In this study, we investigated the effect of type of positive interdependence (roles, rewards, roles-plus-rewards, or no structure) and affiliation motives (high vs. low) in an asynchronous, collaborative learning environment. College reentry students worked together in small, fully online discussion groups that lasted for seven days. Results indicated that participants in groups given roles plus rewards interacted with their teammates significantly more than those given rewards only or no-structured-interdependence conditions. A significant positive correlation suggested that participants with higher numbers of interactions attained higher posttest scores. However, no significant differences were found in achievement by type of interdependence or by affiliation motive. Results also revealed that type of interdependence and affiliation motive had a significant impact on student attitudes. Implications for integrating small group work in online higher education settings are discussed.