Impact of group size on spatial structure understanding tasks

Co-located collaborative tasks allow teams to leverage the skills of each individual member. While numerous guidelines exist to develop visualizations for individuals working on desktops, very little is known about how groups of individuals interpret and comprehend diverse types of visual constructs on larger displays. To study whether group size impacts the collective understanding of relationships in three-dimensional (3D) spatial structures when using different types of presentation, we carried out three experiments. We compared individual performance at structure understanding tasks to performance of groups containing two or four members. We consider two alternate visualization techniques for extracting 3D structure information: a 3D view with animated rotations and a combination of one static 3D plus three static two-dimensional (2D) projection views. In general our studies suggest that as group size increases, so does accuracy but with a cost in efficiency. Our results also suggest that beyond a threshold limit in group size, performance on certain tasks begins to degrade. Regardless of group size, participants performed better when the display was presented in the animation condition instead of the multiple static views, except when large groups needed to relate the visualization to a physical counterpart. We summarize our results in terms of Steiner's model for explaining the effects of group size and task characteristics on group performance.