Universal spatial inflation of human mobility

Understanding the interplay between egocentric preference and urban structure in shaping human mobility has profound implications for improving epidemic intervention, social equity, and urban resilience. However, numerous existing studies either solely identify the egocentric preferences -- the anchoring effects from home -- or the impact of hierarchical urban structures. Here, we propose a network-based approach to present human mobility in both spatial and topological aspects within the urban system, using cell phone trajectory data from millions of users across three countries. By segmenting mobility trajectories into modules and examining their overlap with urban scales, we have observed the inflation law that the geospatial extent of these modules increases sub-linearly with their distance from home. Moreover, the egocentric preference for higher urban levels leads to this increase. This universal finding indicates that home-based preferences distort the hierarchical scales of human mobility in the urban environment, regardless of demographics or geography.