The Impact of Source Type and Sponsorship Disclosure on Perceived Credibility and Purchase Intentions
Date of Award
Spring 5-2026
Degree Name
Bachelor of Science (BS)
Advisor(s)
Marina Carnevale
Abstract
The rise of influencer marketing has reshaped how consumers evaluate product endorsements, raising new questions about what qualifies as a credible source in the beauty industry. While board-certified dermatologists offer verified medical expertise, social media influencers cultivate credibility through perceived authenticity and relatability. This study examines how source type (dermatologist vs. influencer) and sponsorship disclosure (sponsored vs. non-sponsored) shape perceived credibility and purchase intention. Using a 2 × 2 between-subjects experimental design, 158 participants evaluated a skincare testimonial across one of four randomly assigned conditions. Perceived expertise, trustworthiness, attractiveness, and purchase intention were measured using Ohanian's (1990) semantic differential scales. Contrary to predictions grounded in persuasion knowledge theory, sponsorship disclosure did not significantly reduce credibility or purchase intention. Source type produced a nuanced pattern of effects: dermatologists were rated as significantly more knowledgeable than influencers, while influencers were rated as significantly more expert overall, suggesting that consumers distinguish technical know-how from lived, practical expertise. Neither advantage translated into higher purchase intent. A marginally significant interaction revealed that sponsorship disclosure eroded influencer attractiveness while leaving dermatologist credibility intact.
Recommended Citation
Kouch, Allie, "The Impact of Source Type and Sponsorship Disclosure on Perceived Credibility and Purchase Intentions" (2026). Gabelli School of Business Honors Thesis Collection. 164.
https://research.library.fordham.edu/gabelli_thesis/164
