Inequality in urban spaces transcends time and culture, new study reveals

A new study led by researchers from the Max Planck Institute of Geoanthropology (MPI-GEA) reveals a scaling relationship between population size and physical expressions of elite wealth in urban spaces, which may transcend time and culture.

From ancient times to the modern world that we live in today, cities have been centres of both opportunity and inequality. Where earlier this was evident in the size of houses, the grandeur of monuments, and the inscriptions celebrating rulers and elites, today, it is observed in luxury high-rises next to struggling neighbourhoods, and tent cities in the shadows of monumental public buildings.

This raises an important question: Is urban inequality coincidentally common or is it an inevitable part of how cities function? 

Setting out to answer this question, the researchers found striking quantitative similarities between ancient and modern cities when it came to how elite wealth was expressed in urban spaces.

Published in Nature Cities, the study examined ancient Roman and modern-day cities to see how wealth scaled with city size, with the findings indicating that the same scaling relationships that appear to shape modern economic activity – in which cities grow richer and more productive as they get larger – may also shape the way wealth is concentrated at the top. In other words, the processes that make cities wealthy may also often make them unequal.

While the data for Roman cities included the number of monuments and inscriptions dedicating monuments to elite patrons, modern cities were analysed based on the number of very tall buildings and skyscrapers, as well as counts of billionaires per city. Statistical scaling methods were then applied to test for mathematical relationships between city size and indicators of elite wealth.

According to the results, elite wealth increases in a sublinear way as cities grow; essentially, while expressions of elite wealth increase with population size, the growth in elite wealth faces diminishing returns with each increase in city size. 

This process results in slightly fewer increases in elite wealth indicators than the previous increase in city size produced, indicating that the rate of elite wealth accumulation slows as cities continue to grow.

“Our research suggests that inequality isn’t just something unfortunate that commonly happens in cities,” says lead author Christopher Carleton. “It’s something that may grow with them, following predictable scaling patterns. It seems as if inequality isn’t a side-effect of city living under particular cultural or economic conditions; it may be a built-in consequence of urban growth itself.”

However, addressing the problem of inequality may be more complex than changing the tax code or adjusting existing policy, the researchers say, as they continue to seek insights from the past and apply them to modern pressing questions. 

Co-author Patrick Roberts asks, “Do different types of urban planning lead to different expressions of inequality? Are there historical examples where inequality was mitigated while cities continued to thrive and increase overall wealth?” 

Answers to these questions will help scientists and policy makers understand longstanding urban dynamics, develop meaningful interventions to address urban inequality, and navigate a pathway towards a fairer tomorrow.

Main image: © Kévin Deneufchatel, MPG