The effects of spoiler types on audience immersion: an inter-subject correlation study of heart rate

This study used a between-subjects experimental design to examine how five spoiler conditions, including a complete scene without spoiler, a chaotic scene without spoiler, a video spoiler, a verbal spoiler, and a written spoiler, influenced viewers' narrative engagement, heart rate synchrony measured by inter-subject correlation, and task performance while watching suspenseful film clips. Seventy-six university students were randomly assigned to one of the spoiler groups and viewed clips from the film Revenge. Narrative engagement was assessed using the Narrative Engagement Scale (NES), and ECG signals were recorded to derive heart rate time series for ISC-HR analyses. Key cue search task was indexed by a sticker-counting task during viewing. Results indicated that the video spoiler group showed the most consistent advantages, including higher narrative engagement, more frequent key cue search task, and the highest ISC-HR during the spoiler exposure phase. In contrast, the chaotic scene without spoiler group showed the weakest subjective engagement profile, with differences most evident in comprehension-related engagement and partially attentional focus. ISC-HR varied by spoiler modality primarily during the spoiler exposure phase, with the video spoiler group eliciting the highest synchrony, whereas ISC-HR during movie watching did not show clear group differences. Overall, these findings suggest that spoiler modality and narrative coherence shape viewers' cognitive processing and cue monitoring during film viewing, and that ISC-HR can be used as a complementary physiological indicator to support the interpretation of immersion-related self-reports by indexing shared response dynamics among viewers.