The Credibility Calculus in Digital Endorsement: Parasocial Proximity, Authenticity Perception, and the Erosion of Traditional Celebrity Influence Among Indian Urban Consumers

Most research on endorsement marketing treats celebrity and influencer endorsement as a straight substitution, with one replacing the other in consumer preference. We argue instead that influencer marketing is reconfiguring the credibility calculus, the process by which consumers decide which endorsers to trust, rather than simply displacing celebrities. Drawing on Social Comparison Theory (Festinger, 1954), the Elaboration Likelihood Model (Petty & Cacioppo, 1986), and Parasocial Relationship Theory (Horton & Wohl, 1956), we show how social media compresses social distance, encourages more effortful processing of endorsement content, and deepens parasocial intimacy between influencers and audiences. We test these ideas with a survey of 100 respondents in urban and semi-urban India, a market underrepresented in existing endorsement research. Influencers outperform celebrities on trust, authenticity, and purchase intention across most product categories, while celebrities hold their own on entertainment value, evidence, we argue, of functional differentiation rather than wholesale displacement. We close by proposing a Dual Endorsement Efficacy Model that captures this division of labour between endorser types.