The use of reputation and gossip in small cooperative group activities

This paper describes an investigation of the influence of different types of information sources on the ability of self-interested agents to select good partners in small dynamic environments and to be selected by others. Reputation systems are helpful in small groups for agents needing to identify good partners, if the active agent population is dynamic. In such cases, a reputation system provides an experience-keeping mechanism, in addition to its traditional role as an information centralizer. However, the availability of additional information is not always beneficial to self-interested agents. In particular, by accelerating the convergence to the "most generous" agents available, it decreases outcomes for less generous agents. (Whether this is a good feature or not depends on one's perspective.) The theoretical analysis as well as these experimental results are consistent for several different parameter sets of the environment and agent mixtures. The paper also defines a new performance measurement mechanism, one which enables evaluation of the impact information sources have on an existing system and comparison across different environmental settings.