## 2 Related Work
### Collaborators' Position Arrangements  
In the physical world, spatial relationships and the positioning of people in close proximity can significantly influence their performance and behavior during collaboration [15]. That is, different relative physical orientations afford different types of collaborative styles and user experiences when working together (e.g., competition vs. collaboration) [52; 53]. Whether the same applies to VR environments is not clear because there is not much research that has looked at this in detail. For social spaces in VR, it is a key factor that affects how users will behave when collaborating. F-formations, a social construct that describes the distance and relative body orientation among a group of users, consider the spatial relationships that occur as people arrange themselves during face-to-face interaction for optimal task-dependent communication [15]. In the real world, different body orientations, such as face-to-face, side-by-side, or corner-to-corner, can afford different types of collaboration behaviors and feelings: competitive, collaborative, or communicative. Similar to human-to-human interaction, it is important for immersive collaborative systems to investigate whether avatar-to-avatar, or virtual proxemics relationships, can also result in different collaborative experiences and performances, and what these are.  
Much research has explored how users worked together under different collaborative couplings in other platforms, such as tabletops [16; 54] and displays [55; 56]. When wearing VR HMDs, users are immersed in the environment and, as such, the only way to perceive other collaborators is via their avatars. In the CALVIN VR system [49], users can see the avatar of their partners, including positions and orientations, but it is difficult for them to perceive what their partner is viewing and their actions. [PERSON] et al. [57] proposed the IIVC model that enables developers to embed the users' physical environment into the virtual environment and can make a user aware of the physical limitations of their partners. Despite this research, whether avatar positioning has an effect on users' tasks and their perception of them is an aspect that has not been studied in great detail, especially in the context of exploring visualizations in learning scenarios.  
Our research seeks to increase the understanding of whether proxemics relationships and arrangements that occur in the physical world also apply to 3D virtual worlds and what effect they have on users' task performance and learning. We want to draw implications for how we can design collaborative VR tools that deal with visualizations of nontrivial concepts for learning, sense-making, and data analysis.  
In short, collaboration brings many benefits to exploratory and sense-making activities with interactive visualizations. Research on collaborative visualizations has mainly focused on the use of large displays (such as interactive tabletops and situated displays), small screen displays (such as mobile phones and tablets), and desktop displays. However, VR is still largely an emerging but fast-growing technology that is changing how we can interact with virtual objects and environments. To the best of our knowledge, there has not been any research looking at collaborative visualizations in VR learning environments. This research aims to fill this gap and expand our understanding of how collaborative activities with visualizations can take place within VR. Therefore, we extend the prior work with a comprehensive experiment with a collaborative visualization VR tool to explore issues of public and private workspaces, control and view sharing, and social space arrangement.