Fairness is a strong concern as shown by dictator and ultimatum experiments. Efficiency, measured by the sum of individual payoffs, is a potentially competing concern in games such as the prisoners' dilemma. In our experiment participants can increase efficiency by gift giving. In the one-sided...

Many bidders in eBay employ bidding strategies that involve late bids, incremental bids, or both. Based on field evidence, we discuss teh manner in which late bids are caused both by sophisticated, strategic reasoning and by irrationality and inexperience, the interaction of late bidding and...

Auctions on the Internet provide a new source of data on how bidding is influenced by the detailed rules of the auction. Here we study the second-price auction run by eBay and Amazon, in which a bidder submits a reservation price, and has this (maximum) price used to bid for him by proxy.[...]

Several current social utility models posit fairness as a motive for certain types of strategic behavior. The models differ sharply with respect to how fairness is measured. Distribution models measure fairness in terms of relative payoff comparisons. Reciprocal-kindness models measure fairness...

Trust that suppliers and buyers will keep their word is a necessary ingredient to a wellfunctioning marketplace. Nowhere is the issue trickier than for electronic markets, wheretransactions tend to be geographically diffuse and anonymous, putting them out of the reach ofthe legal safeguards and...

Online reputation -"feedback"- mechanism aim to mitigate the moral hazard problem associated with spatially distant exchange among strangers by providing traders with the type of information available in small groups, where members are frequently involved in another's dealings. We compare...

We examine how communication affects cooperation with the help of seven standard public goods experiments that only differ with respect to the medium of pre-play communication. Our treatments include bi-directional and unidirectional communication via (mostly electronic) auditory and/or visual...

Experimental sealed bid first price auctions with private values in which feedback onthe losing bids is provided yield lower revenues than auctions where this feedback isnot given. Furthermore, bids tend to be above the equilibrium predictions for riskneutral bidders. While the latter...

The internet facilitates interactive and asynchronous communication among human and artificial agents in large bilateral markets. As a consequence, new institutional structures are emerging in the new economy. I discuss a few core problems associated with the economic design of internet markets...

We report on a research program that employs the indirect evolutionary approach to analyze how the institutional environment drive the evolution of trust and trustworthiness through the evolution of moral preferences, and how in turn the evolution of preferences shapes the evolution of the...