Cities as social reactors

Fig 1. Inka storehouses

Some traits of cities seem universal, shared by all cities, large and small, past and present. Neighborhood organization is one of these urban universals, something I have talked about in previous posts (here, and here, for example).  See Smith et al. (2015). Other traits seem more limited to only some kinds of cities, or cities in only a few regions or periods. For example, Inka cities were full of standardized stone storage facilities, built and maintained by the state (Figure 1); such storehouses are rare in other cities. Contemporary cities have organized trash pick-up (whether government or privately run), while past cities lacked this institution. One of my reasons for writing this blog is to explore the nature of these similarities and differences among cities across the span of deep history and around the globe.

A number of lines of research now suggest that that the role of cities as “social reactors” may be another urban universal. This means that the presence of greater numbers of people—in larger settlements—leads to more social interactions, which in turn produces social and economic benefits far beyond what smaller settlements can produce. Cities are places where individuals interact socially in all kinds of ways. As the number of people in a city goes up, the number of potential interactions with other people also rises, but it rises much faster than the number of people. The increase is exponential (Figure 2). These interactions have been called "buzz" (Storper and Venables 2004).

Fig 2. Interactions & pop.

A long line of research in the social sciences focuses on the negative consequences of growing city size. More people means more crowding, and crowding in cities can cause stress, both psychological and social. Larger cities have more crime and more poverty. Social relations may be less personal in larger cities, with neighbors less willing to help one another. One intriguing theory, by archaeologist Roland Fletcher (1995), posits thresholds of population size and density that growing settlements cannot cross unless they develop new means of communication and social integration (Figure 3). Otherwise the stresses of living with too many people make life intolerable and settlements will disintegrate or break down.  When early village dwellers figured out how to communicate information with writing, and how to divide their settlements into increasingly specialized spaces and buildings, they could achieve the transition to the first cities, which had more people and denser populations.

 

Fig. 3. Fletcher's book

Growing city size also has its positive consequences. In early times, the most basic attraction of city life was protection. War and violence have been prominent in all eras of history. Once our ancestors adopted agriculture and settled down, the concept of property was born. Property and riches led to crime and warfare. People quickly figured out that there was strength in numbers. Kings and rulers in past times wanted their subjects to move into town. People were easier to tax and control in cities, and their economic activity created growth and prosperity that benefitted the rulers.

Now let's jump to the present. In contemporary cities, urban growth has what economists call “agglomeration effects” (Figure 4). This means that as firms and factories set up in cities, they attract workers and create greater specialization and increased productivity. These in turn generate growth, attracting even more people to cities and creating more output. The spatial concentration of people and firms in cities leads to economies of scale, which pushes urban productivity even higher. Knowledge and skills can be transferred among people, and from one industry to another, because of their concentration in a city.

 

Figure 4.  Agglomeration effects

This picture of agglomeration economies is a pretty standard view of contemporary cities, as seen by urban economists and economic urban geographers. It is easy to see how cities in this sense can be called “social reactors.” They are places where concentrations of people, firms, and institutions create wealth and growth, built on a foundation of the way the people interact with one another. This is definitely the way cities operate within modern capitalist economies. But what about cities before the modern era, before the birth of capitalism? They didn’t have wage labor; workers did not move among firms and industries as they do today; land markets were rudimentary or non-existent; and economies were far less dynamic than they are today.

Were cities in the past also “social reactors”? My answer to this question a few years ago would have been “no.” It seemed to me (and to many urban scholars) that the generative properties of cities—their capacity to grow quickly and expand economically, their ability to create wealth—arose from the capitalist economy. Ancient cities did not have agglomeration economies, and thus their roles as social reactors must have been far less important than today.

But then I started working on urban scaling with three colleagues. The results have been surprising and illuminating to me, and important for a general understanding of urbanism. I’ve blogged a bit about the scaling work previously (an early post, and later), and I will talk about it more in the future. For now, I will say that this research had convinced me that the concept of social reactors definitely applies to ancient cities, and it even applies to large villages and towns. Something fundamental happens when people live together in settlements, and these fundamental processes become stronger as a settlement gets bigger.

