A Multimodal Discourse Analysis of Health Communication Posters: A Case Study of U.S. Educational Institutions During the COVID-19 Pandemic

การวิเคราะห์วาทกรรมหลากรูปแบบในโปสเตอร์การสื่อสารด้านสุขภาพ: กรณีศึกษาสถาบันการศึกษาในสหรัฐอเมริกาในช่วงการแพร่ระบาดของโควิด-19

Abstract

The COVID-19 pandemic highlighted the need for effective health communication strategies, particularly within educational institutions. This study investigates how U.S. universities employed multimodal discourse in face-mask promotion posters to encourage preventive behaviors. Using Multimodal Discourse Analysis (MDA), the research examines verbal elements through advertising language features and commodity exchange theory, and visual elements through social semiotic frameworks. A mixed-methods approach combined qualitative analysis of semiotic strategies with quantitative frequency analysis to determine their prevalence. Findings reveal a predominant use of imperative language (90%) and phonological repetition, including alliteration (80%) and assonance (80%), to enhance memorability. Symbolism was universal (100%), with the mask serving as a central metaphor for protection and responsibility. Compositional techniques such as size prominence (90%) and color contrast (70%) heightened message visibility, while alignment between verbal and visual modes strengthened engagement and persuasion. Despite these strengths, most posters lacked cultural and linguistic diversity. The study contributes to digital health communication research by demonstrating how multimodal strategies reinforce public health messaging and by emphasizing the importance of culturally responsive and visually inclusive communication during health crises.