  As educators we often ask our physics students to work in groups---on
tutorials, during in-class discussions, and on homework, projects, or exams.
Researchers have documented the benefits of group work for students' conceptual
mastery and problem solving skills, and have worked to optimize the
productivity of group work by assigning roles and composing groups based on
performance levels or gender. However, it is less common for us as a physics
education research community to attend to the social dynamics and interactions
among students within a collaborative setting, or to address students' views
about group work. In this paper, we define \textit{epistemic stances toward
group work}: stances towards what it means to generate and apply knowledge in a
group. Through a case study analysis of a collaborative problem solving session
among four physics students, we investigate how epistemic stances toward group
work interact with social dynamics. We find that misalignment of stances
between students can inform, and be informed by, the social positioning of
group members. Understanding these fine-grained interactions is one way to
begin to understand how to support students in engaging in productive and
equitable group work.
