Bowling Alone: Revised and Updated: The Collapse and Revival of American Community

by Robert D. Putnam

the core idea of social capital theory is that social networks have value.

Whereas physical capital refers to physical objects and human capital refers to properties of individuals, social capital refers to connections among individuals—social networks and the norms of reciprocity and trustworthiness that arise from them. In that sense social capital is closely related to what some have called “civic virtue.” The difference is that “social capital” calls attention to the fact that civic virtue is most powerful when embedded in a dense network of reciprocal social relations. A society of many virtuous but isolated individuals is not necessarily rich in social capital.

reciprocity is specific: I’ll do this for you if you do that for me.

generalized reciprocity: I’ll do this for you without expecting anything specific back from you,

social capital—that is, social networks and the associated norms of reciprocity—comes

bridging social capital can generate broader identities and reciprocity, whereas bonding social capital bolsters our narrower selves.

Bonding social capital, by creating strong in-group loyalty, may also create strong out-group antagonism,