Platform affordances and spiral of silence: How perceived differences between Facebook and Twitter influence opinion expression online

This study examines how perceived differences in the affordances of social media platforms influence users’ willingness to express opinions on a controversial issue, viz., systemic racism. Drawing on a U.S. nationally representative survey, our analysis suggests that fear of social isolation has a significant effect on Facebook but not on Twitter. Moreover, three platform affordances — network association, anonymity, and social presence — moderate the relationship on Facebook, while anonymity has a direct positive effect on Twitter. We argue that increased perceived network association and social presence and reduced perceived anonymity on Facebook result in higher levels of self-censorship. Twitter’s interest-based ties, on the other hand, enhance anonymity and, with it, the willingness to speak on controversial topics.