We assume that individuals can choose between three types of activities: socially involved, information-gathering, and self-contained activities to understand the status of an emergency, with decreasing externalities from the first to the last. Consumer choice can change according to the risk stage of an emergency: (i) the early stage, where environmental uncertainty is very high and risk information is not sufficiently accumulated; (ii) the acute stage, where severe damage is observed and people are learning about the situation; and (iii) the convalescent stage, where damage lessens and risk information is relatively accumulated.