Causal Language in Health Warning Labels and US Adults' Perception: A Randomized Experiment.

Abstract

<i>Objectives.</i> To examine US adults' reactions to health warnings with strong versus weak causal language.<i>Methods.</i> In 2018, we randomly assigned 1360 US adults to answer an online survey about health warnings for cigarettes, sugar-sweetened beverages, or alcohol. Participants rated 4 warning statements using different causal language variants ("causes," "contributes to," "can contribute to," and "may contribute to") displayed in random arrangement.<i>Results.</i> Most participants (76.3%) selected the warning that used "causes" as the 1 that most discouraged them from wanting to use the product. "Causes" was also selected most often (39.0% of participants) as the warning that participants most supported implementing. By contrast, most (66.1%) chose "may contribute to" as the warning that least discouraged them from wanting to use the product. We found few demographic differences in these patterns.<i>Conclusions.</i> Warnings with stronger causal language are perceived to be effective and are supported by the public.