Most asynchronous computer-supported collaborative learning (CSCL) environments can be characterized as "functional" environments because they focus on functional, task-specific support, often disregarding explicit support for the social (emotional) aspects of learning in groups which are acknowledged by many educational researchers to be essential for effective collaborative learning. In contrast, "sociable" CSCL environments emphasize the social (emotional) aspects of group learning. We define sociability as the extent to which a CSCL environment is perceived to be able to facilitate the emergence of a sound social space with attributes as trust and belonging, a strong sense of community, and good working relationships. Specific environmental characteristics, which we have designated social affordances, determine sociability. This explorative study deals with the construction and preliminary validation of a self-reporting (Dutch language) Sociability Scale for determining the perceived degree of sociability of CSCL environments. It is one-dimensional Scale consisting of 10 items and has an internal consistency of 0.92. It was further validated on the basis of a well-developed nomological network. The results of the explorative study are promising and show that the sociability scale has the potential to be useful as a measure for perceived sociability.