Notions about innovation have undergone a sea change in the last decade. Where once we embraced the idea of the lone scientist or entrepreneur and divine inspiration, we now see networks of creative people collaborating in the myriad steps from brainstorm to finished product. This new understanding has aligned perfectly with the emerging concept of social capital, the idea that strong social networks—tight communities bound by shared norms, trust, and reciprocity—enhance cooperation and productivity. When people belong to communities with high levels of social capital, the theory goes, they’re far more willing to work together and take chances on risky ideas. It followed that high social capital would fuel innovation.

A version of this article appeared in the August 2002 issue of Harvard Business Review.