Knowledge construction can be facilitated through different types of social interactive environment. A knowledge network environment (KN) develops a knowledge-centered network visualizing the structure of collective knowledge. A social network environment (SN) creates a people-centered network visualizing the social relationships among people. Considering the connectedness of knowledge and people, this study moves the conversation forward by introducing an integrated environment of both knowledge- and people-centered network, a social knowledge network environment (SKN). The study aimed at comparing the three types of environments and investigated their effect on collaborative knowledge construction processes and individual learning outcomes. The quasi-experiment results indicated that these three environments differed in their effects on learners' knowledge construction levels, the sequential patterns, as well as individual learning outcomes. Learners in SN had a highest rate of social interaction than the learners in the other environments. KN learners had a higher rate of allocentric elaboration than SN learners. SKN learners showed a higher level of surface and elaborative application, reflection, and knowledge construction outcomes than KN and SN learners. The different roles of social interactions were further discussed across three environments.