在選舉競爭的場域中，負面競選成為政黨與候選人間愈來愈常用的競選手段。從學理的角度來看，學者認為負面訊息對選民投票行為的影響，甚至更大於正面資訊。然而在實證上，絕大多數的選民都不認為他們的投票受到負面資訊的影響。為了理解理論與實證上的差距，本文重新探索負面訊息與選民投票行為的關係。筆者認為，由於選民慣於依賴政黨認同傾向做為篩選政治資訊的捷徑，因此政黨認同的強度不但影響了選民的投票決定，也左右了選民在負面資訊接受上的方向與多寡。我們進一步利用結構方程式模型分析TEDS2010C在台北、台中、高雄三個直轄市長選舉後所進行的調查資料，統計結果不但顯示受訪者的政黨認同影響了他們的投票抉擇及在負面資訊上的接收方向與程度，同時也進一步證明負面資訊對於選民投票行為的影響實為有限。 In modern electoral campaign, especially that in most single member districts, negative campaigning has become a popular strategy for most candidates. They broadcast negative information about their opponents in order to discourage their supporters and hence garner, if any, electoral advantage and maximize chances of election. Despite its prevalence, scholars still have not achieved an agreement on whether negative campaign is determinant to voting behavior. Especially, while statistics shows that receiving negative information is negatively associated with voting decisions, we found that interviewees generally asserted that the messages did not affect their voting decisions at all. To solve the self-contradictory puzzle, following conventional wisdom, we assert that voters apply party identification as a shortcut to sift political information. Thus, they ignore the negative information about their preferred candidate but reinforce their detestation of the candidates they do not like. We further examine our theory by incorporating the TEDS2010C data with structural equation model. The analytical result supports our hypotheses and shows that voters' party identity and voting decision significantly influence the negative information they received. Nevertheless, the negative information does not have significant influence on voters' voting decisions.