Here is a very brief description of three reasons why I changed my mind on ancient cities and settlements as social reactors.

First, the very regular patterns of how urban traits change with city population, as found for contemporary cities, also apply to past cities. These relationships are analyzed with scaling models, and our research group has found that the scaling patterns of modern cities are also present in cities before the modern era.

 

Fig. 5. Mandan village

Second, these scaling relationships are also found in village settlements among tribal peoples (Figure 5). To me, this is an astounding finding. Generative processes that are thought to be “urban” in nature also affect much smaller settlements in societies that lack cities, kings, laws, and social classes. Wow, this is nothing short of incredible.

Third, the explanation for the above reasons comes from Luis Bettencourt’s (2013) formal model of scaling. Rather than tracing the city dynamics that create scaling to agglomeration economies, this model traces them to face-to-face social interaction within a structured built environment. This means that they should be present in historical cities, in ancient cities, and in non-urban village settlements. And they are!

After a few years of working groups and meetings our project now has a name: “The Social Reactors Project: Human Settlement and Networks in History” and a website. We are physicist Luis Bettencourt, economist Jose Lobo, archaeologist Scott Ortman, and me. Our website has just gone live this week! Check it out for our work and papers, and for the names of postdocs and students who are helping.

The idea that face-to-face social interactions (buzz) are crucial to cities and to urban life is nothing new. Here are three quotes from diverse authors:

“The central theme of this book is that cities magnify humanity’s strengths. Our social species’ greatest talent is the ability to learn from each other, and we learn more deeply and thoroughly when we’re face-to-face.”

--Urban economist Edward Glaeser (2011:250).

“Again and again, we find that one key to creating social capital is to build in redundancy of contact. … Common spaces for commonplace encounters are prerequisites for common conversations and common debate.”

-- Political scientist Robert Putnam and Civic leader Lewis Feldstein (Putnam and Feldstein 2003:291).

“Stable physical settings” promote community. “The neighborhood accommodates and facilitates social interaction.”

--Urban planner Sidney Brower (Brower 2011:19)

I believe this notion was also crucial to past communities, a theme I develop in my new book, At Home with the Aztecs: An Archaeologist Uncovers their Daily Life.

The innovation of our scaling research group is to demonstrate, with solid quantitative data, that these face-to-face interactions were not only present and important in the past, but that they also generated change and output in the past, just as they do today. We have a bunch of papers in production and in press, and some published (see the website). The role of cities as social reactors is not just a contemporary phenomenon, an attribute of capitalist economies. Rather, it is a fundamental attribute of human settlements through deep history and across space.

References

Bettencourt, Luís M. A.

2013  The Origins of Scaling in Cities. Science 340: 1438-1441.

Brower, Sidney N.

2011  Neighbors and Neighborhoods: Elements of Successful Community Design. APA Planners Press, Chicago.

Fletcher, Roland

1995  The Limits of Settlement Growth: A Theoretical Outline. Cambridge University Press, New York.

Glaeser, Edward L.

2011  The Triumph of Cities: How our Greatest Invention Makes us Richer, Smarter, Greener, Healthier, and Happier. Penguin, New York.

Putnam, Robert D. and Lewis M. Feldstein

2003  Better Together: Restoring the American Community. Simon and Schuster, New York.

Smith, Michael E., Ashley Engquist, Cinthia Carvajal, Katrina Johnston, Amanda Young, Monica Algara, Yui Kuznetsov, and Bridgette Gilliland

2015  Neighborhood Formation in Semi-UrbanSettlements. Journal of Urbanism 8(2): 173-198.

Storper, Michael and Anthony J. Venables
2004    Buzz: Face-to-Face Contact and the Urban Economy. Journal of Economic Geography 4 (4): 351-370.

Viking houses in Aarhus, Denmark

Model of early Viking Aros

I am in Aarhus, Denmark for a 3-day conference on early cities. Papers are focusing on cities and methods for studying cities, particularly for the Viking era, Medieval Europe, the late Near East, and the East African coast. I had a couple of hours free before the sessions started, so I visited the Viking Museum in downtown Aarhus. This is a gem of a museum that marks the spot where some Viking houses and deposits were excavated several years ago. It is a small self-guided museum in the basement of a modern building.

