Inequality is rising where social network segregation interacts with urban topology

TL;DR

This study reveals that physical urban structures significantly influence social network fragmentation and income inequality, highlighting urban planning as a potential intervention point to reduce social disparities.

Contribution

It demonstrates a strong link between urban topology and social network fragmentation, emphasizing the role of physical barriers and spatial organization in social inequality.

Findings

Social network fragmentation correlates with income inequality in cities.

Physical barriers like rivers and railroads increase social segregation.

Urban spatial organization influences social network structure.

Abstract

Social networks amplify inequalities due to fundamental mechanisms of social tie formation such as homophily and triadic closure. These forces sharpen social segregation reflected in network fragmentation. Yet, little is known about what structural factors facilitate fragmentation. In this paper we use big data from a widely-used online social network to demonstrate that there is a significant relationship between social network fragmentation and income inequality in cities and towns. We find that the organization of the physical urban space has a stronger relationship with fragmentation than unequal access to education, political segregation, or the presence of ethnic and religious minorities. Fragmentation of social networks is significantly higher in towns in which residential neighborhoods are divided by physical barriers such as rivers and railroads and are relatively distant from the center of town. Towns in which amenities are spatially concentrated are also typically more socially segregated. These relationships suggest how urban planning may be a useful point of intervention to mitigate inequalities in the long run.