There is a long line of research demonstrating the effectiveness of using social norm messages for persuasion (Farrow et al., 2017). More recently, research on climate change communication has pointed out the effectiveness of using expert consensus messaging (e.g., “97% of climate scientists believe in the existence of anthropogenic climate change”) to increase support for climate change mitigation policies (van der Linden, 2021). Expert consensus messaging at its core is a type of social norm messaging because it conveys the descriptive norm of what most experts believe or support. Notably, these expert consensus messaging has relied on cognition-based language (e.g., believe, think) to describe consensus. What is less known is the effects of using emotion-based language (e.g., feel hopeful, experience anger) in consensus messaging.

As a primary driver of human behaviors, emotions have been shown in many situations to be a more influential predictor of science-related attitudes and intentions than cognition. Emotion consensus messaging may influence audiences through not only perceived norms but also emotional contagion, a feature that is not shared by cognition-based consensus messaging. It is thus worth investigating the effectiveness of emotion consensus messaging coming from experts. However, a common stereotype of experts or scientists is that they should be objective and show no emotions (or at least no negative emotions) in communicating their work. Therefore, an emotion consensus messaging coming from experts may be perceived as inappropriate despite the powerful impacts of emotions.

In comparison, an emotion consensus messaging coming from the public (e.g., “80% of the public feel angry about climate change inaction”) will likely be more appropriate and thus more influential. Public consensus messaging is another commonly studied social norm messaging when it comes to the effects of exposure to public opinion polls. However, no studies so far have compared the efficacy of using expert vs. public consensus messaging in science communication, let alone differentiating the sub-types of consensus messaging (cognition vs. emotion). This gap in literature should not be simply neglected because of the potential of these messaging strategies to contribute meaningfully to both theory and practice concerning science communication.

An experimental study with a 2 (source of consensus: expert vs. public) x 4 (consensus messaging type: cognition vs. anger vs. hope vs. control) between-subjects factorial design will be conducted to examine these ideas in the U.S. context. The findings of this study will contribute to a better theoretical understanding of the relative efficacy of different consensus messaging for science communication, and help science communication practitioners strategically choose a message design that meets their needs.