The Effects of View Portals on Performance and Awareness in Co-Located Tabletop Groupware

Tabletop work surfaces have natural advantages for co-located collaboration, but also have physical constraints that can make group work difficult. View portals have been proposed as a way to provide access to other parts of a table surface, and as a way to re-orient content for group members in different locations; however, there is little research on whether portals really do improve group performance, how much they help, and whether they change other aspects of collaboration. We report on two studies that evaluate the effects of portals on group performance and behavior. Our first study showed significant performance advantages for portals: people were able to complete tasks more quickly and with more equal division of labor. Our second study, with a realistic design task, showed that people used portals extensively and saw them as valuable, but that they affected people's ability to maintain awareness, coordinate access to objects, and understand the organization of the workspace. Our work demonstrates benefits and potential drawbacks of portals for tables, and suggests that designers should carefully consider both individual and group needs before implementing these and other tabletop view augmentations.