Trumpism, climate and COVID: Social bases of the new science rejection

support for treating Trump support as an intervening variable; a similar approach is taken in this paper. Conspiratorial thinking has been a conspicuous feature of US politics at least since at least the 1950s [34] and appears to be growing in prominence across a wide range of topics [35,36]. Although some conspiracy beliefs focus on political leaders (e.g., Obama is Muslim, or Trump really won the 2020 election), many others have been directed against scientists [37], on topics including climate change [38,39], vaccinations [39] and COVID-19 [5,40–42]. There are con- spiracy beliefs discounting both anthropogenic climate change and the seriousness of COVID- 19. Showing that specifically climate or COVID-related beliefs predict other views on those same topics seems circular, however. The analysis that follows instead tests an indicator for receptivity to extreme conspiratorial beliefs that have not been much politicized and are unre- lated to climate or COVID. Multiple studies on the social bases of views on climate change and other environmental problems have replicated two interactions involving political identity. The most common are information×political-identity effects in which, for example, concerns about climate change increase with education among liberals and moderates, but do not increase and may even decrease with education among the most conservative. Variations include party, ideology or worldview used as political-identity indicators; and education [12,14,43–47], self-assessed

understanding [13,48], tested science literacy [49,50], or numerical literacy [51,52] as informa- tion indicators. Similar interactions have been found with non-climate dependent variables relating to vaccines [53], perceptions of local flooding or weather trends [54–56], renewable energy [57], and other environment-related issues [58,59]. In all these findings the interactions take a similar form, often graphed with a right-facing megaphone shape: the best-educated partisans stand the farthest apart (e.g., Fig 3A–3D in [12]). Such information×identity-type interactions reflect the influence of partisan cueing— absorbing cues from partisan elites, co-partisans, or (negatively) perceived antagonists, regard- ing which beliefs are appropriate for your identity—as a heuristic in “forming” your own views on difficult issues [60–64]. Better-educated or otherwise information-rich individuals tend to be more sensitive to partisan cues. The public-opinion impacts of messaging from political and partisan-media elites have been prominent regarding both climate change [27,61,64–67] and COVID-19 [18,68,69]. Information-processing behaviors such as biased assimilation [13,70] and motivated reasoning [71–75], to the extent these are stronger among information elites, likely contribute to the observed information×identity interactions as well. A second, less dramatic interaction effect follows from survey reports that Americans increasingly choose to associate with people of their own political persuasion, a pattern that

intensifies polarization [76–78]. Political identity×friends-type interactions have been con- firmed in several recent studies involving local weather trends [56], wildlife management [79], and local weather or climate [80]. Their common form is that political-identity effects are stronger, or partisan gradients steeper, when most of the respondent’s friends are reported as belonging to the same political party. This may be especially true among conservatives. 3. Research questions and hypotheses Sociopolitical identity—as indicated by political party, ideology, or most recently support for Donald Trump—has been consistently linked to rejection of both anthropogenic climate change (ACC) and COVID-19 vaccination. It is not established to what extent other basic respondent characteristics such as age, gender, race, income, religion or income also show sim- ilar or divergent patterns across these two important cases of science rejection. Exploring such comparisons provides the basic motivation for our analysis. Because the social bases of ACC PLOS ONE Trumpism, climate and COVID PLOS ONE | https://doi.org/10.1371/journal.pone.0293059 January 10, 2024 3 / 20