Dr. LEE Ka Lai, DanielleDanielleDr. LEE Ka LaiBorah, PorismitaPorismitaBorah2026-08-062026-08-062026Lee, K. L., & Borah, P. (8 Aug 2026). Healthcare advertising: The roles of narrative and audiovisual effects. Annual Conference of American Psychological Association (APA) 2026, online.http://hdl.handle.net/20.500.11861/28413Introduction. This experimental study investigates the concurrent effects of a content feature (narrative vs. non-narrative) and a media feature (presence vs. absence of audiovisual effects) on user engagement and message endorsement in the context of influenza vaccination promotion on YouTube. This study tests how these features influence various dimensions of engagement and endorsement (self-efficacy), drawing on Construal Level Theory (Trope & Liberman, 2010). Methods. A 2 (narrative vs. non-narrative) × 2 (presence vs. absence of audiovisual effects) between-subjects experimental design was implemented with a sample of 380 participants (Age mean= 38.74 years, SD= 12.30; 53.62% male (n= 200), 45.53% female (n= 173)) recruited via MTurk. Participants were randomly assigned to view one of eight professionally produced vlogs promoting influenza vaccination that systematically varied in content style and media features, after which they completed measures assessing multiple dimensions of narrative engagement and self-efficacy as an indicator of message endorsement. Results. Results demonstrated that narrative format significantly enhanced viewer engagement, evidenced by stronger identification (b= -0.29, p< .05), greater sense of presence (b= -0.29, p< .05), and more intense emotional responses (b= -0.31, p< .05) compared to non-narrative format, while audiovisual effects generally boosted identification and presence across content types; however, a significant interaction for message endorsement, F(1, 291)= 9.40, p< .05, η²= 0.03, revealed that self-efficacy was maximized through feature congruence—narrative with audiovisual effects (M= 1.22) and non-narrative without them (M= 1.23). Discussion. This study demonstrated that user engagement does not automatically lead to message endorsement. They are driven by different feature combinations. Achieving endorsement requires a strategic match between the content’s construal level and the media features used while audiovisual effects can universally enhance feelings of engagement. Findings offer crucial implications for health communicators which could suggest that message design should be aligned with specific campaign goals.enConference Paper