Trust Me, I Cite Science: How Political Communication Drawing on Science Affects Message Credibility and Communicator Trustworthiness

The interplay between science and politics is increasingly complex and contentious, especially in times of global crises and polarized public debates. While science is often invoked in political discourse with calls to “follow the science,” its role in politics is rarely straightforward. Scientific evidence does not automatically deliver unequivocal policy prescriptions, nor does it offer simple and settled claims for politicians to rely on. Instead, scientific knowledge is often provisional, contested, and characterized by uncertainty, especially when it addresses complex social problems or emerging risks. When scientific evidence enters the political arena, it is therefore filtered through competing interests, ideological positions, and strategic communication goals. Rather than serving as a neutral guide, science may become a symbolic resource that political actors deploy selectively to justify predetermined policy positions or to enhance their own credibility. Existing research suggests that politicians may strategically reference scientific findings, expert authority, or generalized appeals to “knowledge” in ways that align with their political objectives. However, the effects of such communication strategies on public perceptions remain empirically underexplored. This study addresses this gap by examining how science-related political communication shapes perceived message credibility and communicator trustworthiness. Drawing on insights from science communication, political communication, and motivated reasoning research, it conceptualizes public responses to science-related political messages as the product of both message characteristics and audience predispositions. The study explicitly considers how different communicative strategies interact with individual attitudes toward science and politics. Empirically, the study tests hypotheses across three conceptual dimensions. First, it examines source credibility effects by comparing messages delivered by scientists versus politicians and by varying the type of evidence invoked, including references to scientific studies, scientific reputation, or common sense reasoning. Second, it analyzes the effects of rhetorical strategies used to justify political decision-making, distinguishing between deliberative appeals that emphasize discussion and political compromise, technocratic appeals that stress the importance of expertise and epistemic authority, and populist appeals that foreground the “will of the people.” Third, it investigates how science-populist attitudes and pre-existing issue attitudes moderate these effects, thereby accounting for heterogeneity in audience responses. The findings of a pre-registered factorial survey experiment conducted in Austria (N = 552) show that source credibility and the choice of evidence are primary drivers of perceived credibility and trustworthiness. In contrast, rhetorical strategies related to decision-making processes have no significant effect. Notably, science-populist attitudes strongly influence which epistemic authorities respondents consider the ideal bases for political decisions. Although scientific evidence and scientific reputation are generally perceived as legitimate sources of epistemic authority, respondents with high science-populist attitudes assign greater weight to appeals to common sense than to the epistemic authority of science itself. These findings suggest that politicians communicating about science should pay particular attention to the sources underpinning their arguments and the specific audiences they address. The study provides novel empirical insights into how communicative strategies shape public trust in science-related political communication, offering implications for safeguarding trust in science and improving the credibility and trustworthiness of political communication in increasingly polarized environments.