This research explored how we can improve tsunami evacuation behavior,which has been a major social issue since the 2011 Great East Japan Earthquake and Tsunami.We introduce Nige-Tore,a smartphone app for supporting tsunami evacuation drills,which was developed within an interdisciplinary research framework.Nige-Tore serves as an effective interface tool that suc-cessfully visualizes the dynamic interactions between human actions (evacuation behavior) and natural phe-nomena (tsunami behavior).Drill participants can check,on their smartphone,the estimated inundation area of the approaching tsunami,along with their own current evacu-ation trajectory.The results of real-world trials using Nige-Tore show that the app is more powerful than conventional devices and methods that have been used in tsunami evacuation training,such as hazard maps and traditional drills that do not make use of any apps,because Nige-Tore provides an interface that enables commitment and con-tingency thinking—which at first glance appear to repre-sent different orientations—to not only coexist but to synergize.“Commitment” (devotion or involvement)refers to the act of immersing oneself in and viewing as absolute one particular scenario or its potential to be actualized,given conditions in which infinite scenarios may be actualized,depending on the interactions between human systems and natural systems.“Contingency”thinking (an accidental or incidental state) refers to the act of relativizing and separating oneself from any particular scenario or its potential to be actualized,given the same conditions.The synergistic effect of “commitment” and“contingency” thinking also expands people\'s capacity to cope with unexpected and unforeseen events.