How the past was NOT different

Abstract: https://journals.sagepub.com/doi/full/10.1177/0042098019873796#abstract

One day in 2011, when I was still a postdoc, I happened to attend a lecture by Geoffrey West, a theoretical physicist at the Santa Fe Institute in New Mexico. Although I had no idea at the time, this talk would become a hinge point in my career. Geoffrey is widely renowned for his work on allometric scaling in biology—the fact that many properties of organisms increase more slowly than their size. More recently, he’s applied similar ideas to cities, and that’s what this talk was about. Toward the end of his talk, after discussing all manner of ways in which the properties of cities change with their size, he finally asked rhetorically “where do all these relationships come from?” I was prepared for an explanation related to finance or markets or democracy or innovation—something that was characteristic of contemporary cities in first-world nations. But to my surprise, his answer was a single word which flashed on screen in his next slide: “Networks!”

His answer really struck me because, as an archaeologist who had (to that point) spent most of his time thinking about the distant past, I had become accustomed to focusing on ways that ancient cities were different from those of today. And of course they were different, in any number of ways. Yet here was someone claiming that some of the strongest empirical regularities in contemporary cities derive from something they might well share with their ancient counterparts.

Geoffrey’s words got me to thinking that, if he was right, urban scaling phenomena should be observable in ancient cities too. That evening, I remembered that on my computer I had some data from 1960s-era surveys in the Valley of Mexico, the heartland of the Aztecs, where archaeologists had systematically estimated the population, area, and volume of civic monuments at every archaeological site they encountered. I analyzed these data the same way that I had seen Geoffrey doing in his talk, and lo and behold, the same patterns were there!

The conversations and meetings that followed led to new collaborations and research support from the James S. McDonnell Foundation. After eight years of exciting work, you can read a summary of our findings in a paper that was published this week in Urban Studies. Our paper shows that scaling phenomena are in fact widespread in urban systems of all times and places; and amazingly, it is not just that they all exhibit scaling relationships, but that these relationships appear consistent and seem to derive from the same basic properties of human networks everywhere. And if you read the paper, you’ll see that there are some areas where archaeological data are actually better suited to studying these phenomena than are contemporary data.

As we’ve recovered from the initial shock of these discoveries, we’ve come to realize that it actually makes sense that a good scientific theory of urbanization should account for patterns in the archaeological record as well as the contemporary world. After all, evolutionary theory in biology applies to the fossil record just as much as it applies to living things today. The barrier to deeper understanding, we think, is that researchers have tended to focus on the city as an object of study, as opposed to urbanization as a process. When the process becomes the focus, one begins to see that a much wider range of evidence is relevant. We hope our paper will stimulate additional thinking and work in this spirit.

Read the accompanying article Settlement scaling theory: Bridging the study of ancient and contemporary urban systems on OnlineFirst.