Media Cross-Amplification and Public Opinion : Evidence from Television Coverage of Social Media

Marques Pereira, Jaime (2025) Media Cross-Amplification and Public Opinion : Evidence from Television Coverage of Social Media. Working Paper. Lancaster University, Department of Economics, Lancaster.

Abstract

I study how social media messages are amplified by television news and how this amplification shapes public opinion. Using high-frequency data on President Trump’s tweets and cable transcripts, I show that Trump’s tweets caused near-immediate shifts in cable coverage, providing causal evidence of agenda-setting power. Linking text-on-screen data to a large public opinion survey, I find that broadcasts of Trump’s tweets causally shifted viewers’ approval of Trump and their 2020 voting intentions, widening gaps across TV audiences. Additional evidence shows that this mechanism is not specific to Trump, with cable news actively amplifying online statements by other prominent U.S. politicians.