Abstract

University of Pennsylvania, USA, el322{at}nyu.edu ' + u + '@' + d + ' '//--> One of the most consistent findings in experimental studies of social dilemmas is the positive influence of face-to-face communication on cooperation. The face-to-face `communication effect' has been recently explained in terms of a `focus theory of norms': successful communication focuses agents on pro-social norms, and induces preferences and expectations conducive to cooperation. 1 Many of the studies that point to a communication effect, however, do not further explore whether and to what extent the communication medium affects cooperative behavior. In this article, we ask if pro-social behavior can emerge and survive in computer-mediated environments. We show that, like face-to-face communication, computer-mediated communication also positively affects cooperation in social dilemmas, but cooperation is more difficult to establish and maintain. We argue that the discrepancy between the computer-mediated and the face-to-face communication effects is a consequence of the distinct capabilities of different media to focus agents on pro-social norms and to allow them to develop mutual expectations about future behavior. Key Words: social dilemmas • laboratory experiments • communication • social norms • cooperation • computer-mediated communication.