This study attempts to make inferences about the mechanisms that drive network change over time. It adopts simulation investigation for empirical network analysis to examine the patterns and evolution of relationships formed in the context of a massive open online course (MOOC) discussion forum. Four network effects--"homophily," "reciprocity," "transitivity," and "preferential" attachment--were tested to explain the dynamic mechanisms of interaction in the MOOC forum. Understanding the network dynamics of relationships will allow us to explore how to develop a robust peer-supported learning environment and in turn improve the online learning experience in MOOCs. [