Group and dyadic communication in trust games

We study the behavioral consequences of interpersonal communication prior to experimental Trust games. We manipulated the richness of the communication medium and the size of the communicating group. Communication richness failed to produce significant differences in first-mover investments, but the size of the communicating group did: The amounts sent were significantly higher in the dyadic communication conditions than in the group communication and no-communication conditions. We also found that first-movers' expectations of secondmovers' reciprocation strongly predicted their levels of investment.