The differential effect of a multi-party (predominantly one-party) versus two-party system on the relationship between social network and voting behavior: an analysis of the 2001 Japanese House of Councilors and 2000 US presidential elections

Abstract

In a comparative analysis of American and Japanese voting behavior, the effects of social networks on voting behavior and the expression of political opinion were Investigated. Using an Interpersonal Political Environment (IPE) approach, which assumes that social networks form influential environments with respect to such behavior, a consistent pattern of influence via social networks was detected in both countries. If surrounded by LDP (Liberal Democratic Party) supporters, the data suggest that Japanese voters tend to vote for the LDP even after controlling party identification. The same is true for DPJ (Democratic Party of Japan) voters in Japan as well as for Republican and Democrat voters in US presidential elections. A similar pattern is also observed with respect to voluntary expressions of opinion about politicians. As these positive and negative expressions are made voluntarily without significant group pressure, the effects of social networks appear to be caused by the acceptance of the viewpoints of others within IPEs as the political reality. It was also revealed that the effect of an IPE on voting behavior is larger in the US than in Japan. Further analyses indicate that the difference between the two countries in this respect is largely attributable to institutional differences between the US and Japan, specifically the political party configuration (the two-party system, versus the multi-party system with a dominant and several smaller parties, which is often described as one-party dominant).