How do individuals resolve conflicts over resources? One way is to share resources, which is possible between known individuals, with the use of sanctions on free riders or by partner selection. Another way is for anonymous individuals to respect the finders' ownership of resources based on asymmetry and avoid conflicts over resources. This study elucidates the conditions under which anonymous individuals share resources with each other irrespective of their asymmetry with regard to resources. High resource values inhibit anonymous individuals from sharing resources; however, small cumulative values and local distributions let anonymous individuals share the resources. Punishment of the richest individuals also supports resource sharing. These conditions may represent resource sharing among anonymous individuals in periods of great disasters and may be the origin of the practice of exchange in prehistoric times.

For rural revitalization, universities in Japan encourage students to nurture relationships with partner organizations in rural areas. Fieldwork studies are one of the prominent methods for rural revitalization. However, students in urban universities should less likely maintain such relationships in rural areas even if they undertake fieldwork studies. The present study illustrated how students and graduates had relationship with rural areas after the fieldwork studies. The author contacted with three professors in an urban university who implemented advanced fieldwork studies in five rural municipalities of Kinki region, Japan. The author asked the three professors about excellent graduates and students who had undertaken fieldwork studies, in total 16 individual. The author interviewed these students for their experiences and growth through the fieldwork studies. As a result, 11 of 16 interviewees lived and worked in urban areas. However, students from urban hometowns became interested in revitalizing rural areas through their jobs, whereas those from rural hometowns were motivated to return in the future. After fieldwork studies, students determined the strengths and weaknesses of rural areas compared with those of urban areas, which could contribute to future rural revitalization through their jobs. For rural revitalization in the future, collaboration between urban universities and rural areas are recommended.

In Japan, the overall population is declining. Depopulation is severe, resulting in various negative consequences, particularly in rural areas. Rural communities could benefit by collaborating with people from other places, mainly urban areas. Typical examples of visitors or tourists from urban areas in these cases are referred to as “kankei jinko.” The more fundamental issue, however, is that many rural residents have lost confidence in their ability to live in areas with declining and aging populations. It is important to note the potential for highly mobile people from urban areas to increase the civic pride of rural residents. This raises questions about who these nomadic people, or “affiliative nomads,” are and how they interact with residents. To answer these questions, we analyzed cases of affiliative nomads in previous studies. The nomadic people showed respect for the rural areas to the residents; as a result, they were perceived by the residents as being in a stage of growth. When the nomads and residents interact, they create common values such as nature conservation and economic and community revitalization. Thus, the nomads cultivate civic pride among the residents and could be regarded as affiliative nomads. Furthermore, some coordinators bridge residents and nomads to expand their relationships with other people. Affiliative nomads may be sustainable tourism stakeholders and contribute to solving the problems of depopulated areas in Japan and other developed or emerging countries.

High mobility has promoted the concentration of people’s aggregation in urban areas. As people pursue areas with higher density, gentrification and sprawl become more serious. Disadvantaged people are then pushed out of urban centers. Conversely, as mobility increases, the disadvantaged may also migrate in pursuit of their desired density. As a result, disparities relative to density and housing may shrink. Hence, migration is a complex system. Understanding the effects of migration on disparities intuitively is difficult. This study explored the effects of mobility on disparity using an agent-based model of opinion formation. We find that as mobility increases, disparities between agents in density and diversity widen, but as mobility increases further, the disparities shrink, and then widen again. Our results present possibilities for a just city in the age of mobility.