Sit is not lit: Examining the impact of message framing, modality, and peer influence on attitudes and intentions to reduce sedentary behavior

This study examines the effects of gain-loss framing, messaging modality, peer influence, and individual factors such as social norms and self-efficacy on the attitudes and intentions to reduce sedentary behaviors among university students, specifically through (a) taking breaks and (b) taking 10,000 steps daily. We conducted a two-week health campaign field experiment on Instagram in January 2022, delivering ten posts with tailored messages to 284 university students in Singapore (valid N = 249). The participants were predominantly female (70.16%), ages 21–34 years (M = 24.2, SD = 3.19). This study measured attitudes and intentions to take breaks and 10,000 steps daily as key outcomes. The study yielded three key findings: (1) Gain-loss framing effects were amplified by peer influence, descriptive norms, and injunctive norms, with peer influence amplifying loss framing and both norms amplifying gain framing; (2) Gain framing was more effective than loss framing for motivating the intention to take 10,000 steps; (3) Injunctive norms were associated with attitudes and intentions to take breaks and the intention to take 10,000 steps, while self-efficacy was associated with attitudes toward taking breaks and both attitudes and intentions to take 10,000 steps. This study contributes theoretically by demonstrating how social dynamics amplify framing effects, with peer influence enhancing loss framing on attitude towards taking breaks and norms strengthening gain framing on attitude and intention towards taking 10,000 steps. Practically, it suggests health campaigns can effectively promote behaviors like taking breaks or walking by leveraging norms, peer influence, and self-efficacy. © 2025 Elsevier Ltd.