Study of ancient cities can offer lessons for today

York, England, was founded by the Romans in A.D. 71. At about A.D. 200, the ancient Mesoamerican city of Teotihuacan was the biggest city in the world. And Phoenix was settled in 1867.

What do they all have in common? A lot more than you would think, according to a recent paper authored by two Arizona State University scientists and their colleague.

Modern cities have been quantitatively analyzed for some time. But do those same patterns hold true for ancient cities?

They do.

“I was certainly surprised to find that the same quantitative patterns fit for ancient cities as fit for modern cities,” said ASU archaeologist Mike Smith of the School of Human Evolution and Social Change.

Anyone can pick out the differences between a small Iowa town and Manhattan. There’s generally going to be more crime, more wealthy people and more Thai food in the latter. There will also be more innovation and more patents. All of that is obvious. The difference is there will be more of those things per person in New York.

That was true in an ancient city as well.

“We're trying to figure out what are the limits there?” Smith said. “How are they similar or how are they different?”

There are similarities at very basic levels between ancient and modern cities. The authors used a scaling — a feature of objects or laws that do not change if scales of length, energy or other variables are multiplied by a common factor — framework to analyze 12 examples of ancient cities. They also analyzed 25 modern cities. They found results mostly consistent with past studies.

“How do people interact in the built environment?” Smith said. “When people live in a city and move around in cities, there are certain constraints: You can only travel so far. You have to eat a certain amount of food. There's certain constraints on what people can do in cities. In spite of that, these scaling relationships point out sort of very deep similarities because the way people move around in the city and the implications of their interactions with others, that's what turns out to be almost the same in ancient and modern cities, which is rather remarkable.”

When people interact socially, which they do much more in a dense city, there are benefits. They learn what other people know, and that knowledge spreads among people. They do something with it and it helps them. That’s what generates these greater outputs in bigger cities.

When something is sustainable, it lasts. A city the size of Phoenix would not have been sustainable in ancient times because they would not have been able to get enough food here. That changes the sustainability calculation for cities. Is there something about the way society or its institutions are organized that makes a city more sustainable? Do they do well under an autocratic or democratic society?

“We're saying, well, this is an empirical question — it's worth asking,” Smith said. “There's some basis for suggesting that a city like Rome or ancient Ur, or Teotihuacan, there's some basis for saying those cities might have something to tell us about today. We look at the scale of where you see there are certain fundamental urban things that are common throughout history and around the world.”

Complexity scientists studying urbanism need to take a historical perspective, the authors said.

“Research on modern cities cannot claim to identify broad or universal findings when they ignore several thousand years of urbanism before the modern era,” the authors wrote. “Our finding of similar quantitative patterns between these early systems and city systems today reveals deep similarities of human social behavior over the millennia, leading to the same quantitative patterns.”

Jose Lobo of ASU’s School of Sustainability and Scott Ortman of the Department of Anthropology at the University of Colorado, Boulder co-authored the paper with Smith. It was published in PLOS One.

Top image: Image by Anne Wipf from Pixabay