Strategic Use of Negative Emojis in Messaging-Based Interventions for Public Health Communication on Social Media: Mixed Methods Study

Abstract

Abstract Background Despite the growing importance of social media in mobile health (mHealth) communication, we lack a clear understanding of how emotional elements like emojis shape message effectiveness. Furthermore, since emojis are inherently tied to text, their impact may be highly dependent on the relevance and context of the accompanying written content. Objective This study aimed to investigate how the valence of emojis affects the effectiveness of mHealth messages and to determine the role of emoji-text congruence in shaping message outcomes. Methods A mixed-method approach was used, encompassing 3 complementary studies. First, an analysis of real-world health-related tweets (N1=257,648) quantified social media engagement in relation to positive, negative, and absent emojis. Building on these insights, 2 controlled experiments (N2=220; N3=190) further explored how negative emojis influence preventative health behaviors under varying levels of text congruence. Results The automatic content analysis revealed that messages containing negative emojis generated significantly higher social media engagement than those with positive emojis (β=0.24, SE=0.03, t257, 593=9.59; P<.001). Subsequently, experimental findings indicated that negative emojis can effectively promote preventative health behaviors (t218=−4.15; P<.001). However, messages with high negative emoji-text congruence are more persuasive in promoting preventive behavior than those with low congruence (F1, 186=5.46, η2=.028; P<.05), highlighting the complex interplay between emotional signaling and message consistency. Conclusions These findings advance our theoretical understanding of emoji-based health communication and provide practical guidelines for public health organizations seeking to optimize their mHealth messaging strategies. Our results highlight the need for careful consideration of both emotional valence and message coherence when designing health communications in the digital age.