Contenu du sommaire : Analyses de réseaux et structures relationnelles. Etudes réunies et présentées par Emmanuel Lazega

Ronald S. Burt : Social capital, structural holes and the entrepreneur. This paper is an introduction to social capital effects at the top of the firm. I contrast social capital with human capital, and discuss the information and control benefits provided by contact networks rich in structural holes. Higher returns to human capital are expected for people rich in social capital. I use network data on a probability sample of senior managers to illustrate two conclusions : (1) Social capital matters for the relative success of managers. (2) Social capital matters more where individuals matter more. Where many people do the same kind of work, peers are a frame of reference, and legitimacy is established by the number of people doing the work. Where few people do the same kind of work, there is no frame of reference, and legitimacy has to be established. The information and control benefits of structural holes are more valuable for the second kind of work. Results on the senior managers show that social capital is more valuable toward the top of the firm, and more valuable for managers in unique jobs than for managers with many peers. In fact, the value of social capital decreases exponentially with the number of managers doing the same work.

Beate Völker, Henk Flap : Friendship and enmity under state communism. The case of East Germany. People's personal networks are conditioned by the institutions of the society they live in. Communist rule not only accounts for the emergence of a specific type of friendship but also for the growth of suspicion and enmity in one's personal relations. Friendship is provided by someone's partner, 'best friends', and close family, who together form a 'niche' that protects against the adverse consequences of the political control by the regime. The organized dependency on the party for nearly all opportunities accounts for enmity against those with whom one would not voluntarily interact, but who come as part of a network package, like relations to persons at work or in the neighborhood. In a case study of the GDR it is shown that the citizen's friends and foes are rather similar to the citizen self with regard to education and occupation. This association between institutions and networks can be understood by interpreting social interaction as investments in social capital.

Mark S. Mizruchi, Shin-??? Han, Gwendolyn A. Dordick : Bank loans and corporate board representation. The relation between resource flows and interorganizational networks. Examination of resource exchanges between individual firms is often essential to test theories of interorganizational networks. Using previously unavailable data on bank loans to U.S. nonfinancial corporations from 1938 through 1941, this paper examines for the first time with U.S. data the relation between bank loans and board representation. Although most nonfinancial corporations have bank officers on their boards, fewer than half of these ties represent lending banks. Drawing on the resource dependence perspective, political sociology, and agency theory, we develop a model to predict the conditions under which the bankers on a firm's board represent the firm's lenders. Loans are most likely to be accompanied by board representation when the amounts are large and the firm's profits are low. This suggests that board representation is a means employed by banks to monitor their loans under high-risk conditions.

Nan Lin : Social resources : a theory of social capital. The present paper reviews the theory of social resources as sociological theory intended to describe individual actions in the context of social structure. Social resources defined as resources embedded in social ties accessible in the social networks are seen as useful as personal resources which individuals possess. By accessing and using social resources, individuals may attain instrumental or expressive goals of action. However, the matching of action intentions and interaction patterns may require either positional advantages and/or choices in action. Thus the theory of social resources consists of three propositions : (1) that social resources facilitate goal attainment (the social resources proposition), (2) that original social positions facilitate access to and use of social resources (the strength of position proposition), and (3) that choice of weaker and heterophilous ties facilitates access to and use of social resources (the strength of tie proposition). The paper presents further directions for theoretical elaborations, and comments on its linkage to the notion of social capital.

Harrison C. White : Network switches, actors and domination grammar. Distinct networks are social realizations, in types of tie, of different cultural realms as cross-sectional snapshots of some locale of action. I build here a view of socio-cultural process as switches between types of networks, with actors of all scopes being shaped as byproducts. Discourse both comes from and engenders structures of domination within such process, yielding grammar as a trace.

Franz Urban Pappi, Thomas König : Peak organizations in policy-domain networks : the German and American labor policy domain compared. A policy domain network is defined as a communication structure between the actors of a policy domain. Confirmed policy networks are measured for the labor policy domain under the Reagan Administration in the U.S.A. and for the first Kohl Governments up to the year 1988 for West Germany. Using this data on ties among more than a hundred corporate actors in each country, the role of peak organizations is conceptualized as a broker organization for its member organizations. Based on the typology of brokers provided by Fernandez and Gould (1994), results show that German peak organizations perform their roles as representatives better than their American counterparts, but this role is counterbalanced to a certain degree by the role of gatekeepers of the political system. The paper is an example of the power of comparative network analysis in answering questions of political sociology that are often only answered at the individual level and not at the structural level. power of comparative network analysis in answering questions of political sociology that are often only answered at the individual level and not at the structural level.

Linton ? Freeman : On the structural form of human social groups : a social network perspective. In 1977, Winship demonstrated that if the social proximities linking a collection of individuals satisfy the properties of an ultrametric, then the social structure giving rise to those proximities is a nested hierarchy in which collections of actors overlap only by containment. Since this structural form corresponds very well to the traditional sociological conception of groups, it is important to assess the degree to which social proximities meet the requirements of an ultrametric. In 1992, Freeman showed that observed data on social proximities do not satisfy these requirements. Despite this failure, he conjectured that proximities in human groups tend toward satisfying the ultrametric requirements. The current paper proposes a stochastic model to address this question. Using the same data sets as the 1992 study, it is shown that the patterning of interaction comes close to the ultrametric form.

Emmanuel Lazega, Marie-Odile Lebeaux : Social capital and lateral constraint. In order to exert power and maintain collective action, it is often necessary to mobilize one's social resources, "one's relations", and to know how to use them. This article examines this mobilization in terms of social capital conversion into lateral social constraints. The analysis is based on sociometric and three-way network data. More precisely, it shows how partners in a collegial organization, a corporate law firm, use leverage (i.e. their connections within the firm) to put pressure on each other. It is shown that actors mobilize their own social capital selectively, depending on the type of tie, the characteristics of the "owner" of the social resources and the relations between those involved. The development of lateral constraints thus appears to be the result of economic calculations, inextricably linked to partners' strategic culture and definitions of identities.