We conducted the first randomized controlled field experiment of an Internet reputation mechanism. A high-reputation, established eBay dealer sold matched pairs of lots— batches of vintage postcards—under his regular identity and under new seller identities (also operated by him). As predicted, the established identity fared better. The difference in buyers’ willingness-to-pay was 8.1% of the selling price. A subsidiary experiment followed the same format, but compared sales by relatively new sellers with and without negative feedback. Surprisingly, one or two negative feedbacks for our new sellers did not affect buyers’ willingness-to-pay.

This paper contributes to the ongoing methodological debate on context-free versus in-context presentation of experimental tasks. We report an experiment using the paradigm of a bribery experiment. In one condition, the task is presented in a typical bribery context, the other one uses abstract wording. Though the underlying context is heavily loaded with negative ethical preconceptions, we do not find significant differences with our 18 independent observations per treatment. We conjecture that the experimental design transmits the essential features of a bribery situation already with neutral framing, such that the presentation does not add substantially to subjects’ interpretation of the task.

This paper investigates the development of conventions of trust in what we call intergenerational games, i.e., games played by a sequence of non-overplapping agents, who pass on advice on how to play the game across adjacent generations of players. Using the trust game of Berg et al. (1995) as our experimental decision problem, advice seems to decrease the amount of trust that evolves when this game in played in an inter-generational manner in that it decreases the amount of money sent from Senders to Returners. Ironically, advice increases trustworthiness in that Returners tend to send more back. Further, subjects appear to follows conventions of reciprocity in that they tend to Send more if they think the Returners acted in a “kind” manner, where kind means the Sender sent more money than the receiver expected. Finally, while we find a causal relationship running from trustworthiness to trust, the opposite can not be established. We note that many of our results can only be achieved using the tools offered by inter-generational games. The inter-generational advice offered provides information not available when games are played in their static form. Combining that information with elicited beliefs of the Senders and Returners adds even more information that can be used to investigate the motives that subjects have for doing what they do.

We study a class of trust-based cooperation dilemmas that evolve in continuous time. Characteristic of these dilemmas is that as long as all n players continue to cooperate, their payoffs increase monotonically over time. Simultaneously, the temptation to defect increases too, as the first player to defect terminates the interaction and receives the present value of the payoff function whereas each of the other n — 1 players only receives a proportion δ (0 < δ < 1) of the defecting player's payoff. We introduce a novel experimental institution that we call the Real-Time Trust Game (RTTG) to examine this class of interactions. We then report the results from an iterated RTTG in which the values of n and δ are varied in a between-subjects design. In all conditions, cooperation breaks down in the population over iterations of the game. The rate of breakdown sharply increases as n increases and more slowly decreases as δ increases.