Whole-Net Base and Social Capital:

Stratified Opportunity Structure of Social Capital

抄録

Social capital works on whole networks and its process (chance of investment and return) is structured along with the configuration of them. However, in an ordinary survey design, it is quite difficult to locate respondents' personal networks on such macro configurations. Here we introduce a concept of whole-net base. It is as a shared attribute that indicates a latent whole network behind it. Keeping contact with a schoolmate, for example, indicates that the tie is a part of a whole network that consists of latently all graduates of the school. Under a question how social capital is built in the stratification process, we analyze a personal network data from the viewpoint of investment-return through various friends-net bases. The results show that; 1) the upper stratum invests and gets return more than the lower, especially on job-net and school-net bases that directly correspond to socio-economic status, however, 2) it is the lower stratum in which efficient investment (the tendency that more investment correspond to more return) is observed clearly, moreover, the observation is not limited to the specific whole-net base. These suggest a dynamic opportunity structure of social capital: while it reinforces the advantageous socio-economic positioning for the upper stratum, at the same time, it also makes their life chances greater for the lower stratum. However, we have to pay attention to those elder people in the lower of lower strata who do not have any access to social capital.