Dillenbourg, P. and Traum, D. (1996). Grounding in computer-supported collaborative problem solving. Report of project 11-40711.94, TECFA, University of Genèva. Available from: http://tecfa.unige.ch/tecfa/research/cscps/bootnap.html.
This report contain the analysis of the ‘bootnap’ project. The authors used a MOO environment for enquirying multi-modalities forms of communication to observe grounding in computer-mediated communication. They asked some pairs to play a mistery solving game and they record their interaction on the textual chat, on the whiteboard and through virtual actions (i.e., move to go from a rome to the other).
Their observations indicated a relationship between grounding and problem solving. In particular they connected the acknoledgement rate to the problem solving variables (e.g., low acknowledgment rates are associated with long-term cross redundancy) than to other dialogue variables.
Controversely, they started looking at cross modalities acknowlegments even if they say that the system they used was not specifically designed to support such cross-modalities acknowledgments. However, they do notice the fact that action can generally be interpreted as acknowledging something if it is prodiced very briefly after. Unfortunately, they could not get too much in details in that because the number of the examples of such situations was too low for drawing any conclusions.