In this paper, we propose a novel approach to the assessment of the emergent socio-cognitive roles learners adopted during peer interactions. The approach posits that different dimensions of peer interaction emerging from temporal-semantic discourse information and the structure of interactions can be used to diagnostically reveal the emergent roles of learners during peer interactions. As such, the combination of two established methodologies, Group Communication Analysis (GCA) that centers on temporal semantic properties of online discourse with Social Network Analysis (SNA) that reflects structural interpersonal patterns of online interactions are used to gain a deeper understanding of the emergent, socio-cognitive roles learners adopt during peer interactions at scale. The proposed approach is named socio-cognitive group communication and interpersonal position (SCIP) analysis and is defined as a combination of these two distinct and complementary analytic techniques. The proposed SCIP approach is examined on data produced during peer interaction in a massive open online course (MOOC) delivered via Coursera. Using SCIP analysis, learner activity is described through five roles: Lurkers, Followers, Socially Detached, Influential Actors and Hyper Posters. We conclude the paper with a detailed discussion of the theoretical, methodological, and practical implications for peer interaction research. The scalability of the methodology opens the door for future research efforts directed towards understanding and improving peer-interactions at scale.