Shared contexts and triadic closure in core discussion networks

This paper inquires into structural explanations for triadic closure in networks of confidants with whom one discusses important personal matters. Building upon the assumption that meeting opportunities affect network characteristics, we primarily argue that the social contexts in which network members meet, substantially affect triadic closure. The main empirical findings are (a) that about sixty percent of the triads in core discussion networks are closed triads, which also means that a substantial part of one's strong relations is unconnected, and (b) that meeting network members in the same social contexts is an important condition for, but certainly does not guarantee triadic closure. Importantly, the specific characteristics of social contexts explain why sharing certain contexts positively affects triadic closure, while sharing other contexts does not.     

Effects of missing data in social networks

We perform sensitivity analyses to assess the impact of missing data on the structural properties of social networks. The social network is conceived of as being generated by a bipartite graph, in which actors are linked together via multiple interaction contexts or affiliations. We discuss three principal missing data mechanisms: network boundary specification (non-inclusion of actors or affiliations), survey non-response, and censoring by vertex degree (fixed choice design), examining their impact on the scientific collaboration network from the Los Alamos E-print Archive as well as random bipartite graphs. The simulation results show that network boundary specification and fixed choice designs can dramatically alter estimates of network-level statistics. The observed clustering and assortativity coefficients are overestimated via omission of affiliations or fixed choice thereof, and underestimated via actor non-response, which results in inflated measurement error. We also find that social networks with multiple interaction contexts may have certain interesting properties due to the presence of overlapping cliques. In particular, assortativity by degree does not necessarily improve network robustness to random omission of nodes as predicted by current theory.     

How stable is the core discussion network?

Researchers have paid increasing attention to the core discussion network, the set of people we turn to when discussing important matters. Because the core discussion network is theorized to be composed of people's closest ties, not fleeting acquaintances, it is expected to be largely stable, evolving slowly over the span of people's lives. However, recent studies have shown that networks are strongly affected by the contexts in which people interact with others, and as people experience life course transitions, they also often enter new contexts – school, college, work, marriage, and retirement. We ask whether, as actors enter new social contexts, the core discussion network remains stable or changes rapidly. Based on original, longitudinal, qualitative and quantitative data on the experience of first-year graduate students in three academic departments in a large university, we examine the stability of the core discussion network over the first 6 and 12 months in this new context. We test four competing hypotheses that focus on strength of ties, new opportunities, obligations, and routine activity and predict, respectively, stasis, expansion, shedding, and substitution. We find that the core discussion network changes remarkably quickly, with little or no lag, and that it appears to do so because both the obligations that people face and the routine activities they engage in are transformed by new institutional environments. Findings suggest that core discussion network may be less a “core” network than a highly contextual support network in which people are added and dropped as actors shift from environment to environment.     

The stability of exchange networks

Economic and sociological exchange theories predict divisions of exchange benefits given an assumed fixed network of exchange relations. Since network structure has been found to have a large impact on actors’ payoffs, actors have strong incentives for network change. We answer the question what happens to both the network structure and actor payoffs when myopic actors change their links in order to maximize their payoffs. We investigate the networks that are stable, the networks that are efficient or egalitarian with varying tie costs, and the occurrence of social dilemmas. Only few networks are stable over a wide range of tie costs, and all of them can be divided into two types: efficient networks consisting of only dyads and at most one isolate, and Pareto efficient and egalitarian cycles with an odd number of actors. Social dilemmas are observed in even-sized networks at low tie costs.     

Centrality and power revisited: actor success in group decision making

For many years, network analysts viewed positional centrality as a source of social power. More recently, laboratory studies of exchange networks have called the centrality–power link into question: under zero-sum exchange conditions, the ability of certain actors to directly exploit others has been found to account for power independent of actors' centrality. But most observers believe that in non-zero-sum communication networks, centrality should positively affect power. In this study we examine the effect of centrality on power in a communication network involving group voting on political issues. Using a model in which actors' votes are determined by the strength of their initial positions and the social pressures to which they are subjected, we conduct computer simulations to examine the extent to which actors in various network positions achieve favorable political outcomes. Our findings indicate that the link between centrality and power is highly contingent on the structure of the network. In networks with a central actor and an odd number of subgroups, central actors fail to dominate. In fact, in these networks, when peripheral actors are able to directly influence one another, the central actor becomes the least powerful in the network. In networks with a central actor and an even number of subgroups, however, the central actor dominates even in situations with connected peripherals. The highly contingent effect of centrality on power accords with the findings of exchange theorists who have studied power under zero-sum conditions. This raises questions about the nature of the distinction between communication and exchange networks.     

