I
am posting today from beautiful Santa Fe, NM. I am here to attend a meeting of
our working group on settlement scaling in the ancient world. Our article on
scaling at Inka sites was accepted by the Journal of Archaeological Science,
and it was posted online yesterday (Ortman et al. 2016):
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| Mantaro region, Peru |
This
paper is a particularly important step in our long-term objective of exploring
the application of settlement scaling theory in the ancient world. To explain
why, let me step back to 2013, when I first got involved with this project. I
was invited to the Santa Fe Institute in summer 2013 to explore the notion that
urban scaling theory should be applicable to ancient cities. Luis Bettencourt
and Jose Lobo had been working on scaling in contemporary cities for some time,
and Scott Ortman had begun to explore an application to the pre-Spanish Basin
of Mexico. They were interested in how an expert in ancient cities would react
to this research. I knew nothing of scaling when first invited, so I tried to
read up on the topic before my visit to Santa Fe.
It
was fascinating to me that the quantitative expression of many urban attributes
could be predicted by city size in groups or systems of cities in the modern
world. Many key economic features are amplified in urban settings, to a greater
extent in larger than smaller cities. In economic geography, these changes
associated with large cities are called "agglomeration effects." My
reading of economic geography and urban economics in 2013 led me to think that
agglomeration effects and quantitative regularities in contemporary city
systems were due to processes in the contemporary economy. That is, these
regularities were produced by the globalized capitalist economy.
I
went up to the Santa Fe Institute ("SFI") in 2013 ready to argue that
these scaling regularities should NOT apply to ancient cities. Ancient
economies were not capitalist: wage labor was limited or non-existent, land was
not a commodity, and the whole structure and functioning of the economy in
ancient state societies was radically different from the contemporary situation
(the advanced economy of imperial Rome may be a partial exception, though).
"You guys are barking up the wrong tree" was the essence of my
message for the scaling folks at SFI.
Within
a couple of hours of my arrival at SFI, however, Luis, Jose and Scott had
convinced me that the scaling regularities were NOT dependent upon the
capitalist economy. Luis had just published his paper in Science (Bettencourt
2013). This paper presents a quantitative model that predicts, rather
precisely, the scaling regularities observed in city systems today. But the
model is not based on wage labor, firms, private property, industrial
production, or other attributes of the modern capitalist economy. Instead, it
is based on the way individuals move and interact within the confines of the
urban built environment. Networks of individuals, interacting socially and
exchanging information, were the foundation of Luis's model.
If
Luis is correct (and I have since come to accept that he is), then there is no
logical reason why premodern cities should not exhibit the same regularities
found in modern city systems. I found this possibility quite exciting, and
immediately set out to explore it further. This first meeting was on a Monday, and
I was scheduled to give a public lecture at SFI on Tuesday. The theme of that
lecture was the way ancient cities differed form modern cities, and how that
implied urban scaling should not work in the ancient world! I had to scramble
to revise my slides and lecture. That talk was later turned into a paper,
coauthored with Jose, about the similarities and differences between ancient
and modern cities (Smith and Lobo n.d.).
Anyway,
logic suggested that the processes underlying Luis's 2013 model should also
have operated in cities before capitalism. Furthermore, there was no reason why
these processes should not apply to smaller, non-urban settlements. That is,
village systems should exhibit the same scaling regularities. I started working
in two directions to explore the possibility that scaling would apply to
ancient and nonurban systems of settlement. First, I had to convince myself
that this was indeed the case. The scaling framework implies (but evidently
does not require) that in any urban system, people were able to move around
easily, from the countryside into cities, and between cities. Yet many people
in anthropology and history believed that peasants were typically tied to their
fields and did not move as much as people do today. So I looked into the extent
of geographical mobility in the ancient world, and found that movement was more
prevalent and extensive than many had thought. This was published in World
Archaeology (Smith 2014).
A
central concept in the scaling model is the notion that interactions among
individuals, and the exchange of information that takes place, is one of the
driving forces of social and economic change. This idea came out of economics.
But if such interaction is so crucial, then why hadn't I heard about this in
anthropology and sociology? After all, these fields are devoted to the study of
how individuals interact and exchange information. Again, I had to convince
myself that this concept made sense in terms of how anthropologists and
sociologists understand society. I had to make sure this wasn't another case of
economists making up silly things about individuals and their behavior in order
to preserve the purity of their models. Lo and behold, this concept of the
generative role of social interactions is in fact quite common in the other
social sciences. Perhaps it was my own ignorance that had prevented me from
seeing this, or perhaps issues are simply not framed this way in anthropology
and sociology. So I wrote a paper on this, which is now in press in an edited
volume (Smith n.d.). I focused on architectural historian Spiro Kostof's
concept of "energized crowding" in cities as a good label for the
basic processes involved.
