Heiser, J., Tversky, B. and Silverman, M. (2004). Sketches for and from collaboration. In J. S. Gero, B. Tversky, and T. Knight (Editors). Visual and spatial reasoning in design III. Pp. 69-78. Sydney: Key Centre for Design Research [pdf]
This paper report an interesting experimental study on how people might use a visualization to solve a collaborative task. The authors sketch a couple of important points about diagrams: sketches maintain an active focus on the task; pointing over the diagram assured a visual grounding on the part of the map being discussed; the use of the pointers of the map discharged cognitively the task. The experimental study confirmed that the possibility to face the task facte-to-face on the same map increased drammatically the performances of dyads over remote dyads.
Two interesting pointers in the paper: the uathors used other participants to evaluate the aesthetic effectiveness of the maps produced in the experiment; finally the authors pointed out that even if the task was a spatial one the findings seems to be applicable also to non spatial tasks.