Public emotional dynamics in prolonged cyclical crisis events: A longitudinal perspective

• Proposes a temporal framework extending ELM to prolonged cyclical crises. • Reveals dynamic shifts in emotional intensity and communication patterns over time. • Introduces CDI and HDI as aggregate-level indicators to track temporal evolution. • Documents communication evolution from heuristic-oriented to evidence-based patterns. This study examines the temporal dynamics of public emotion and cognition during prolonged cyclical crises, addressing a gap in crisis communication research: how information processing patterns evolve over prolonged crisis periods. Drawing on the Elaboration Likelihood Model and affect heuristic theory, we document systematic evolution from heuristic-oriented to central communication patterns during prolonged cyclical crises. Analyzing 58,326 tweets across six discharge phases of Japan's Fukushima wastewater release (August 2023–June 2024), we employ time series analysis, sentiment analysis, and discourse pattern analysis to track temporal patterns of public engagement. Our analysis reveals three principa l findings. First, emotional intensity follows a power-law decay while emotional structure remains stable–a pattern we term the “emotional imprint effect.” Second, communication patterns systematically shifts from characteristics consistent with peripheral routes (emotion and authority-driven) toward characteristics consistent with central routes (evidence and analysis-driven) as crisis familiarity increases. Third, public discourse evolves from binary opposition to multidimensional evaluation, driven by cognitive complexification, evidence orientation, and responsibility differentiation. To quantify these dynamics, we introduce two indices (the Cognitive Depth Index and Heuristic Dependence Index) that enable temporal tracking of processing routes. These findings extend the ELM's applicability to prolonged crisis contexts and provide practical guidance for developing phased crisis communication strategies that align with evolving public cognition.