Social Closure and Educational Attainment

This article examines how network closure among parents affects adolescents’ educational attainment. First, we introduce a distinction between informal closure and school‐based closure. Second, we investigate whether and how the effect of informal and school‐based parental network closure varies across social contexts. Findings from the National Longitudinal Study of Adolescent Health (Add Health) and multilevel models show that parental network closure modestly impacts educational outcomes. Moreover, educational benefits of informal closure in parent networks are contingent on social context. Closure only benefits educational attainment in low‐poverty schools. In high‐poverty schools, informal closure in parent networks lowers educational attainment. The social closure generated in informal connections among parents thereby contributes to the encapsulation of disadvantage in areas of concentrated poverty, which is not the case for school‐based closure.     

Together all the way? Abeyance and co-optation of Sunni networks in Lebanon

ABSTRACT

This article assesses how social movement continuity may vary in non-democratic and repressive contexts. Using a single case study of Islamist networks in the northern Lebanese city of Tripoli over three decades, I ask: Under what conditions is social movement continuity possible, and in what form? Former studies have three levels of abeyance - activist network and personnel; movement goals and repertoires; and collective identities and symbols - are instructive. Network survival and abeyance structures can facilitate rapid mass protests in case of a facilitating external conjuncture. This analysis relies on data collected during fieldwork conducted over a decade in Tripoli, triangulated with secondary literature and primary sources in Arabic. I find that four individual-level continuity pathways are available in authoritarian contexts: continuation of activism; disengagement; co-optation; and arena shifts. These pathways should not be seen as final and stable outcomes but as fluctuating and contingent processes, or pathways. Due to the ambiguity of informal networks, co-opted movements may easily turn against the authorities once again. Moreover, local legacies of protests may be used as resources by new protest leaders.     

Collective action and network change

Network models of collective action commonly assume fixed social networks in which ties influence participation through social rewards. This implies that only certain ties are beneficial from the view of individual actors. Accordingly, in this study we allow that actors strategically revise their relations. Moreover, in our model actors also take into account possible network consequences in their participation choices. To handle the interrelatedness of networks and participation, we introduce new equilibrium concepts. Our equilibrium analysis suggests that structures that tend to segregate contributors from free riders are stable, but costless network change only promotes all-or-nothing participation and complete networks.     

Network effects on organizational decision-making: Blended social mechanisms and IPO withdrawal

This paper develops a new approach to the study of network effects in organizations and markets by proposing that structural influences on social and economic action result from contingent blends of well-understood social mechanisms. We emphasize the interplay of three different network processes: resource and information transfer, status signaling and certification, and social influence. Different mixes of these mechanisms characterize disparate networks because the obligations imposed by ties and the capacities of partners result in situations where mechanisms amplify or diminish one another. We test hypotheses about mechanism interactions using four years (1997–2000) of data on high-technology IPOs that situate organizational decisions about whether to withdraw an offering in two distinct networks. We find that network mechanisms exert multiple moderating effects on one another and that those effects vary systematically across venture capital syndicate and director interlock networks. These findings help to explain why different networks exert disparate effects, why the effects of some structures change as their larger contexts shift, and why even very successful organizations can sometimes find themselves hamstrung by their connections.     

From attitudes to social networks: National gender-role attitudes and gender differences in late-life social relationships

Studies often find gender differences in social networks in later life, but are these findings universal, or do they differ in various cultural contexts? To address this research gap, the current study examines the association between gender differences in social relationships and country-level gender-role attitudes. We combined data from the Survey of Health, Ageing and Retirement in Europe (SHARE) of individuals aged 50 years and older with country-level data on gender-role attitudes from the European Values Survey (EVS) for 15 European countries. We estimated a series of multivariate hierarchical regression models that predicted the size of the personal social network, its emotional closeness, and the proportion of the spouse, children, and friends in the network. The results indicated gender differences in social network characteristics. Women reported larger social networks and were more likely to have larger proportions of children and friends but smaller proportions of the spouse in their social networks. The magnitude of gender differences was associated with country-level gender-role attitudes. In countries with more egalitarian gender-role attitudes, women had larger networks with a larger proportion of friends compared to men. In countries with more traditional gender-role attitudes, women had larger proportions of their children and spouse in their social networks and had emotionally closer networks. Our findings suggest that the societal context and opportunity structures for social interactions play an important role in shaping the structure of women’s and men’s social relationships in later life.     

