集體行動中的複雜傳播：大學生網絡結構對太陽花運動傳播的影響

社會行為在何種網絡結構中，能夠有效迅速的傳播？過去傳播研究的結果，大致上可分為「弱連帶/小世界傳播理論」與「複雜傳播理論」的這兩個理論典範，由於這兩個理論對於傳播門檻有不同的假設，因此關於網絡結構對傳播的影響，兩者持有不同的觀點。前者認為弱連帶的橋接特性，可以連結到更遠的社會距離，並形成小世界現象而有利傳播。後者認為社會行為存在傳播的門檻，這會導致橋接連帶的傳播功能失效，反而在冗餘的網絡結構中，容易重複地刺激行動者，達到傳播門檻閾值，而有利於傳播。再來，雖然複雜傳播理論認為傳播存在門檻，但不同人的傳播門檻可能有所不同。因此本研究更進一步分析，何種脈絡會造成傳播門檻的差異。研究使用中研院社會所「2016大學應屆畢業生網絡調查」蒐集的Facebook資料，檢驗上述兩種理論，何者較能有效解釋太陽花運動的傳播。最後研究發現，太陽花運動的傳播模式，較符合「複雜傳播理論」的預測，除了存在明顯的傳播門檻外，在冗餘連結的網絡結構中，傳播的效率也較高。此外，研究發現「身分同質性」與「結構冗餘」能夠提高傳播的機率，扮演調節傳播門檻高低的重要角色。這解釋了傳播門檻在不同人身上具有差異的可能原因。

關鍵字

複雜傳播；弱連帶；小世界；太陽花運動；社會網絡； Facebook ；大數據

並列摘要

What kind of network structures spreads social behaviors more quickly and more effectively? Past studies of diffusion generally fall into two theoretical paradigms: “Weak Tie/Small World Diffusion Theory” and “Complex Contagion Theory”. Due to differing assumptions regarding the threshold of diffusion, these two theories have opposite points of view on the effect of network structure on the spread of social behaviors. Weak Tie/Small World Diffusion Theory argues that weak ties can connect individuals across longer social distances due to the bridging effect of networks, which can produce a small world phenomenon that is favorable to diffusion. Complex Contagion Theory maintains that the bridging ties tend to fail to spread social behaviors due to a threshold on diffusion effects, because there is a threshold that exists on such networks. Rather, it is argued, behaviors are most effectively diffused through redundant networks, as these are more likely to achieve the threshold necessary to activate actors. Actors with different characteristics may have different thresholds of diffusions, so this study also explores the cause of the difference in the threshold. This paper uses Facebook data in the “2016 College Graduated Students’ Network Survey” to examine which of the previously mentioned theories can best explain the spread of the Sunflower Movement. The result shows that the diffusion pattern of the Sunflower Movement is more consistent with Complex Contagion Theory. That is, as well as there being a notable threshold that shapes the networks, it is redundant networks that are most effective in spreading social behaviors.In addition, this thesis also finds that “identity homophily” and “structure redundancy” significantly increase the likelihood of diffusion, playing an important role in moderating the diffusion threshold. This finding explains the heterogeneity in the diffusion threshold.