Reconstructed plank road

Aarhus, called Aros in the Viking era, was an important craft and trading center. The site was fortified, and then the fortifications were expanded by King Harald Bluetooth in the tenth century. I posted about Harald Bluetooth and his planned circular structures previously.  He founded a church, in the plaza here, and eventually the Cathedral was built in its place. Inside the fortification wall ran a plank road. The archaeologists recovered several of the planks intact, and a portion of the plank road is reconstructed in the museum. You can still see the cart tracks in the original boards, and they are shown in the reconstruction.

House outlines drawn on the floor.

Pit house with skeleton, reconstructed

Pit house excavation with skeleton

One of the things I like best about this museum is that the locations of the excavated houses are shown drawn on the floor.  There were several rectangular pit houses here. In one, a skeleton was excavated in the middle of the floor. This find is reconstructed in the museum.

Urban houselot in Viking Aros

The museum has a painted reconstruction of an urban houselot from the Viking period. Notice the yard around the house, something shown in the town model at the top here (Soren Sindbaek, Viking archaeology specialist and co-organizer of the conference, thinks that the houses in the model may be shown with a more regular layout of the town than actually existed). These houses showed evidence of regular domestic activities, as well as several kinds of craft production. People produced craft goods in their homes,; dedicated workshops separate from houses were a later development.

Runestone from Aros

The museum also shows some nice carvings found in Aarhus (although not at this particular excavation). The runestone says, "Toke Smith raised this stone
after Trolle Goodman's son, who gave him gold and redemption." Was old Toke an ancestor of mine? I love these old runestones. I was impressed at the numbers of them spread over the landscape, still standing, when Cindy and I visited Uppsala a few years ago.

Carving of Loki

There is also a small carved stone with an image of the Norse god Loki. Harald Bluetooth introduced Christianity to Denmark, and Viking carving show both indigenous and Christian images and messages.

The Aarhus cathedral

The museum is just across the street from the Aarhus Cathedral. The church has very nice centuries-old paintings preserved, and it is full of large old gravestones. I could not resist taking a photo of a gravestone that must mark the burial of an archaeologist or a bioarchaeologist.

Grave stone in the cathedral

We took a break from the conference sessions today to make a trip down to the Moesgaard Museum, just south of Aarhus. This is a fantastic museum of anthropology and archaeology, focusing on the Danish past.. The building is brand-new, with a large gently sloping roof planted in grass. Kids were sledding down the hill - that is, the roof of the museum - today. The exhibits on the Iron Age, the Viking period, and the bog-people exhibits are first-rate. There are some innovative features in this museum; its well worth a visit .

I have really enjoyed Aarhus: the conference, the museums, and people, and the food. Thank you to the conference organizers, Rubina Raja and Soren Sindbaek. They direct the "Centre for Urban Network Evolutions" at Aarhus University.

The original status symbols of Teotihuacan

Fig. 1. Almenas decorating the roof of the Bird-butterfly palace

This photo of the "Bird-butterfly palace" at Teotihuacan (fig. 1) shows some of the roof ornaments that decorated the building in ancient times. These objects are called "almenas." They were placed at the edge of the roof of houses and temples throughout the ancient city. Back when I wrote my senior honors thesis on Teotihuacan as an undergraduate (Smith 1975), I thought that almenas were status symbols that marked houses of the high and mighty. I didn't have any data to prove or disprove this idea, it is just something that seemed to make sense. When I began looking closely at the site of Teotihuacan again in the past couple of years, I assumed that someone must have figured out how almenas were used, what they stood for, or their overall significance at Teotihuacan. But I was surprised to find that there were no systematic studies of almenas at all. Individual objects were described in art books, and a couple of interesting ones had received attention (for example, there is one with Maya style images. Wow, what was that doing at Teotihuacan??).

Many whole almenas are in museum collections, and quite a few have been published in museum catalogs, art books, and other works on Teotihuacan. I had an anthropology major, Jenny Melgoza, organize images of these objects and work out a typology (fig. 2).

