“…Informal institutions, however, may be endogenously enforced; they are upheld by mutual agreement among the social actors involved, or by relations of power and authority between them. Recent work on institutions stresses the socially``embedded'' nature of informal institutions, or the multiplicity of institutional relations in which people are engaged at any one time (Runge, 1986;Mearns, 1996b;Swallow et al, 1997). As argued in the burgeoning literature on social capital, trust and networks of civic engagement (e.g., Gambetta, 1988;Putnam, Leonardi and Nanetti, 1993;Stewart, 1996;Humphrey and Schmitz, 1996;Mearns, 1996c;Dasgupta, 1996), multiple involvement may promote mutual assurance among social actors, promoting cooperation and collective action.…”