I've found notes I've written when attending a talk by my phD director. I put it here since it could be seen as a framework for my phD. 1. Communication tools fulfill cognitive fonctions :

- Group memory : a chat, for instance, keep an history of the conversations, the questions asked... An email is a also a part of a cognitive system and not only a link between two persons. A whiteboard enable participants to have a joint understanding of the problem. The wire can play a role in solving the problem. For instance, in a chat you can scroll back to read the questions asked by the participants and answers to them sequentially (wheras in oral conversation, one cannot say "yes, no, yes) to three questions asked by three different adressees. - Storing the context : masters thesis Ott, 1999 - Group mirrors : ArgueGraph : when one give a group a picture of itself, it triggers reactions. Jermann; Donath. - Awareness tools : mutual modelling - Interaction analysis 

2. Distributed cognitive systems : the group members and the tools constitutes ONE cognitive systems : shared memory, shared cognitive load, ... group metacognition.

3. Mediated communication is a substance : people interact with each other and we can do something with it.

4. Learning science needs computer science. Our approach : model/hypotheses + design/build + test/analyze (empirical studies)