Fig. 2.  Typology of almenas

Some are made of stone, and others are ceramic. Many are stepped, with or without simple decoration. Some types are more complicated, with depictions of animals, gods, and geometric designs. I asked George Cowgill whether the Teotihuacan Mapping Project had included fragments of almenas when they made collections of artifacts from the surface. The answer was yes, but it seems that no one had gotten around to analyzing these things. So when I was at the ASU lab last May, I engaged the help of Teotihuacan archaeologist Clara Paz, and we took a look.

Fig 3. Clara Paz with almenas

There were hundreds of these things! We dumped out the field specimen bags, most dated to 1964. I don't think anyone had looked at these fragments for almost 50 years! We applied the typology to the fragments, and classified over 700 pieces. This was a pretty quick study: classify the piece, record some attributes (ceramic or stone? evidence of paint?), and took some photos. Clara did most of the work. We immediately noticed that type 4, with the fanciest and most complex design, was the most popular type.

Fig. 4. Temple with almenas

But the real secrets of this collection only came out back at Arizona State University, when I matched up the collection numbers with Cowgill's Teotihuacan database. When doing household archaeology -- as opposed to monumental archaeology, focused on big architectural contexts -- the major discoveries typically come long after the fieldwork is done. They come when one has studied the artifacts and looked at their distribution at the site.  (If you want to explore this theme of the nature of discoveries in household archaeology, read my book, At Home with the Aztecs, due out in a couple of months).

Here are a couple of our findings, reported in a paper that was just published in the journal Mexicon (Smith and Paz 2015). First, almenas were recovered from most types of structures at Teotihuacan: houses of different types, temples, platforms, and open spaces. An engraved image of a temple from a pot (Fig. 4) shows almenas on the roof.  Second, and most significant, almenas are found more commonly on houses of high status than low status. This table (Fig. 5) shows the data.

Fig. 5. Frequency of almenas on different types of structure

Members of the Teotihuacan Mapping Project divided the houses of Teotihuacan into these three categories. Most of the apartment compounds at the site are of intermediate status. Compounds that were larger or fancier than most were classified as high status. And small houses built of perishable materials are the low-status residences. As you climb the status hierarchy, an increasing proportion of the houses had almenas. This finding supports my old undergraduate hypothesis that these were status symbols. But the picture is complicated. Even the lowest status houses could have an almena or two. And temples also had these things. Want to know more? You can read the article (in Spanish) here.

Fig. 6.  Three almenas in the sculpture garden at Teotihuacan

What's next? There is still more to do with these several hundred almena fragments from the Teotihuacan Mapping Project. With more time and more student help, I want to study these things in greater detail, to learn more about their forms and materials. And the whole almenas in museum collections and publications can yield more information if analyzed systematically.

This was just a small study of a small collection of artifacts, but it illustrates some important points.

1. First, artifacts can yield new insights many years after excavation, IF they are properly stored and cataloged. This is one of the reasons for the existence of the ASU Teotihuacan Research Laboratory.
2. Second, fragmentary artifacts are often more informative than whole objects, particularly when the fragments have good contextual information and the whole ones lack such information.
3. Third, quantification of artifacts is the key to unlock their potential information about the nature of past life and society.

And finally, check out the almena now embedded in one of the local churches near Teotihuacan (Fig. 7).

Fig. 7. Almena in the wall of a church (arrow)

REFERENCES:

Smith, Michael E.
1975    Temples, Residences, and Artifacts at Classic Teotihuacan. Senior Honors Thesis, Department of Anthropology, Brandeis University.

Smith, Michael E. and Clara Paz Bautista2015    Las almenas en la ciudad antigua de Teotihuacan. Mexicon 37 (5): 118-125.

Unsung heroes in the distant past

unsung hero (n) : one who created positive change in history by improving the lives of others, and has yet to be recognized for his or her actions.

