Vulnerability and the computational logic of fear: insights from the horror genre

Why are people drawn to stories that evoke fear? The paradox of horror, which refers to our fascination with frightening narratives despite their negative emotional content, has received a compelling explanation from evolutionary science: humans are attuned to threat-related information because it carries adaptive value. In this work, we extended that framework by identifying a key structural condition that elicits fear in fiction: protagonist vulnerability. We introduced the Protagonist Vulnerability Index (PVI), a computational measure of the formidability imbalance between protagonists and antagonists, and applied it to 691 films. We showed that horror films systematically feature weaker protagonists, stronger antagonists, more persistent threats, and more hostile environments. We also demonstrated that PVI reliably distinguishes horror from other genres, predicts fear-related keywords in non-horror films, and correlates with physiological fear responses as measured by heart rate. By linking PVI scores to psychological and demographic data from more than 3.5 million individuals on Facebook, we found that a preference for high-PVI films is associated with lower agreeableness, conscientiousness, and extraversion, and with higher openness. We also found that openness moderates the negative association between neuroticism and fear-related content, suggesting that curiosity can override threat avoidance in anxious individuals. These findings clarify the narrative conditions that activate evolved threat-management systems and provide a framework for predicting and potentially engineering fear in fiction.