Social media use, opinion polarization, social movement participation, and voting: The case of Hong Kong

This chapter explores the impact of social network platforms on political polarization and political participation behavior in the context of Hong Kong, particularly in the aftermath of the anti-extradition bill movement. The chapter presents the findings from a post-election survey conducted in early 2020. The survey data provides a descriptive analysis of individuals’ exposure to social media and its influence on their political attitude and behavior. The analysis identifies two key findings. First, it is observed that exposure to social media contributes to opinion polarization, with frequent users tending to hold more extreme opinions. The causal direction of this relationship is difficult to determine, as it could be a result of social media reinforcing existing attitudes or individuals with strong political views seeking out like-minded content. Second, the study reveals that exposure to social media platforms increases the likelihood of social movement participation, particularly in protests. Emotional information shared on social networks can facilitate the spread of negative emotions, which, in turn, can fuel endorsement for the use of violence during protests. Overall, the study highlights the influence of social media on opinion polarization and its mobilization effects on social movement participation, emphasizing the need for further research to understand the complex dynamics between social media use, political attitudes, and behavior. © 2025 selection and editorial matter, Erica Guevara and Anaïs Theviot; individual chapters, the contributors.