Slight vs. broad smiles? The effects of virtual influencer smile intensity on ad attitude

Purpose Despite the growing use of virtual influencers (VIs) in social commerce, little is known about how their emotional expressions—specifically smile intensity—affect audience responses. This research examined the effects of varying smile intensity on ad attitude and explored their underlying psychological mechanisms through anthropomorphism and expression authenticity. The moderating role of virtual influencer type (realistic-style vs. anime-style) was also investigated. Design/methodology/approach Three experiments were conducted: a 2 (influencer type: human vs. virtual) × 3 (smile intensity: neutral expression vs. slight smile vs. broad smile) between-subjects design, a three-condition (smile intensity: neutral expression vs. slight smile vs. broad smile) between-subjects design, and a 2 (virtual influencer type: realistic-style vs. anime-style) × 3 (smile intensity: neutral expression vs. slight smile vs. broad smile) between-subjects design. Findings Across three studies, we found that a virtual influencer's smile (slight or broad) elicited a more favorable ad attitude than neutral expressions. Counterintuitively, we also found that slight smiles outperformed broad smiles (Study 1). Smiling, in general, improved attitudes through increased anthropomorphism, although broad smiles simultaneously diminished expression authenticity and subsequent ad attitude (Study 2). Lastly, we found that the mediation effect of expression authenticity is significant for realistic-style VIs but absent for anime-style VIs (Study 3). Originality/value Adding to the literature on virtual influencers and emotional expression, this research reveals a critical and previously unexplored difference in the effects of smile intensity on attitudes between human and virtual influencers. Notably, this research indicates that increased smile intensity does not always translate to a better outcome—it could backfire when expression authenticity is diminished. This provides vital insights for designing effective virtual influencer campaigns in social commerce.