The interplay of places and human social networks

Scientists have long studied the relationship between geography and social structure and for my PhD thesis I would like to address the interplay of places and human social networks. I am in particular interested in how places shape social interactions and how people shape places. I am, however, hardly the first one to ask those questions as researchers have long studied the relationship between space and the social realm and have found various connections between the two. For example, Backstrom et al 1 have found that the probability of friendship with a person decreases with distance. Scellato et al. 6 have studied the properties of location-based social networks and found that about 40% of all links in locationbased social networks are shorter than 100km. Others 5,7 used the social and spatial properties of location-based social networks to propose a link-prediction model. While Brown et al. 2 developed a model for the evolution of city-wide locationbased social networks, it remains unclear whether the qualities of a place itself fosters tie formation, or the fact that friends tend to meet at specific—more “social”— places. Furthermore, Backstrom et al. 1 utilize the relationship between various geographic features and friendship the location of an individual from a sparse set of known user locations using the relationship between geography and friendship. Wang et al. 8 discover that the more similar two individuals are in their mobility the closer they are in the social network. However, the interplay between the pattern of places one visits and network formation is not yet well understood. Last but not least, De Domenico et al 4 have used the mobility data of friends to consequentially improve user movement prediction, while Cho et al. 3 have built a mobility model incorporating both periodic movement of individuals as well as travel due to the social network structure. The exact interplay of the social struc-