The spread of online misinformation on social media is increasingly perceived as a problem for societal cohesion and democracy. The role of political leaders in this process has attracted less research attention, 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. Analyzing communications by members of the U.S. Congress on Twitter between 2011 and 2022, we show that politicians' conception of honesty has undergone a distinct shift, with authentic belief-speaking that may be decoupled from evidence becoming more prominent and more differentiated from explicitly evidence-based truth seeking. We show that for Republicans - but not Democrats - an increase of belief-speaking of 10% is associated with a decrease of 12.8 points of quality (NewsGuard scoring system) in the sources shared in a tweet. Conversely, an increase in truth-seeking language is associated with an increase in quality of sources for both parties. The results support the hypothesis that the current dissemination of misinformation in political discourse is in part driven by an alternative understanding of truth and honesty that emphasizes invocation of subjective belief at the expense of reliance on evidence.

翻译：社交媒体上在线错误信息的传播日益被视为对社会凝聚力和民主的威胁。政治领袖在这一过程中的作用受到的关注较少，尽管那些“直言不讳”的政客被部分公众视为真实和诚实，即便他们的言论缺乏证据支撑。通过分析2011年至2022年间美国国会议员在Twitter上的传播内容，我们发现政客们的诚实概念发生了明显转变：与证据可能脱钩的真实信念表达变得更加突出，并且与明确基于证据的求真行为日益分化。研究表明，对于共和党人——而非民主党人——信念表达每增加10%，推文中分享的源来源质量（NewsGuard评分系统）就会降低12.8分。相反，求真语言表述的增加与两党源来源质量的提升相关联。该结果支持以下假设：当前政治话语中错误信息的传播，部分源于对真相和诚实的替代性理解——这种理解强调主观信念的援引，而牺牲了对证据的依赖。