Whose Message Is More Powerful? Comparing the Effect of Virtual Influencers and Human Celebrities on Social Media Persuasion Depending on Perceived Source Characteristics and Nutrition of Instagram Food Messages

This study explores how endorser type affects attitudes and behavioral outcomes of social media users based on the Source Models, the dual processing model, and celebrity endorsement. The findings introduce a new type of social media endorser and propose a mechanism of virtual influencer endorsement compared with human celebrity endorsement. In detail, my research initially found that perceived source features mediate the association between endorser type (virtual influencer vs. human celebrity) and message persuasion (attitude toward the post, viral behavioral intention, and intention to consume the food in the post). For mediation models, the effects of human celebrities are more powerful with stronger perceptions of source attributions (trustworthiness, attractiveness, likeability, similarity, and parasocial interaction, but not expertise) than those of virtual influencers. Next, this research revealed a moderated mediation model showing that virtual influencer-endorsed Instagram posts generate a more favorable attitude toward the post depending on food type (energy-dense nutrient-poor foods vs. preferred foods) through likeability, but only for Instagram posts featuring energy-dense nutrient-poor foods (EDNP foods). Overall, the findings show that additional factors besides endorser type influence message elaboration and are the key elements to explain how virtual influencers form positive attitudes from target audiences with perceived source features in the dual processing model. This study provides theoretical contributions and practical implications by applying classical literature to a new media context.