To access, purchase, authenticate, or subscribe to the full-text of this article, please visit this link: http://dx.doi.org/10.1016/j.jesp.2017.07.008 Byline: Nicholas D. Duran [email@example.com] (a,*,1), Stephen P. Nicholson (b,2), Rick Dale (b,3) Keywords Attitude expression; Motivated reasoning; Need for accuracy; Political beliefs; Political conspiracies; Action dynamics; Implicit attitudes Highlights * We use response dynamics as a covert measure of endorsing or disavowing political conspiracies * Despite denying political conspiracies, Republicans show a hidden attraction to them * Conversely, among participants who endorse political conspiracies, Democrats show a hidden preference for the truth * Effects are more or less pronounced depending on partisan worldview * We interpret results with a framework of motivated reasoning and accuracy/self-presentation biases Abstract In this study, we used a mouse-tracking paradigm to capture subtle processing dynamics that may occur when people spontaneously endorse or disavow political conspiracies. Rather than exclusively focus on explicit, endpoint responses, we examined the underlying temptation to respond opposite of what is overtly reported. Our results revealed such tendencies in participants' arm movements as they provided "true" or "false" answers to political conspiracy statements relative to baseline statements. These effects were strongly modulated by whether participants identified with the Republican or Democratic parties. To interpret our findings, we argue that political conspiracies tap into hidden biases that may be at odds with each other, such that, even for nonbelievers of a particular conspiracy, there is an implicit appeal for ideologically-aligned conspiracies driven by motivated reasoning biases, and for believers, an implicit aversion to the same conspiracies driven by accuracy and self-presentation needs. Author Affiliation: (a) Arizona State University, United States (b) University of California, Merced, United States * Corresponding author at: School of Social and Behavioral Sciences, Arizona State University, 4701 West Thunderbird Road, Glendale, AZ 85306, United States. Article History: Received 8 June 2016; Revised 19 July 2017; Accepted 21 July 2017 (footnote)1 Nicholas D. Duran, School of Social and Behavioral Sciences, Arizona State University, United States. (footnote)2 Stephen P. Nicholson, Political Science, University of California, Merced, United States. (footnote)3 Rick Dale, Cognitive and Information Sciences, University of California, Merced, United States.