Abstract
In the U.S., e-cigarette companies can apply for permission to use reduced or modified risk messages (MRMs) in their marketing materials. Because e-cigarette marketing materials should have a nicotine addictiveness warning, MRMs and a nicotine warning could appear together-resulting in a conflicting message. When reading a conflicting message, individuals assimilate evidence supporting their pre-existing beliefs and eventually develop stronger beliefs, diverging more from those with different pre-existing beliefs (i.e., polarization). This study examined if exposure to e-cigarette MRMs with a nicotine warning polarizes smokers' initially opposing beliefs about the efficacy of switching completely to e-cigarettes in reducing smoking-related risks, and if this polarization depends on individuals' need for closure. An online experiment randomized 761 U.S. adult smokers to either three MRMs with a nicotine warning or three control messages. People reported their perceived efficacy of switching completely to e-cigarettes at pre- and posttest and need for closure at pretest. Linear regression showed no polarization effects. Nonetheless, need for closure and pretest efficacy beliefs influenced message response: MRMs with a nicotine warning only enhanced efficacy beliefs of smokers with low pretest efficacy beliefs and low need for closure. Evaluation of e-cigarette mixed communication should consider individuals' motivational and cognitive differences.