A latent space model for cognitive social structures data

This paper introduces a novel approach for modeling a set of directed, binary networks in the context of cognitive social structures (CSSs) data. We adopt a relativist approach in which no assumption is made about the existence of an underlying true network. More specifically, we rely on a generalized linear model that incorporates a bilinear structure to model transitivity effects within networks, and a hierarchical specification on the bilinear effects to borrow information across networks. This is a spatial model, in which the perception of each individual about the strength of the relationships can be explained by the perceived position of the actors (themselves and others) on a latent social space. A key goal of the model is to provide a mechanism to formally assess the agreement between each actors’ perception of their own social roles with that of the rest of the group. Our experiments with both real and simulated data show that the capabilities of our model are comparable with or, even superior to, other models for CSS data reported in the literature.     

When is brokerage negatively associated with economic benefits? Ethnic diversity,competition, and common-pool resources

There is a growing body of literature positively linking dimensions of social capital to economic benefits. Yet recent research also points to a potential “dark side” of social capital, where over-embeddedness in networks and the pressures associated with brokerage are hypothesized to constrain actors, having a negative effect on economic outcomes. This dichotomy suggests that context is important, yet the overwhelming majority of existing empirical evidence stems from socially homogenous populations in corporate and organizational settings, limiting a broader understanding of when and how context matters. We advance this discourse to a socially fragmented, ethnically diverse common-pool resource system where information is highly valuable and competition is fierce. Merging several unique datasets from Hawaii's pelagic tuna fishery, we find that network prominence, i.e., being well connected locally, has a significant, positive effect on economic productivity. In contrast, we find that brokerage, defined here as ties that bridge either structurally distinct or ethnically distinct groups, has a significant, negative effect. Taken together, our results provide empirical support to widespread claims of the value of information access in common-pool resource systems, yet suggest that in ethnically diverse, competitive environments, brokers may be penalized for sharing information across social divides. Our results thus contribute to an emerging theory on the fragile nature of brokerage that recognizes its potential perils and the importance of context.     

Social context,spatial structure and social network structure

Frequently, social networks are studied in their own right with analyses devoid of contextual details. Yet contextual features – both social and spatial – can have impacts on the networks formed within them. This idea is explored with five empirical networks representing different contexts and the use of distinct modeling strategies. These strategies include network visualizations, QAP regression, exponential random graph models, blockmodeling and a combination of blockmodels with exponential random graph models within a single framework. We start with two empirical examples of networks inside organizations. The familiar Bank Wiring Room data show that the social organization (social context) and spatial arrangement of the room help account for the social relations formed there. The second example comes from a police academy where two designed arrangements, one social and one spatial, powerfully determine the relational social structures formed by recruits. The next example is an inter-organizational network that emerged as part of a response to a natural disaster where features of the improvised context helped account for the relations that formed between organizations participating in the search and rescue mission. We then consider an anthropological example of signed relations among sub-tribes in the New Guinea highlands where the physical geography is fixed. This is followed by a trading network off the Dalmatian coast where geography and physical conditions matter. Through these examples, we show that context matters by shaping the structure of networks that form and that a variety of network analytic tools can be mobilized to reveal how networks are shaped, in part, by social and spatial contexts. Implications for studying social networks are suggested.     

Social Networks and Employment: Mechanisms (Part 1)

While substantial progress has recently been made in the literature on social networks and employment, this research has not been accompanied by a larger organizing framework. In this article, we attempt to provide such framework while reviewing the literature that addresses the context of work and employment from a social network perspective – that is, research based on the assumption that actors are embedded in networks of social relations and interactions. In particular, our review focuses on the primary mechanisms that help explain how networks may shape employment outcomes and processes, namely, by conveying resources and providing signals to others. Ties among social actors may transfer better or unique resources such as information, learning, influence, and support, which consequently may affect key employment outcomes. Ties may also provide signals concerning ability, legitimacy/trust, status, and relationship meaning. We conclude by presenting a number of alternative arguments in the literature and discussing future directions for the research on social networks and employment.     

Structure in context: A morphological view of whole network performance

Network perspectives in organizational research have focused primarily on how the embeddedness of actors shapes individual, or nodal, outcomes. Against this backdrop, a growing number of researchers have begun to adopt a wider lens on organizational networks, shifting the focus to collective, or whole network, performance. Yet, efforts to understand the relationship between whole network structure and whole network performance have produced conflicting findings, which suggests that a different approach may be needed. Drawing on macrostructural sociology, we propose a "whole network morphology" framework, which argues the whole network structure-performance relationship is contingent on other fundamental—relational and cultural—whole network dimensions. Subsequently, we undertake an application of our framework, through which we demonstrate how a morphological view helps address conflicting findings on the structure-performance relationship. We study 250 whole interorganizational networks known as Accountable Care Organizations (ACOs), which collectively comprise more than 44,000 healthcare organizations and 250,000 physicians. Consistent with previous work, we do not find a clear association between structural connectedness and performance. However, we find that a more disconnected network structure is associated with negative ACO performance when the relational strength of network ties is high. We also find evidence of better ACO performance in the presence of a physician cultural orientation when the whole network is more connected.     

