HPC › Social › Glossary
Social capital is the collective value embedded in social networks, comprising the norms of reciprocity, trust, and mutual obligation that arise from relationships between people. Putnam distinguishes two core forms: bonding capital, which strengthens ties within close-knit groups, and bridging capital, which connects people across diverse social divides to expand access to information and resources.
A third dimension, linking capital, describes vertical ties between citizens and institutions, extending the framework beyond horizontal networks.
How it works
Putnam frames social capital as a resource communities accumulate through sustained interaction. Bonding social capital operates within dense, homogeneous networks, including families, close peer groups, and tightly organised community associations. These ties generate strong norms of solidarity and mutual aid, providing members with the means to get by during hardship. 1 Bridging social capital spans weaker ties across heterogeneous groups. These cross-cutting connections function as conduits for novel information and resources outside one's immediate network, helping people get ahead rather than merely survive. 1
The bonding-bridging distinction is better understood as a continuum than a binary classification. The same relationship may exhibit properties of both forms depending on context, and communities typically hold varying degrees of each simultaneously. 12 Woolcock extended the framework by identifying linking capital: vertical ties connecting citizens to formal institutions and authority structures. 2 Where bonding and bridging capital operate largely among social peers, linking capital determines how effectively a community's social resources translate into access to state services and broader economic opportunity.
Example
A professional moving to an unfamiliar city finds her densely connected network of former colleagues provides warmth and mutual support. Six months later, a contact from a disparate industry event surfaces a role at an organisation she would not have encountered through existing connections. The weaker, cross-cutting tie delivers what the tight network could not.
Both forms are necessary: bonding capital provides resilience, while bridging capital expands the ceiling of what is reachable.
Why it matters
Social capital's relevance extends well beyond sociology. A synthesis of 20 systematic reviews found consistent evidence that it is protective against mortality and associated with better mental and physical health; the same analysis also recorded numerous non-significant and negative associations, underscoring that effects are context-dependent rather than uniformly positive. 3 Poortinga's analysis of a representative UK sample found that community-level social capital predicted self-rated health independently of individual social support, suggesting the collective dimension carries a distinct health premium beyond personal relationships. 4
Social capital also carries a notable downside. High bonding capital within a group can generate insularity, in-group favouritism, and the systematic exclusion of outsiders, a dynamic Putnam termed the 'dark side' of social capital. 1 Woolcock's cross-national analysis shows that societies combining strong bridging networks with effective state-society linkages achieve better economic outcomes than those with high bonding but weak bridging capital. 2 The implication is that cultivating all three forms, rather than maximising any single one, produces the most robust social infrastructure.
What is the difference between bonding and bridging social capital?+
Bonding social capital describes strong ties within homogeneous groups, such as family and close friends, generating solidarity and mutual aid. Bridging social capital links people across diverse groups through weaker connections that carry novel information and access to resources outside one's existing network. Both are necessary and can coexist within the same relationship.
How does social capital affect health outcomes?+
A synthesis of 20 systematic reviews found social capital is consistently associated with lower mortality and better mental and physical health. However, effects are context-dependent: the same synthesis recorded numerous non-significant and negative associations. Community-level social capital carries health benefits beyond what individual social relationships alone can explain.
What did Putnam mean by social capital and how did he measure it?+
Putnam defined social capital as the collective value embedded in social networks and the norms of reciprocity and trust that arise from them. He measured it through indicators including voluntary association membership, informal social contact, and survey measures of generalised trust, documenting a sustained decline in the United States across the latter twentieth century.
Can social capital be harmful?+
Yes. Putnam identified the 'dark side' of social capital: tight bonding within a group can produce insularity, in-group favouritism, and exclusion of outsiders. Woolcock's cross-national analysis showed that societies with high bonding capital but weak bridging connections and ineffective institutional linkages perform worse on economic development metrics than more balanced societies.
