Abstract
INTRODUCTION: Social media platforms provide constant, quantifiable feedback that can shape self-esteem, particularly during adolescence, a period of heightened neurobiological sensitivity to social evaluation. While previous research has examined digital feedback effects on well-being, comparative evidence on adolescents and adults remains limited. This study investigated how feedback valence, social comparison, and perceived authenticity influence state self-esteem across these developmental groups. METHODS: A cross-sectional, quasi-experimental design was employed with 240 urban Chinese participants (120 adolescents aged 13-18 years and 120 adults aged 25-40 years). Participants were randomly assigned to positive, neutral, or negative feedback conditions within a simulated social media environment. State self-esteem was assessed using the State Self-Esteem Scale, with social comparison orientation and perceived authenticity measured as potential mediating and moderating factors. Data were analyzed using ANOVA, mediation, and moderation models with covariate controls. RESULTS: Adolescents demonstrated significantly greater sensitivity to feedback than adults, with larger increases in self-esteem after positive feedback and sharper decreases after negative feedback (Age × Valence interaction, F(2,234) = 6.65, p = 0.002). Main effects of feedback valence were observed across both groups (F(2,237) = 10.85, p < 0.001). Mediation analyses indicated that social comparison orientation partially accounted for the relationship between feedback valence and self-esteem, while moderation analyses revealed that perceived authenticity buffered against the negative effects of unfavorable feedback. All five preregistered hypotheses were supported. DISCUSSION: Findings highlight adolescence as a developmental stage of heightened vulnerability to digital evaluation, reflecting neurocognitive imbalance between socio-affective reactivity and regulatory control. Social comparison emerged as a mechanism that amplifies feedback effects, whereas authenticity functioned as a protective factor across all ages. These results refine theoretical models of digital self-esteem regulation and suggest targeted interventions for adolescents, including digital literacy curricula, resilience-building, and platform design modifications to mitigate comparison pressures.