I have been wondering lately whether the phrase "unsung heroes" might be appropriate to describe the common people of the distant past. They were important for posterity, yet we don't know their names and they rarely get much credit. Historians long concentrated on kings, generals, and other important people, while archaeologists focused on tombs, temples, palaces, and pyramids. But with the development of the fields of "social history" and "household archaeology," those of us who work on the past now have methods and concepts to study  the lives of everyday people. Farmers, weavers, merchants, soldiers, builders, midwives, shopkeepers, bureaucrats -- all the people who kept society going in the distant past.

Most of my career has been dedicated to excavating the places where the Aztec common people lived and worked, and to the reconstruction of their lives and the wider society of which they were part. After decades of writing technical articles and reports (and a textbook), I decided a few years ago to try and make sense of my excavations in a way that people who are not archaeologists could understand and appreciate. I initially thought this would just involve writing in clear prose, but a writing coach and my agent convinced me that I really needed to restructure the way I write. And my rewriting and restructuring led me to re-think the story of the Aztec farmers whose lives I was reconstructing.

Aztec women making tortillas. Drawing by Kagan McLeod.

A visit to the Lowell Milken Center for Unsung Heroes in Fort Scott, Kansas, got me thinking about this concept of unsung heroes. My daughter Heather is the Director of Economic Development for the City of Fort Scott, and during a visit she took Cindy and me to the Milken Center. This is a fascinating and unique educational resource center and museum. It got its start after a National History Day project led by local high school teacher, Norm Conard, uncovered the life of Irene Sendler. Sendler, a Catholic, was a Polish social worker who saved several thousand Jewish children from the Warsaw Ghetto in World War II. Her story was almost unknown until it was discovered and documented by three Kansas high school kids working on a project with Norm. The excellent and moving book, Life in a Jar: The Irene Sendler Project, by Jack Mayer, tells the story of the Kansas project, as well as Irene Sendler's life and activities (this is a great read!).


Norm Conard won a teaching award from by the Milken Family Foundation, and conversations between Norm and Lowell Milken led to the establishment of the Lowell Milken Center for Unsung Heroes in Fort Scott. The center has exhibits on the lives of Irene Sendler and many other unsung heroes, all documented by students' history projects. The center offers fellowships, grants, and workshops for teachers and students, and promotes the study of unsung heroes. Here is their definition (from the Center's website):

unsung hero (n) : one who created positive change in history by improving the lives of others, and has yet to be recognized for his or her actions

This concept, which focuses on identifiable people form the recent past, does not precisely describe the common people of antiquity. But the idea got me thinking about those Aztec farmers in a new way, as unsung heroes of a different kind. Here is a passage from my book (At Home with the Aztecs: An Archaeologist Uncovers their Daily Life, due in early 2016):

Aztec commoners were the people who carried ancient Mesoamerican cultural traditions into the Spanish colonial period, and their descendants transmitted this tradition through the subsequent centuries. When we order tacos and beans at a Mexican restaurant today, we can thank Aztec peasants more than their noble overlords. The basic elements of Mesoamerican cuisine (and many other traits, from language to myth to house construction) have been preserved across the Spanish conquest only because the peasants continued their traditional lives and practices. Their noble overlords, in contrast, did everything they could to act like Spaniards, from eating wheat bread to speaking Spanish to riding horses. Aztec farmers and other commoners are the unsung heroes of their culture, the ones responsible for carrying it into the Spanish colonial period and on up to the present.  (chapter 1)

Lowell Milken, Norm Conard, and staff at the Center

But I think the usefulness of the unsung heroes concept goes farther than this. My Aztec peasants, for example, were heroes not just for preserving the Mesoamerican cultural past, but for doing the work to build and support their communities and their society. While they had to obey kings, contribute labor to state projects, and pay rent to noble landlords, these ancient farmers had a fair degree of autonomy and self-determination in their lives. If we find value in the Aztec or Mesoamerican past today--and I think we can--I would attribute this less to the kings and nobles and more to the common people. These were the true unsung heroes of the distant past.

(note: What got me thinking about all this tonight was a request for an interview from a student doing a National History Day project!).

