Shaping Perceptions Through Body Representation: The Role of BMI in Virtual Health Counseling Agents
Date of Award
12-2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
School of Computing
Committee Chair/Advisor
Dr. Matias Volonte
Committee Member
Dr. Federico Iuricich
Committee Member
Dr. Carlos Toxtli Hernandez
Abstract
Embodied Conversational Agents (ECAs) offer new opportunities for delivering personalized health education and promoting behavior change through interactive dialogue. While prior research has examined the role of conversational style and relational strategies in virtual health counseling, the influence of an agent’s physical embodiment, particularly body mass index (BMI), remains underexplored. This study investigates how visual cues of body type in an ECA portraying a nurse affect user perceptions of trust, credibility, and motivation to adopt healthier dietary behaviors. A between-subjects experiment was conducted in which participants interacted online with one of three versions of the same virtual nurse “Sara”, whose body type was systematically manipulated to represent underweight, normal, and obese BMI conditions. Dialogue content, prosody, and nonverbal behaviors were held constant across conditions, isolating the visual effect of body morphology. Participants completed pre and post-intervention questionnaires assessing diabetes knowledge, intentions to consume fruits and vegetables, motivation for behavior change, and subjective impressions of the agent. Results indicated significant gains in diabetes knowledge and dietary intentions across all conditions. Behavior change intentions increased significantly only in the underweight condition. Perceptual measures revealed that the normal-weight agent was rated highest in realism, fluidity, and likability, whereas the underweight and obese agents elicited mixed impressions. These findings underscore the importance of visual congruence between an ECA’s appearance and its advisory role in health communication. The study contributes empirical evidence on the intersection of social perception, embodiment, and persuasive digital health design
Recommended Citation
Vankit, Sagar, "Shaping Perceptions Through Body Representation: The Role of BMI in Virtual Health Counseling Agents" (2025). All Theses. 4644.
https://open.clemson.edu/all_theses/4644
Author ORCID Identifier
0009-0004-6730-1606