Drawing on two recent theories, this article proposes interaction hypotheses involving the joint effects ojsalient pup versus individual identity and long-term versus short-term group membership on the social, interpersonal, and intellectual responses ojpup members collabo- rating via computer-mediated communication. Participantsfimn institutions in two countries used computer-mediated communication under various conditions. Results indicate that some conditions oj computer-mediated communication use by geographically dispersed partners render effects systematically superior to those obtained in other mediated conditions and greater or lesser than effects obtained thmughface-to-face interaction.