Immersion in Online Interaction Rituals: The Paradoxical Role of Time-Synchronized Comments on Video Platforms

Many video platforms promote time-synchronized comments (TSCs), comments overlaid on videos in sync with specific timestamps, to facilitate social interaction and enhance video engagement. Yet TSCs can both enrich viewing experiences and distract viewers, thereby reducing engagement. Because TSCs appear as continuous overlaid streams that offer viewers little control over pacing or selection, their structural features may shape interaction in opposing ways. Drawing on interaction ritual theory, we identify two such features, comment density and word density, and examine their effects on video engagement, together with the moderating roles of content characteristics of both TSCs and videos. We test our framework through a field study using panel data from a leading TSC-enabled platform and a psychophysiological experiment that captures viewers’ real-time attentional, emotional, and behavioral responses. The results show that higher comment density strengthens perceived assembly, mutual focus of attention, and emotional entrainment, thereby increasing engagement. By contrast, greater word density disrupts mutual focus and emotional entrainment, thereby reducing engagement. Emotional entrainment emerges as the central mechanism. We also find that these effects vary with TSC emotional polarization and video genre. In addition, we test a reduced visual overlay design that mitigates the negative effects of TSCs. By clarifying how, when, and why TSCs enhance or disrupt engagement, this study extends understanding of micro-level social interaction in mediated contexts and offers guidance for improving TSC-enabled video experiences.