“I'll buy what she's #wearing”: The roles of envy toward and parasocial interaction with influencers in Instagram celebrity-based brand endorsement and social commerce

Companies increasingly leverage Instagram as a channel for brand management, consumer services, and social commerce. This study addresses the dynamics of interaction among brand-related user-generated contents (UGC) posted on Instagram, social media-based brand communication with Instagram celebrities (parasocial interaction [PSI] and envy), and consumers' characteristics (social comparison tendency, compulsive buying tendency, and materialistic envy). Three between-subjects experiments (Experiment 1: N = 121; Experiment 2: N = 106; Experiment 3: N = 377) were conducted to test the effects of Instagram influencers and their branded-UGC on consumer behavior outcomes. Experiment 1 employed a 3 (branded content type [Instagram influencer's photo type]: selfies vs. photos taken by others vs. group photos) x 2 (gender: female vs. male) factorial design. Experiment 2 employed a 2 (content generator type: Instagram celebrity vs. mainstream celebrity) x 2 (gender: female vs. male) factorial design. Experiment 3 deployed a 2 (branded content type: photos listing products vs. photos showing models) x 2 (content generator type: commercial brand [corporate] vs. Instagram celebrity [human]) factorial design. Experiment 1 indicates Instagram influencers' photo types and gender moderate the effects of envy toward and PSI with them on consumers' intention to buy the products Instagram influencers are wearing. Experiment 2 shows content generator types and gender moderate the effects of envy and PSI on source trustworthiness perception. Experiment 3 demonstrates branded content types and content generator types moderate the effects of consumers' physical appearance social comparison tendency, compulsive buying tendency, and materialistic envy on brand trust. This study makes theoretical contributions to the literature on retailing and consumer services as well as provides managerial implications for Instafamous-based influencer marketing and social commerce in Web 2.0 environments.