Published online 15 January 2010. By the proliferation of online courses, the social dimension of computer supported collaborative learning (CSCL) is becoming more important than before. Research shows that communicative behavior adaptation to the computer medium is a critical issue in CSCL social relationship development. Two dominant theories in the CSCL field, social information processing theory and adaptive structuration theory, argue that individuals do not simply receive the technology passively but they adapt their behavior to increase benefits from the technology. This paper develops an instrument in order to operationalize the notion of individual’s communicative behavior adaptability in CSCL. Through an exploratory factor analysis performed on a small sample of post graduate students of an online degree in an Australian university, three factors have been unveiled: (1) individual perception of self-representation, (2) individual perception of compatibility, and (3) individual perception of the use of computer technology. Identification of these factors is expected to facilitate understanding of individuals’ social behaviors in CSCL environment, which in turn will guide the design of CSCL systems. In addition, the paper examines the relationships between the extracted factors and four environmental factors: learner’s characteristics, course characteristics, instructor characteristics, and technology characteristics. The results show that none of these characteristics strongly affect perception of self-representation or perception of the use of computer technology. On the other hand, a strong relationship was found between perception of compatibility and learner’s and course characteristics. The reliability as well as validity of the study is examined and findings are discussed. These findings will provide further insights into the design process of CSCL systems.