In the field of I/O psychology, most of studies estimate that team performance under temporal pressure is directly related to shared understanding (SU) within a team. In order to account for the dynamics of SU within a team, we have studied the evolution of contents, forms and mechanisms of the sharing process, as a function of context variability and temporal pressure. We primarily work in line with the Team Situation Awareness model, that is usually mobilized in work situations. A first study allowed us to identify the various elements of SU and its dynamics in feminine handball competitions. The analysis permitted to identify (a) four typical forms of shared understanding, (b) seven typical contents shared and (c) six typical interaction processes between teammates. Results shows that sharing forms are local and punctual, alternating between two main modes of SU : either a preestablished plan follow-up, together with possible adaptation to conclude a given action, or a real-time adaptation to the context of action. A second study deals with improvisational theatre, regulated in real time by the director through earphones. Our results show that the sharing typical forms, contents and processes that rise in this activity also correspond to the classification we made in the first field study, which strengthens the genericity of our proposal. These results invite us to think that online regulation may either enhance or hamper the SU and thus the collective performance, respectively by improving the update and interaction processes between actors, or by overloading the cognitive activity of the team members in the course of action. Based on these results, we propose to consider the SU as a process that works over two space and time scales: on the global scale, SU may envolve over long periods within a team; and on a local scale, SU is actually developed through interpersonal updating and in situ adjustment processes. In order to account for these two scales, we proposed a team coordination model together with an interindividual regulation model. Our work opens the way to the study of the correlation between local mechanisms of shared understanding and the global dynamics of a collaborative activity.
