Collaborative learning environments in undergraduate introductory physics courses, such as those promoted by University Modeling Instruction (UMI), influence both student performance and behavioral constructs. Of these constructs, self-efficacy has the power to predict student performance and persistence in the major. Our study examines a plausible mechanism by which self-efficacy may be influenced in these collaborative courses, particularly as it relates to two sources of self-efficacy: vicarious learning and verbal persuasion. We found that social network analysis-based centrality measures are positively correlated with self-efficacy scores on the Sources of Self-Efficacy in Science Courses--Physics (SOSESC-P) for students in either traditional lecture or UMI introductory physics courses. Moreover, centrality scores--calculated as either degree centrality or undirected PageRank centrality--correlate positively with scores on the vicarious learning and verbal persuasion subsection of the SOSESC-P. This suggests that collaborative, inquiry-based learning environments may promote higher student self-efficacy.