Theses and Dissertations

Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Dr. Reto Felix

Second Advisor

Dr. Deniz Atik

Third Advisor

Dr. Mohammadali Zolfagharian


Drawing on the notion of parasocial interaction (PSI) theory (Horton and Wohl, 1956), this dissertation provides a framework to demonstrate how YouTube health vloggers can influence viewer compliance intention toward a prescribed health behavior (i.e., weight-loss diet to lose weight). Initially, drawing on the discounting principles of attribution theory (Kelly, 1973), physical attractiveness stereotype (Eagly et al., 1991), and the black sheep effect (Marques and Yzerbyt, 1988), the interaction effects of three vlogger characteristics on viewer PSI experience were conceptualized and examined (Study 1). Then by using a scenario-based experiment, viewer PSI experience with the vlogger was manipulated (high vs. low) and drawing on social comparison theory (Festinger, 1954), PSI’s effect on the core dependent variable of this research, compliance intention was tested. In the process, this research also accounted for the mediating role of viewer readiness (role clarity, ability, and motivation), the moderating and the mediated moderating role of viewer health consciousness through viewer readiness in the PSI—compliance intention relationship. Overall, results indicated the dominance of vloggers’ credibility over the other two vlogger characteristics—physical attractiveness and ethnic similarity in engendering PSI experience with the viewers. While no main or interaction effects of vloggers’ physical attractiveness and ethnic similarity were found in generating viewers’ PSI experience with vloggers. The positive influence of PSI on compliance intention was found both as a direct effect and also through the mediating role of viewer readiness. While viewer health consciousness is found to have no moderating influence in the PSI—compliance relationship both in the direct effect and also in the indirect effect mediated through viewer readiness. The findings and their implications are discussed.


Copyright 2020 by Md. Nazmus Sakib. All Rights Reserved.

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