Where people go shapes urban mixing more than where they live, research finds

For centuries, humanity has flocked to urban centers in search of opportunity, employment and the chance to mingle with a diverse array of individuals. However, the extent to which modern cities foster this kind of social mixing remains a topic of debate, particularly in locales with entrenched ethnic enclaves and suburban sprawl.

A recent study from Northeastern University suggests that while mixing does occur, it is more closely tied to the activities people engage in rather than their residential locales. Lead researcher Esteban Moro, a professor of physics, explained that the majority of interactions individuals experience throughout the day stem from their daily routines rather than where they reside.

Utilizing travel surveys from major global cities like Boston, Chicago, Hong Kong, London and São Paulo, the researchers examined how daily activities influenced social interactions across various demographic backgrounds. The data, collected between 2011 and 2018, involved over 200,000 participants who provided information on their home addresses, income levels and daily routines.

By comparing the diversity of income groups encountered during daily travel to their residential neighborhoods, the researchers found that activities accounted for more than half of the mixing experienced by individuals in all five cities. For example, Chicagoans experienced approximately 12% more mixing during their daily commutes than in their immediate surroundings.

While the type of venue visited can influence the nature of these interactions, public transportation emerged as a significant facilitator of mixing across all cities. In Boston and Chicago, for instance, public transit enabled lower-income residents to access neighborhoods typically off-limits to them, leading to cross-class interactions.

Conversely, in São Paulo, the mixing was more direct due to a more heterogeneous user base on public transit. Interestingly, the study revealed that older adults (ages 55-65) tended to mix less with those from different socioeconomic backgrounds compared to younger groups and even seniors (65+). This finding suggests that retirement, a period often associated with increased social activity, may provide opportunities for more diverse interactions.

The researchers also noted that while age differences in mixing were evident, gender differences were largely absent, with one exception: female caregivers exhibited lower mobility and higher levels of segregation compared to non-caregiving women and men. According to Moro, these insights could guide urban planners in promoting social mixing.

He emphasized that while affordable housing in affluent areas is crucial, policies that encourage diverse experiences—such as promoting visits to underutilized public spaces or community events—could also foster greater mixing. However, social scientist Lily Song cautioned against prioritizing mixing for its own sake, highlighting that such interactions often occur in contexts of inequality—such as service workers serving wealthier patrons or child care arrangements.

Instead, she advocated for creating accessible, affordable and inclusive public amenities that cater to all segments of society, thereby ensuring equitable access to the benefits of urban mixing.