In a study of 1986, Miyake claims that in a collaborative activity we observe a spontaneous distribution of roles between the one who does (task-doer) and the one who observes (observer). In a CSCL case, the typical configuration of the computer reinforces, if not imposes, this distribution of roles. Actually, as only one learner at a time can access to the activity through the mouse, the other learner becomes obligatory an observer and he has to resign in looking and sometimes to criticize what the other does. MIYAKE, N. (1986). Constructive interaction and the iterative process of understanding. Cognitive Science, 10, 151-177.