Tuesday, August 9, 2016

My journey in settlement scaling

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):
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.

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).

Monday, July 4, 2016

How do neighborhoods form?

Neighborhood organization is one of the few universals of urban structure. All cities, past and present, all over the world, are organized into neighborhoods. Sometimes neighborhoods are planned from the start by officials or commercial builders. Think of all the ready-made suburban neighborhoods built by developers today, with their phony bucolic- or English-sounding names. Or consider company towns, whether ancient Egyptian workers settlements or capitalist factory cities like Pullman, Illinois. The planners build in neighborhoods from the get-go. If they aren't planned out in advance, however, neighborhoods spring up on their own. People interact with those living nearby, new residents move into areas where they know people, or where people are like them culturally, and before long there are neighborhoods that are clear to residents and visitors alike.
Neighborhoods: suburban U.S., Ottoman city; Chinese city

One of the best ways to look at certain urban processes, to my mind, is to examine "semi-urban" places. These are places where large numbers of people gather together, often on a temporary basis. They aren't really cities--they aren't permanent enough. After a while, people leave and go home. But when people gather in  one place, a certain "energized crowding" takes place (see my post on Cities as  Social Reactors), and by looking at what happens, we gain a better understanding of urban processes and activities.

So, here I want to take a quick look at three very different kinds of semi-urban settlements (a company town, a protest camp, and the Burning Man festival) to see how neighborhoods develop. This post is based on a recent article (Smith et al. 2015) that looks at neighborhoods in a wider range of semi-urban settlements. I won't cite a bunch of sources here; see that article for citations and a more scholarly treatment.

Abadan, Iran, Company Town:  Top-Down Neighborhood Formation
Deir el-Medina, ancient workers village

The company town is a settlement planned and established by a central organization to house its workers so that they can work more efficiently. They tend to exhibit careful planning and regularity of housing; they show some evidence of the central authority; and they are physically set off from their neighboring settlements. We tend to think of company towns as modern features, used by capitalist enterprises. But the basic concept goes back to ancient Egypt at least. Pharaohs set up walled settlements that archaeologists call "workers villages" to house construction workers, or temple personnel. This was not by any means a capitalist economy, yet the form, function, and goals of workers villages matched closely those of a 19th century town like Pullman, Illinois. These settlements are one of the main types of what Kevin Lynch called "the city as a practical machine."

My example here is Abadan, an oil refining town set up in the early 20th century in Iran by the Anglo-Persion Oil Company (later known as British Petroleum). The company knew they would need to bring in workers from several national/cultural groups, and they were worried about possible trouble that could come if members of these groups could easily mingle with one another. So thay arranged the housing in a big band around the outside of the refinery, and
they kept individual neighborhood units separate from one another. The British executives and engineers were in one area, and various local and Near Eastern groups were distributed in other areas.
Neighborhoods laid out around the refinery, which was in the center

British neighborhood in Abadan
The plan to settle groups in physically separate neighborhoods was quite deliberate, as research into company archives has shown (see Smith et al 2015 for citations). So, Abadan ended up with a system of neighborhoods, distinguished culturally and socially, as a result of deliberate planning from the
top. Such "designed neighborhoods" are also found in other company towns, and in other regimented planned settlements such as internment camps.

Occupy Portland Protest Camp: Bottom-up Neighborhood Formation

Information from the Occupy Portland camp was gathered by Katrina Johnston-Zimmerman for her MA thesis. Katrina is an interesting urbanist; check out her "Think Urban" website or her Twitter feed. As an undergraduate at Arizona State University, Katrina worked for our interdisciplinary urban project, "Urban Organization through the Ages." She conducted ethnographic fieldwork during the "Occupy Portland" event of 2011. This was one of the many local protest camps that spring up following the initial Occupy Wall Street settlement.
Occupy Portland camp. Photo by Katrina Johnston-Zimmerman

What Katrina found was that the campers in Portland quickly formed spatial clusters of like-minded people who spent time together. They set up their tents near one another. These groups took on names. In short, these were neighborhoods. This is a clear example of the bottom-up route to neighborhood formation. People created neighborhoods on their own, following their needs and interests. No one came along and organized the campsite. In fact, the participants in the Occupy Portland event refused to submit to a top-down organization. Someone pointed out that the campsite looked messy. If they reorganized it to look neater, with tents in nice rows, then the authorities would be less likely to tear it down. (This is a basic principle in informal settlement invasions in Latin America; local governments are far less likely to destroy shantytown settlements when they have neat streets and lots than when they are a mess).  But, true to their anarchist orientation, the participants refused to submit to this top-down structure. The messy, grass-roots organized spatial organization of neighborhoods was too strong to be torn apart in an effort to please city officials.

