From alternative conceptions of honesty to alternative facts in communications by U.S. politicians

The spread of online misinformation is increasingly perceived as a problem for societal cohesion and democracy. Much attention has focused on the role of social media as a vector of misinformation. The role of political leaders has attracted less research attention, even though leaders demonstrably influence media coverage and public opinion, and even though politicians who "speak their mind" are perceived by segments of the public as authentic and honest even if their statements are unsupported by evidence or facts. Here we show that in the last decade, U.S. politicians' conception of truth has undergone a distinct shift, with authentic but evidence-free belief-speaking becoming more prominent and more differentiated from evidence-based truth seeking. We analyze communications by members of the U.S. Congress on Twitter between 2011 and 2022 and show that political speech has fractured into two distinct components related to belief-speaking and evidence-based truth-seeking, respectively, and that belief-speaking, but not truth-seeking, can be associated with the sharing of untrustworthy information. We show that in tweets by conservative members of Congress, an increase in belief-speaking of 10% is associated with a decrease of 13.7 points of quality (using the NewsGuard scoring system) in the sources shared in a tweet. In addition, we find that an increase of belief-speaking language by 10% in the shared articles themselves is associated with a drop in NewsGuard score of 7.9 points for members of both parties. By contrast, increase in truth-seeking language in tweets and articles is associated with an increase in quality of sources. The results support the hypothesis that the current dissemination of misinformation in political discourse is in part driven by a new understanding of truth and honesty that has replaced reliance on evidence with the invocation of subjective belief.