Communicating highly divergent levels of scientific and social consensus: its effects on people’s scientific beliefs

When experts matter: Variations in consensus messaging for vaccine and genetically modified organism safety

Does consensus messaging about contested science issues influence perceptions of consensus and/or personal beliefs? This question remains open, particularly for topics other than climate change and samples outside the United States. In a Spanish national sample (N = 5087), we use preregistered survey experiments to examine differential efficacy of variations in consensus messaging for vaccines and genetically modified organisms. We find that no variation of consensus messaging influences vaccine beliefs. For genetically modified organisms, about which misperceptions are particularly prevalent in our sample, we find that scientific consensus messaging increases perception of consensus and personal belief that genetically modified organisms are safe, and decreases support for a ban. Increasing degree of consensus did not have consistent effects. Although individual differences (e.g. a conspiratorial worldview) predict these genetically modified organism beliefs, they do not undercut consensus message effects. While we observe relatively modest effect sizes, consensus messaging may be able to improve the accuracy of beliefs about some contentious topics.

Scientific-Consensus Communication About Contested Science: A Preregistered Meta-Analysis

Scientific-consensus communication is among the most promising interventions to minimize the gap between experts' and the public's belief in scientific facts. There is, however, discussion about its effectiveness in changing consensus perceptions and beliefs about contested science topics. This preregistered meta-analysis assessed the effects of communicating the existence of scientific consensus on perceived scientific consensus and belief in scientific facts. Combining 43 experiments about climate change, genetically modified food, and vaccination, we found that a single exposure to consensus messaging had a positive effect on perceived scientific consensus (g = 0.55) and on belief in scientific facts (g = 0.12). Consensus communication yielded very similar effects for climate change and genetically modified food, whereas the low number of experiments about vaccination prevented conclusions regarding this topic. Although these effects are small, communicating scientific consensus appears to be an effective way to change factual beliefs about contested science topics.

Heuristic and systematic processing differentially influence the effects of scientific consensus messaging on perceived scientific consensus

This study investigated the impact of scientific consensus messaging on perceived scientific consensus in terms of heuristic and systematic processing. Japanese undergraduates (N = 226) received a message indicating relatively moderate and high levels of scientific consensus on the safety of foods grown with pesticides and genetically modified (GM) foods. Participants in the presentation-style evaluation condition evaluated the style and manner of providing the message and thereby were encouraged to heuristically process information about scientific consensus in the message. Participants in the content evaluation condition evaluated the message content and therefore could process the information systematically. After evaluating the message, participants’ perceptions of scientific consensus improved. The levels of posteriorly perceived scientific consensus were higher for the presentation-style evaluation condition than for the content evaluation condition. Participants’ initial beliefs about the GM-food safety predicted their posterior perceptions of scientific consensus for the content evaluation condition but not for the presentation-style evaluation condition. These results suggest that the heuristic and systematic processing of scientific consensus information differentially influence the impact of scientific consensus messaging.