Coordination des communautés de pratique : les rôles différenciés de la Réputation et de la Confiance.

In the frame of a knowledge based economy, a growing part of the processes of knowledge production and knowledge diffusion are hold by so-called communities of practice. Communities, by providing intangible spaces triggering the sharing of information and knowledge, play a paramount role in collective learning processes. Those communities may be broadly defined as specific social interaction structures aiming at the production and the diffusion of knowledge. More precisely, they correspond to groups of people engaged in a common practice and frequently interacting in order to develop their competences. Due to the absence of any contractual scheme, one of the defining traits of communities of practice lies in the ability of the members to determine their specialization trajectories in a decentralized manner. To put it differently, they enjoy the ability to determine the extent and the nature of their contribution to the growth of the common practice. However, such a freedom left to the agents may raise some issues concerning the efficiency of this system. From the incentives point of view, the absence of any contractual scheme may give the agents the opportunity to engage in opportunistic behaviors, giving rise to a problem of prisoner dilemma. Moreover, the absence of any clear-cut division of labour may imply two possibilities: either the agents engage in too different tasks which may hinder the overall coherence of the common practice. Or the individuals engage in similar activities, leading to problems of redundancies in the common practice. The goal of this thesis is to isolate some of the mechanisms governing the coordination of agents within communities of practice. It is proposed that coordination is supported by the emergence of individuals enjoying a specific status within the community: communitarian leaders. Leadership is here defined as the ability to influence individual behaviors through an influence exercises on information and knowledge flows. This is due to the adoption by community leaders of a central position within the community. The leaders’ ability to control knowledge flows arises out of the conjunction of two complementary features. First, the ability to constrain communication flows, which arises out of their ability to take on the role of mediators and to link distant parts of the community. This ability allows leaders to enhance the coherence of the common knowledge base by filtering communication flows. Second, due to their ability to accumulate relationships with other members of the community, leaders enjoy an enhanced access to information and knowledge. Knowing this, community members assume that leaders are facing lower levels of uncertainty, implying that they are able to take more adequate decisions. Community leaders are likely to be subject to mimesis behaviors. Leadership constitutes an emergent phenomenon in the sense that it arises out of a process of selforganization. The conjunction of reputation and trust comes in support of the community leaders’ specific status. Reputation is here defined as a set of information concerning constant and recurring evidences of an individual’s past behavior. Those information are shared among community members. Reputation, by reducing the uncertainty associated with an individual’s behaviour during a first interaction, eases its occurrence. Individuals endowed with high reputation levels benefit from a higher number of acquaintances within the community. This allows them to acquire a central position in the community. Trust complements reputation in the frame of recurrent interactions among two partners. Trust corresponds to the expectation of a cooperative behavior and relies on the accumulation of knowledge arising out of preceding interactions. A strong relationship binds reputation and trust: while reputation constitutes a necessary condition for a first interaction to occur, trust allows perpetuating it