Reconsidering “community liberated”: How class and the national context shape personal support networks

The “community liberated” thesis has been influential in describing contemporary social support systems. Specifically, “community liberated” argues that people do not seek support in their immediate neighborhood but rather entertain a network of far-flung ties to support-providing alters. This paper uses personal network data from six countries – Australia, Germany, the US, Austria, Hungary and Italy – to evaluate this argument and shows that the degree of liberation of one's community is strongly linked to one's socioeconomic status – specifically, one's education level. Additionally, we describe strong country-level heterogeneity in the spatial dynamics of personal support networks and find national contexts to be moderating the effect of education on community liberation, especially in Italy and Hungary, thus suggesting network geographic dispersion to be linked to national economic structures and labor markets. The paper thus elucidates the effect of two different, yet related social contexts on personal networks: the class context and the national context.     

Who are the active and central actors in the ‘rising civil society’ in Mexico?

The debate about the rise of civil society in Mexico suggests that the processes of political and economic liberalization are multiple and uneven and, thus, have different and contradictory effects on different social groups. This study takes such arguments into account and examines the nature of collective identities and social networks that are more likely to be mobilized in the rising civil society. Who, with what types of social networks and identities, are the active actors in this rising civil society in Mexico? This study also attempts to identify the central actors who take an active part in multi-sector coalitions. As such a broad coalition often leaves profound effects on politics and society, it is vital to ask which actors are likely to take an important step toward multi-sector coalition making. Using a catalog of 1797 protest campaigns collected from three Mexican newspapers between 1964 and 2000, event frequency analysis is employed to find active actors and social network analysis – blockmodel method and degree centrality measure – is applied to uncover central actors. The analyses reveal that while workers, peasants, or students continue to be very active, the centrality of these actors in contentious networks and coalitions has not increased. New central actors in the rising civil society turn out to be civic associations and NGOs formed around single issues, such as environment, retirement, and human rights. When a multi-sector coalition occurs in contemporary Mexico, NGOs and civic associations are likely to play a crucial role in it.     

The role of networks of practice and webs of influencers on farmers' engagement with and learning about agricultural innovations

Drawing on the UK research project, ‘Farmers’ understandings of GM crops within local communities’, this paper considers the application of the concepts of communities of practice and networks of practice in the agricultural context. A brief review of theories about communities of practice and networks of practice is given and some of our findings are discussed in the context of those theories.Farmers were found to be a particular type of network of practice, characterised by a weak organisational framework but with a relatively stable network of other communities of practice (or networks of practice) they interact with, which we have called a ‘web of influencers on practice’. Together, farmers’ network of practice and their web of influencers on practice represent the whole environment in which learning may occur, and so provide insights into their social learning system. Most farmers have to work at the boundary of their network of practice and their web of influencers, which creates a significant load on their knowledge management. This is in contrast to other networks of practice where only some members take on this boundary brokering role. The paper concludes that these theories (on networks and communities of practice) provide a useful lens through which to view farmers and their practice, highlighting important points for policy. However, in such contexts these theories need to be extended to include the role of a broader ‘web of influencers on practice’.     

A puzzle concerning triads in social networks: Graph constraints and the triad census

Evidence from many sources shows that triadic tendencies are important structural features of social networks (e.g. transitivity or triadic closure) and triadic configurations are the basis for both theoretical claims and substantive outcomes (e.g. strength of weak ties, tie stability, or trust). A contrasting line of research demonstrates that triads in empirical social networks are well predicted by lower order graph features (density and dyads), accounting for around 90% of the variability in triad distributions when comparing different social networks (Faust, 2006, 2007, 2008). These two sets of results present a puzzle: how can substantial triadic tendencies occur when triads in empirical social networks are largely explained by lower order graph features? This paper provides insight into the puzzle by considering constraints that lower order graph features place on the triad census. Taking a comparative perspective, it shows that triad censuses from 159 social networks of diverse species and social relations are largely explained by their lower order graph features (the dyad census) through formal constraints that force triads to occur in narrow range of configurations. Nevertheless, within these constraints, a majority of networks exhibit significant triadic patterning by departing from expectation.