隨著社群媒體被廣泛使用，政治溝通的型態也產生變化。在全球許多民主國家，包括臺灣，政黨與候選人在選舉時大量使用不同的社群媒體，例如臉書、推特等，來傳遞政見或是想要傳遞給選民的訊息。基本上，社群媒體在政治溝通中扮演的是價值中立的工具性角色，並且能夠刺激市民社會中的政治參與。已經有許多研究指出，社群媒體在社會運動中的角色越來越重要，但是對於政黨、候選人在選舉中如何應用社群媒體的相關討論，仍舊不是很明確。本研究以臺灣2018年縣市長選舉為例，透過實證研究討論候選人在臉書經營上的特殊性，主要的發現包括四項：1.現任者的臉書傾向宣傳政績訴求回溯性選民、挑戰者則是提出願景訴求前瞻性選民的支持；2.基於選制鼓勵，挑戰者容易出現攻擊型態，也就是接近負面競選的發文；3.選情與候選人類型會影響發文型態；以及4.縣市議員會尋求同框效應。

Political communication has changed because of the popularity of social media. In Taiwan and many other democracies, political parties and candidates use social media platforms such as Facebook, Twitter, and Instagram to disseminate political views and communicate messages to voters. Basically, social media plays a value-neutral role in political communication and promotes political participation in civil society. Many studies show that social media plays an important role in social movements. However, it is still unclear how to compare the different social media strategies employed by politicians or political parties. In elections, social media strategies depend on to the type of voter being courted, such as retrospective voters or prospective voters. This paper compares social media posts during the 2018 municipal elections in Taiwan to explore the different models or strategies of social media messaging employed by different types of candidates. We address some empirical studies on this topic in 2018 elections in Taiwan and point out three findings: 1. Incumbents seek to retrospective voters and challengers seek to prospective voters; 2. Polls will influences the electoral campaign on FB; and 3. County councilors will seek to promote themselves on FB with the mayoral candidate.

社群媒體;臉書;回溯性投票;前瞻性投票;負面競選;同框

Social Media; Facebook; Retrospective Voting; Prospective Voting; Negative Campaign; Bandwagon Effects