The Influence of Presumed Social Media Influence: Longitudinal Analysis of Exposure to Alcohol-Related TikTok Content and Social Norm Perceptions

= 883). We found that between-person covariances and cross-sectional correlations support the proposed mechanism of influence of presumed social media influence (IPSMI). However, there is no evidence of a longitudinal within-person influence of exposure to alcohol-related TikTok content on perceived descriptive or injunctive social norms regarding alcohol. These findings question causal interpretations commonly proposed in the literature and highlight a need for theoretical refinement and further empirical exploration of temporal dynamics of presumed media influence and norm formation.