This study challenges the long-held belief that large cities promote socioeconomic mixing. Using mobile phone data representing 1.6 billion real-world exposures among 9.6 million individuals in the US, researchers found that exposure segregation is significantly higher in large metropolitan areas. This increased segregation is attributed to the availability of differentiated spaces catering to specific socioeconomic groups in large cities. However, the study also suggests that strategically positioning city hubs can mitigate this effect by bridging diverse neighborhoods and facilitating encounters among individuals of different socioeconomic statuses.

Hamed Nilforoshan, Wenli Looi, Emma Pierson, Blanca Villanueva, Nic Fishman, Yiling Chen, John Sholar, Beth Redbird, David Grusky, Jure Leskovec