本研究探究社交网站为社会政治议题互动讨论所提供的话语空间，尤其是使用者在此空间中的人际互动动机及网络公民参与，并在此基础上探讨社交网络异质性与认知失调之假设关系，尝试通过选择性修正来回答社会政治议题网络讨论中何以出现“友人‘辩’成路人”之现象。通过对微博用户（N=287）进行问卷调查，发现人际互动动机、网络公民参与度对网络讨论的异质性有正向相关，而更大程度的异质性也会导致更多的认知失调。在社会政治议题讨论中发生认知失调的情况下，人们可能受到个人意识形态倾向的影响来进行人际关系的修正。

This study explores the discourse space provided by the Internet technology especially for the social issue discussion, and the changed interpersonal relationship during those online discussions. Based on literature reviews, this study proposes a causal relation between network heterogeneity and cognitive dissonance, trying to explain the emerging “unfriend” phenomenon. Via analyzing the result of questionnaire designed for Weibo users (N = 287), the result reveals that interpersonal interaction motives, online civic participations are positive to network heterogeneity, and higher heterogeneity will result in higher degree of cognitive incongruity. To ease cognitive dissonance, people with a conservative inclined ideology are more likely to adjust their interpersonal relationship.