Impacts of Exemplification and Efficacy as Characteristics of an Online Weight-Loss Message on Selective Exposure and Subsequent Weight-Loss Behavior

The greatest obstacle for health campaigns is most likely a lack of adequate exposure (Hornik, 2002), as public health messages compete with a flood of alternative messages. In light of America's obesity epidemic, the present work examines message characteristics that may foster exposure to recommendations on healthful weight management. Drawing on social cognitive theory and exemplification theory, the present three-session 2x2 experiment examined impacts of efficacy and exemplification, as characteristics of an online weight-loss message, on selective exposure and change in recommended behavior. Exposure depended on both characteristics, as the exemplar, high-efficacy version resulted in longest and the base-rate, high-efficacy version in shortest exposure, while both low-efficacy versions fell in between. Change in recommended behavior was positive and significantly higher in exemplar message groups than for base-rate version groups, where the change was negative.