Polarized Speech on Online Platforms in the American Political Context (2308.15556v3)

Abstract: Using LLMs, we analyze approximately 2.5 billion comments from Reddit and Twitter across 1.7 million accounts spanning 2007 to 2023 to study the prevalence and evolution of polarized rhetoric in American political discourse. Our findings show rising outgroup polarization on both platforms, with each new cohort of users displaying higher polarization than the last, and a small fraction of users contributing disproportionately to negative polarization. Polarization varies consistently by topic: right-leaning users are twice as likely to use polarized rhetoric around immigration, while left-leaning users are more polarized on healthcare. On Twitter, U.S. politicians on the left have been consistently more polarized than everyday users, but in the past four years, politicians on the right have experienced the sharpest rise in polarization, surpassing journalists, media, and everyday users. Today, politicians, the group listened to the most for their political rhetoric, are far more polarized than everyday users. On Reddit, a few communities dominate polarized discussions, with the rise and eventual ban of r/TheDonald significantly shaping polarization trends on the right. Our large-scale analysis reveals previously unknown patterns of polarization across groups and topics on two major social media platforms.