gambles are over both gains and losses, and vary in the probability of the non-zero payoff. Surprisingly, we find that many participants are risk seeking when faced with high-probability prospects over gains and risk averse when faced with small-probability prospects. Over losses we find the exact opposite. Children's choices are consistent with the underweighting of low-probability events and the overweighting of high-probability ones. This tendency diminishes with age, and on average adults appear to use the objective probability when evaluating risky prospects.