The role of political interest in the relationships between privacy concerns, social network size, and political expression on Facebook, Twitter, and Instagram

Studies on the predictors of using social media for political purposes reveal some unexpected complexities: users often disregard institutional privacy concerns to discuss politics online, and the size of social networks positively correlates with political expression on social media. Building on the privacy calculus theory, we explore how political interest interacts with privacy concerns and social network size when users decide to engage in political expression on social media. This study utilizes survey data from four countries (the US, UK, France, and Canada) collected in 2019 (n = 6,291), encompassing three social media platforms: Facebook, Instagram, and Twitter. We find that privacy concerns are negatively related to expression on social media. Larger social networks positively relate to political expression, especially on Twitter. Political interest plays an important moderating role: highly politically interested users discount privacy concerns and opt to post political content. These findings replicate across all three platforms.