The evolution and existence of stable trust relations have been studied extensively in the context of social theory. However, reputation systems or trust schemes have only been recently used in the domain of wireless ad hoc net works. It has been shown that these schemes provide positive results as a self-policing mechanism for the routing of data in wireless ad hoc network security. This paper develops a relationship between the trust concepts in the social network theory and wireless ad hoc networks. In addition, the paper maps existing trust schemes in wireless ad hoc networks to a long-standing theory in social networks. Most importantly, a refined model of trust evaluation in social networks is constructed and mapped to a new trust scheme for ad hoc networks. The new trust scheme is analyzed and shown to outperform existing schemes using scenario and simulation analysis.