Communication networks play an important role in the process of political socialization. This article, based on Taiwan's 2002 Taipei and Kaohsiung mayoral election data, investigates the extent to which political discussion with family and close friends affects changes in vote choices. Using two definitions of changes in vote choice—vote switching and partisan defection—the empirical findings support Alan Zuckerman and his followers' structural theory and partially sustain Paul Beck's social support theory. First, partisan voters in both cities who perceive great heterogeneity in their communication networks are likely to switch their vote in two consecutive elections. Second, partisan voters in Kaohsiung who frequently discuss politics within communication networks are not likely to defect their party identification. The implications of the findings for the development of deliberative democracy are discussed.
