Strong and weak ties are compared in terms of their contributions to information flow about the work activity of persons in intraorganizational social networks. Strong ties are more important than weak ties in promoting information flow about activities within an organizational subsystem. Weak ties are more important than strong ties in promoting information flow about activities outside an organizational subsystem. The strength of weak ties in promoting boundary-spanning information flows lies not in their individual efficiency but in their numbers. In general, production of the highest probabilities of information flow is associated with a combination of both weak and strong ties. © 1982.

Investigators interested in developing a general theory of social cohesion are confronted, with a complex body of work that involves various definitions of social cohesion, specialized literatures on particular dimensions of social cohesion (e.g., membership turnover, organizational commitment, categorical identifications, interpersonal attachments, network structures), and lines of inquiry focused on the social cohesion of specific types of groups (e.g., families, schools, military units, and sports teams). This review addresses the problem of integrating the individual and group levels at which social cohesion has been defined. It also develops a perspective on social cohesion as a domain of causally interrelated phenomena concerned with individuals' membership attitudes and behaviors, in which the major dimensions of social cohesion occupy different theoretical positions with respect to one another as antecedent, intervening, or outcome variables.

I extend the theoretical domain of sociology into an area of social psychology that therefore has been the exclusive domain of psychologists. Specifically, I develop a social structural perspective on the choice shifts that individuals make within groups. During interpersonal discussions of issues, choice shifts occur when there is a difference between group members' mean final opinion and their mean initial opinion. Explanations of choice shifts have emphasized group-level conditions (e.g., a norm, a decision rule, a pool of persuasive arguments, a distribution of initial opinions). I argue that choice shifts are a ubiquitous product of the inequalities of interpersonal influence that emerge during discussions of issues. Hence, I bring choice shifts squarely into the domain of a structural social psychology that attends to the composition of networks of interpersonal influence and into broader sociological perspectives concerned with the formation of status structures.

Investigations of small world contact networks, defined as networks with a short characteristic path length and a substantial local clustering of contacts in the neighborhood of each node, have emphasized the process performance of such networks. The argument that large-scale, small world, contact networks are structures with startlingly efficient process performance is premised on the existence of shortcuts, without which the characteristic path lengths of the networks would be substantially larger. No doubt, given a high probability of transmission in each contact of a network, such shortcuts are a potential structural basis of reliable flows of information, influence, material and disease. However, interpersonal contacts are often markedly unreliable transmission conduits, and the average shortcut contact may be a more unreliable, episodic, transmission conduit than the average contact of cliques. With markedly unreliable contacts, fundamental helix substructures, that are parallel-transmission subsystems of the contact network, importantly enter into the analysis of network performance. These substructures of disjoint path redundancies are based on the local clustering of contacts in the neighborhoods of each node. Drawing on network reliability theory, this article presents an approach in which intersecting cliques of contact networks are a theoretically important construct in the specification of the transmission implications of observed contact networks. Clique intersections are a structural basis of path redundancies that enable reliable transmission among the nodes of contact networks consisting of contacts that may or may not be active conduits of transmissions during some period of time. The strong contacts that occur among clique members further enhance the contributions of these path redundancies. © 2010 Elsevier B.V.

The assumption that individual behavior has an antecedent evaluative foundation is an important component of theories in sociology, psychology, political science, and economics. In its simplest form, the antecedent evaluation is a positive or negative attitude toward an object that may affect an individual's object-related behavior. This attitude may be influenced by the attitudes of other persons. The occurrence of such endogenous interpersonal influences, in which persons' attitudes are affected by other persons' attitudes, is among the basic postulates of social psychology. The present article advances work on the attitude-behavior linkage in behavioral cascades by jointly considering two theories: the theory of reasoned-planned action, which emphasizes the deliberative foundations of individuals' object-related behaviors, and social influence network theory, which emphasizes the group dynamics involved in the formation of individuals' attitudes. © American Sociological Association 2010.

The density of ingroup relations continues to be proposed as an indicator of structural cohesion. Network density is obviously a misleading indicator of structural cohesion when a group has subgroups; in such circumstances, the cohesion may be entirely internal to the subgroups. However, it is plausible that network density is a useful indicator of structural cohesion when it can be assumed that a group lacks subgroups. In order to analyze this possibility, I construct a set of random networks, increase the density of relations in these networks, and observe how the networks' structure develops in terms of five measures. The results show that low densities in large networks may be associated with more structural cohesion than higher densities in smaller networks; it is suggested that in field studies, attempts to control for network size will encounter problems of nonlinearity and heteroscedasticity. I conclude that network density is not a useful indicator of structure and that direct measurement of structure is to be preferred. © 1981.