This paper reviews the origins and definitions of social capital in the writings
of Bourdieu, Loury, and Coleman, among other authors. It distinguishes four
sources of social capital and examines their dynamics. Applications of the
concept in the sociological literature emphasize its role in social control, in
family support, and in benefits mediated by extrafamilial networks. I provide
examples of each of these positive functions. Negative consequences of the
same processes also deserve attention for a balanced picture of the forces at
play. I review four such consequences and illustrate them with relevant examples.
Recent writings on social capital have extended the concept from an
individual asset to a feature of communities and even nations. The final sections
describe this conceptual stretch and examine its limitations. I argue
that, as shorthand for the positive consequences of sociability, social capital
has a definite place in sociological theory. However, excessive extensions of
the concept may jeopardize its heuristic value..