麻豆淫院

A study combining remote sensing and administrative data finds that since the mid-20th century, large, growing cities have ceased to be centers of upward social and economic mobility.

Cities have been celebrated as places of innovation and social mobility but also as hotspots of inequality and poverty. Dylan Shane Connor and colleagues measured how the size, density, and connectedness of urban areas in an American's birth county predicted their social mobility across the 20th century. The results tell a tale of a waning relationship between urban development and intergenerational mobility. The study is in PNAS Nexus.

In particular, increases in population density between 1920 and 1990 are associated with significant reductions in intergenerational mobility鈥攖he reverse of the pattern seen between 1920 and 1950. The same reversal occurred for the relationship with inequality, which was reduced by urban expansion in the early 20th century and increased by urban expansion in the late 20th century.

Contemporary urban expansion also decreases average social capital, as quantified by indicators of community and civic engagement, membership in local organizations, altruism, and the density of friendship networks. According to the authors, these weakening social links may explain why growing cities are no longer places of special opportunity for all.