Repetition increases belief in climate-skeptical claims, even for climate science endorsers

Further, we present mean truth ratings for each skeptic claim acting as either a repeated or non-repeated claim to allow an inspection of possible item effects. In short, we find a consis- tent pattern in the effect of repetition for Experiment 1 (S1 Fig) and Experiment 2 (S2 Fig). Stronger tests of the ITE for counter-attitudinal claims ITE held for subjectively counter-attitudinal claims. It is conceivable that some partici- pants did not recognize our pilot-tested skeptic claims as skeptic-aligning and hence counter- attitudinal. To address this possibility, we asked participants in Experiment 2 to identify whether a claim aligns with climate science or climate skeptics. This allowed for an analysis where we treated the claims as scientist-aligned or skeptic-aligned based on each participant’s personal classification at the end of the study. We inspected only truth ratings for claims Fig 3. Raincloud plot of truth rating differences between repeated and non-repeated claims across claim types (all, scientist, skeptic, weather) in Experiment 1. Shown is the difference between the truth ratings when claims were repeated vs. not repeated, computed as (mean of repeated claims minus mean of non-repeated claims), for each participant. Values above zero reflect a repetition-induced truth effect, where on average repeated claims are rated as more true than non-repeated claims. https://doi.org/10.1371/journal.pone.0307294.g003 PLOS ONE Illusory truth effect for climate-skeptical claims PLOS ONE | https://doi.org/10.1371/journal.pone.0307294 August 7, 2024 10 / 19