So,
I have now convinced myself that the scaling framework fits with what we know
of societies and cities in both ancient times and in the nonwestern world. They
say that converts make the biggest fanatics, so maybe that explains my
excitement about scaling. But my enthusiasm is based to a major extent on the
second direction of my work scaling: the empirical study of quantitative
patterns in ancient settlement systems. This work is truly a group effort. Our
new paper on Andean scaling is a good example.
Since
our first session in 2013, we have been scouring archaeology and history for
datasets that can be used for scaling. The data requirements are actually
somewhat stringent for past urban systems. Even where we have decent population
figures for an urban system, it is hard to measure economic productivity or the
other variables we want to scale against population. We had a couple of working
groups, with colleagues invited to Santa Fe.
Scott
has taken the lead in most of the archaeological cases. Beyond his initial
forays into the Basin of Mexico settlement pattern data (Ortman et al. 2014, 2015),
Scott has found the scaling regularities in a couple of samples of North
American village societies (Ortman and Coffey 2015). He and his students took
the lead with the Andean data in our new paper; I mainly contributed some
contextual and framing information. I made sure we emphasized that the Inca
were one of the few large-scale ancient state societies that did not have
markets, money, or commercial exchange. The fact that we find, again, the same
scaling regularities in a society with a non-commercial economy is simply
astounding; this is one of the major points of significance for the new paper.
My student Rudy Cesaretti was our RA on
this project a year ago, and he took charge of a study of scaling in medieval
European towns (Cesaretti et al. 2015). This is a great dataset with fantastic
results. I wish PLOS-One would get off their duff and complete the review! Rudy
is now working on a paper that uses data from Henry VIII's beard tax to show superlinear scaling! I want to
be a co-author just so I can add "Henry VIII" and "beard
tax" to my CV! I took the lead in applying the scaling methods to the
question of plaza size at Mesoamerican settlements. We included a sample of
Aztec-period sites (Smith 2005), and Alanna Ossa contributed data from her own
research on plazas in the Mixtequilla area of Veracruz (Ossa 2014), and we
found some published data on the Palenque region. When we scaled plaza size
against population, we got statistically regular results, but they don't match
any known scaling coefficient. Oops. What is going on? And now Scott's
post-doc, Jack Hanson, has produced the first scaling paper on Roman cities
(still in preparation, I think).
We
now have a good conceptual foundation, and empirical results supportive of
Luis's scaling model are piling up. We will have a symposium at the 2017
meeting of the Society for American Archaeology. Settlement scaling is
expanding through the historical and archaeological records. Resistance is
futile. I'll bet if we scaled the size and structure of ships like the Borg
collective and the Enterprise against their population, we would not be
surprised by the results.
I
would guess that many people remain dubious about this enterprise.
Personally I am baffled and amazed at our results. Wow, where does all this
cross-cultural and cross-historical regularity come from? As my ASU colleague
Charles Perreault has pointed out, there is nothing in our background in
anthropology that would have predicted these results, or that can explain them. So, go read some of
these works and see for yourself why a growing number of scholars are getting
excited about settlement scaling.
Bettencourt,
Luís M. A.
2013 The Origins of Scaling in Cities. Science 340:
1438-1441.
2015 Population-Area Relationship in Medieval
European Cities. SFI Working Paper, vol. 15-10-036. Santa Fe Institute, Santa
Fe. .
Ortman,
Scott G., Andrew H.F. Cabaniss, Jennie O. Sturm, and Luís M. A. Bettencourt
2014 The Pre-History of Urban Scaling. PLOS-one 9
(2): e87902.
2015 Settlement Scaling and Increasing Returns in an
Ancient Society. Science Advances 1 (1): e1400066.
Ossa,
Alanna
2014 Plazas in Comparative Perspective in
South-Central Veracruz from the Classic to the Postclassic period (A.D. 300-1350).
In Mesoamerican Plazas: Arenas of Community and Power, edited by Kenchiro
Tsukamoto and Takeshi Inomata, pp. 130-146. University of Arizona Press,
Tucson.
Ossa, Alanna, Michael E. Smith, José Lobo, and Scott Ortman (n.d.) The Size of Plazas in Mesoamerican Cities: A Quantitative Analysis and Social Interpretation. (paper under review)
n.d. The Generative Role of Settlement Aggregation
and Urbanization. In Coming Together: Comparative Approaches to Population
Aggregation and Early Urbanization, edited by Attila Gyucha. State University
of New York Press, Albany.
Smith, Michael E. and José Lobo
n.d. Cities
through the Ages: One Thing or Many? (unpublished ms).
