Abstract for: Modeling Group-level Behavioral Responses in the COVID-19 Pandemic: The role of coordinated social bubbles

Human behavioral response plays a critical role in the transmission and containment of epidemics. While considerable research has examined the impact of behavioral responses at individual level, coordinated group-level responses have received less attention. This study explores how group-level behavioral dynamics, in the form of early formation of social \textit{bubbles}, contribute to explaining variations in epidemic trajectories among two sets of European countries. To capture these dynamics, we propose an agent-based computational model leveraging cooperative game theory to simulate the formation and transformation of pandemic-related social bubbles. Our model is validated using real-world infection data from the first wave of the COVID-19 pandemic. The results demonstrate that this compact, simple, and computationally efficient model effectively reproduces both epidemic trajectories and ordinal rankings observed in the selected countries. Further validation with mobility data and robustness tests indicates that the proposed framework possesses explanatory power regarding the recovery patterns of social interactions prior to the official lifting of non-pharmaceutical interventions.