Common approaches for improving the mental health of the population in general and of vulnerable groups in particular include policies to address social determinants and the expansion of professional health services. Both approaches have substantial limitations in practice. A more promising option is actions that utilize resources that either already exist or can easily be generated in local communities. Examples are provided for various local initiatives with the potential to facilitate helpful interactions and relationships that are likely to benefit the mental health of significant parts of the population. Developing and implementing such initiatives is a challenge to communities, while their evaluation may require innovative methods in research.

Group-living creates stresses that, all else equal, naturally lead to group fragmentation, and hence loss of the benefits that group-living provides. How species that live in large stable groups counteract these forces is not well understood. I use comparative data on grooming networks and cognitive abilities in primates to show that living in large, stable groups has involved a series of structural solutions designed to create chains of ‘friendship’ (friends-of-friends effects), increased investment in bonding behaviours (made possible by dietary adjustments) to ensure that coalitions work effectively, and neuronally expensive cognitive skills of the kind known to underpin social relationships in humans. The first ensures that individuals synchronise their activity cycles; the second allows the stresses created by group-living to be defused; and the third allows a large number of weak ties to be managed. Between them, these create a form of multilevel sociality based on strong versus weak ties similar to that found in human social networks. In primates, these strategies appear successively at quite specific group sizes, suggesting that they are solutions to ‘glass ceilings’ that would otherwise limit the range of group sizes that animals can live in (and hence the habitats they can occupy). This sequence maps closely onto the grades now known to underpin the Social Brain Hypothesis and the fractal pattern that is known to optimise information flow round networks.

Networks are a subject of growing research interest. Yet union networks, particularly networks of delegates, and ways to build them, are still poorly understood. This is a study of the meaning that workplace union delegates assign to networks of support. It explores the characteristics of effective delegate and union networks and influences upon them. Effective networks are a combination of strong and weak ties, such that delegates sometimes do not recognise they are part of a network. Our three-stage research methodology involved delegate focus groups, a paper-based self-completion questionnaire of recently trained delegates (N=473) and a follow-up telephone survey (N=145). It found that organisers were key to creation of internal workplace networks (although they did not necessarily establish them) and in providing a bridge for delegates with external networks. They were the key support person for many delegates. Networks took a variety of forms. Only a minority were formalised. A majority were mainly internal to the workplace. Social media were rarely used, with little intention of using them more, and were, we suspect, underutilised.

The great urbanist Jane Jacobs details how urban planning impacts the social interactions and social networks responsible for the economic death or life of a city. How might urban planning impinge on the moral values that underlie that development? I draw on Jacobs’s work on the moral foundations of commercial society to identify two “urban values” (tolerance and innovation). I then examine how these values support the social networks and processes that facilitate urban-based innovation and how urban planning can strengthen or undermine those values. I use the examples of urban planning in the 15th Ward of Syracuse, New York and of city building in the private development of Cayalá in Guatemala City to illustrate these points.

Social influence is frequently measured through an ego's direct ties. Although influence may also stem from an ego's indirect ties, reference group, and casual contacts, it is difficult to capture their impact using existing network methods. We identify and trace the influence stemming from an ego's “familiar others,” consisting of those socially similar individuals with whom the ego comes in contact at school, but does not necessarily share a relationship. To evaluate the role of familiar others, we investigate unhealthy weight behaviors in adolescence using data from the National Longitudinal Study of Adolescent to Adult Health. Our results demonstrate that familiar others' unhealthy weight-related behaviors are strong predictors of the ego's own weight behaviors, net of immediate alters' behaviors, and individual-level characteristics. Further, we find that this relationship is stronger and more robust than that between egos and their direct ties. These results suggest that familiar others constitute a key source of social influence that is distinct from the influence of network alters.

Social ties are strongly related to well-being. But what characterizes this relationship? This study investigates social mechanisms explaining how social ties affect well-being through social integration and social influence, and how well-being affects social ties through social selection. We hypothesize that highly integrated individuals–those with more extensive and dense friendship networks–report higher emotional well-being than others. Moreover, emotional well-being should be influenced by the well-being of close friends. Finally, well-being should affect friendship selection when individuals prefer others with higher levels of well-being, and others whose well-being is similar to theirs. We test our hypotheses using longitudinal social network and well-being data of 117 individuals living in a graduate housing community. The application of a novel extension of Stochastic Actor-Oriented Models for ordered networks (ordered SAOMs) allows us to detail and test our hypotheses for weak- and strong-tied friendship networks simultaneously. Results do not support our social integration and social influence hypotheses but provide evidence for selection: individuals with higher emotional well-being tend to have more strong-tied friends, and there are homophily processes regarding emotional well-being in strong-tied networks. Our study highlights the two-directional relationship between social ties and well-being, and demonstrates the importance of considering different tie strengths for various social processes.

A wide variety of networked systems in human societies are composed of repeated communications between actors. A dyadic relationship made up of repeated interactions may be reciprocal (both actors have the same probability of directing a communication attempt to the other) or non-reciprocal (one actor has a higher probability of initiating a communication attempt than the other). In this paper we propose a theoretically motivated index of reciprocity appropriate for networks formed from repeated interactions based on these probabilities. We go on to examine the distribution of reciprocity in a large-scale social network built from trace-logs of over a billion cell-phone communication events across millions of actors in a large industrialized country. We find that while most relationships tend toward reciprocity, a substantial minority of relationships exhibit large levels of non-reciprocity. This is puzzling because behavioral theories in social science predict that persons will selectively terminate non-reciprocal relationships, keeping only those that approach reciprocity. We point to two structural features of human communication behavior and relationship formation—the division of contacts into strong and weak ties and degree-based assortativity—that either help or hinder the ability of persons to obtain communicative balance in their relationships. We examine the extent to which deviations from reciprocity in the observed network are partially traceable to the operation of these countervailing tendencies.

One of the most influential applications of the concepts, methods and measures of social network analysis to the study of the social support transactions of older adults is the convoy model of social support. We draw on recent debates in network methodology to provide an assessment of the convoy model that explores the role of weak ties in the support networks of older adults. The social networks generated by the target diagram which operationalizes the convoy model display the structural and functional characteristics set out in its theoretical arguments. But not all of the ties constituting these networks are conduits of social support and, more importantly, these social networks do not include all supporting and supported others. The target diagram identifies core support networks; therefore, support flowing through weak ties is missed when it is used to set the boundaries of support networks. Expanding our picture of the support networks of older adults to take systematic account of weak ties and the emotional aid, instrumental assistance, and companionship that flow through them will enhance the effectiveness of support interventions that target older adults.