Religion and early cities in Mesoamerica

When you hear "religion" and "early cities" in the title of a work, watch out! Chances are, you are about to read a speculative account about the mystical symbolism of ancient cities. This is a popular topic in some circles. The basic argument is that all ancient cities were highly sacred places, and that this religious symbolism was the reason people moved into cities. Religion shaped peoples' lives, perhaps even more than everyday activities. At its most extreme, this reasoning slips into the silly notion that ancient people worried about death and the afterlife more than they thought about their daily life. Egypt is the most common target of this silliness, although the Classic Maya and other ancient societies have also been implicated. Give me a break! Ancient peoples were no more obsessed with death and the afterlife than you or I.

Now, there is a more respectable line of thought on ancient religious symbolism and cities, but it too is often slips into speculation and even nonsense. Associated with the historian of religion Mircea Eliade, it goes like this. Ancient peoples believed that life on earth was a direct parallel of the cosmos. When cities were built, especially political capitals, they were more successful if they were planned and laid out as models of the cosmos. Since the cosmos are laid out in a four-directional plan (north-east-south-west, with a center point), then cities should follow an orthogonal layout, with a center point where the north-south and east-west axes met. This model does fit some early urban traditions--most notably in China, India, and
Southeast Asia. For early cities in these regions, we have written texts and images that clearly illustrate how cities and buildings were laid out to mimic the organization of the cosmos. Such cities and buildings are often called "cosmograms."

The idealized Chinese city above was a kind of cosmogram, but the Aztec city next to it (actually the sacred precinct of Tenochtitlan) was NOT a cosmogram. How do we know? Because we have written and pictorial records that describe the symbolism of the Chinese city, how it was laid out in imitation of the cosmos, and how emperors picked the sacred place to build their new capital city (see below).

For some reason I have yet to figure out, this idea of cosmograms has been so attractive to some scholars that they go out of their way to find cosmograms all over the place. For China or India, this is fine. But when they start talking about cosmograms in ancient Mesoamerica, they are arguing more from personal bias than from evidence. There are NO WRITTEN RECORDS claiming that Aztec or Maya cities, for example, were cosmograms. But that hasn't stopped these scholars from claiming to have found cosmograms. If you haven't guessed, this kind of speculation dolled up as scholarship drives me up the wall. Ten yeas ago I published two critiques of this kind of reasoning (Smith 2003, 2005), but it still persists in some quarters.

So perhaps I can be excused if I got worried at the title of a new book from David Carballo of Boston University: Urbanization and Religion in Ancient Central Mexico. Would this be the same old kind of speculative account, claiming that ancient people went around pondering the mystical symbolism of their cities? Thankfully, the answer is NO. Carballo finds ways to address the relationship between cities and religion that is based on evidence, and uses contemporary social concepts such as collective action theory rather than the worn-out universal claims of Eliade and his followers.

Rather than worrying too much over the content of religious symbolism, Carballo looks at rituals: actions that people carried out in specific places, that left material traces:

I am less interested in attempting to define religion in an overarching sense and more interested in examining what religion did and the spatiality and temporality of its performance, within the context of urbanization.   (p. 19)

Hear, hear, this is the kind of approach we need more of in Mesoamerican archaeology. For Carballo, ceremonies in formal plazas generated social cohesion in urban populations, contributing to the success of urban life in the centuries leading up to the great Classic-period urban center of Teotihuacan. Carballo does not ignore the content of ancient religious ideas, and his discussion is reasoned and evidence-based:

Issues of greatest collective concern -- such as creation, existential dualisms, and fertility cycles -- fostered cohesion and, in continuing to feature prominently in indigenous religion, have proved the most resilient. In contrast, group divisions along the lines of lineage, status, and community were fostered through other means and saw much greater turnover through time.  (p. 201)

This is an excellent book, and I recommend it for anyone interested in the Mesoamerican past and anyone interested in new ways to look at how religion and urbanization were intertwined in the early states.

Carballo, David M.
2015    Urbanization and Religion in Ancient Central Mexico. Oxford University Press, New York.

Smith, Michael E.
2003    Can We Read Cosmology in Ancient Maya City Plans? Comment on Ashmore and Sabloff. Latin American Antiquity 14: 221-228.

2005    Did the Maya Build Architectural Cosmograms? Latin American Antiquity 16: 217-224.