The Burning Man Festival: From Anarchy to Planning

The annual Burning Man festival in the Nevada desert is a fascinating case study of a semi-urban settlement. What began as a bonfire on the beach in San Francisco in th 1980s has grown into a huge annual campsite with as many as 70,000 week-long residents. It has always been a festival of arts and free expression, run with a series of anarchist principles, including radical inclusion, decommodification, communal effort, radical self-reliance, and leave no trace. The entire settlement is taken down each year, all traces are removed or destroyed, and then it is planned, surveyed, and built again the following year. Urbanists have only just begun to study Burning Man, and there is much to learn there about cities, urbanization, and social patterns.

The Burning Man site is on federal land, and the festival receives a permit each year. As the festival grew during the 1990s, people naturally gravitated toward specific areas, forming neighborhoods. These were linked by friendship and social bonds, as well as by interests (e.g., all-night loud parties in one area; campers with small children in another). But by 1996, the event had grown too large to function on its anarchist principles. People were shooting guns in crowded places, driving cars too fast and destroying tents and injuring people. The government threatened to shut down the festival (by denying the permit) unless more order were achieved.

Almost overnight, the site -- called Black Rock City -- became a heavily planned settlement, with a circular layout and the burning man tower in the center. There is now a "Department of Urban Planning" in the Burning Man organization. Neighborhoods were either continued, or established anew, again, using social bonds and common interests as defining features. These anarchists were able to submit to some top-down planning in order to continue to celebrate their anti-authoritarian and free-expression values.

Whereever you look, there are neighborhoods!

These are just three examples of semi-urban settlements with clear neighborhood organization. Our study found neighborhoods at many other types, from Plains Indians tipi camps to refugee camps. The conclusion I draw from this study is that neighborhoods are indeed a  universal feature of urban life. Whether created and enforced by authorities (state or corporation), or generated by grass-roots action of individual acting in their own, neighborhoods are an integral and crucial part of urban organization, from the distant past to the present.

For more details, see:

Smith, Michael E., Ashley Engquist, Cinthia Carvajal, Katrina Johnston, Amanda Young, Monica Algara, Yui Kuznetsov and Bridgette Gilliland  (2015)  Neighborhood Formation in Semi-Urban Settlements. Journal of Urbanism 8(2):173-198.

Sunday, June 26, 2016

Why we need to disentangle the concepts of city and state in the ancient world

Many people will be puzzled by this title. The city and the state are separate concepts that refer to very different things. Why would they need to be "disentangled"? But in my own home discipline—anthropological archaeology—these two concepts have long been wrapped up together in a single package. A long-standing goal of anthropological archaeology has been to figure out the origins of early cities and states. But when cities and states are not distinguished, that goal has been impossible to reach. Now evidence is accumulating that archaeologists can't ignore, and it is time to give up the old view once and for all.

Fig. 1: Old archaeological view of state and city origins

Figure 1 shows the standard model for state origins in anthropological archaeology. Various factors led to the establishment of the earliest states (archaeologists have argued a lot about the relative importance of those factors). Once states came into being, cites came along too, for the ride. Archaeologists didn't think that urbanization required a separate theory. About fifteen years ago I started focusing my comparative attention on cities and urbanization. I quickly realized that while these old views were inadequate, they were deeply engrained. I recall not long ago emailing an Egyptologist with a question about early cities in Egypt (I forget now just what I asked). This person's response was, "I can't help you, because I haven't worked on state origins for many years." Say, what? I hadn't asked anything about states, I had asked about cities.

I think one reason archaeologists were slow to separate states and cities, was because most cities in the ancient world were dominated by politics, and not by economics. Today, cities are all about economics: factories, production, trade, commerce, firms, and employment. Political processes play a decidedly secondary role for most urban issues. But in the deep past, on the other hand, most cities were all about politics. They were capitals where kings lived, or state outposts where bureaucrats operated. Economic activity took a back seat to political activity in generating urban growth and shaping the nature of cities (Jose Lobo and I develop this theme in a paper now under review, "Cities through the Ages: One Thing or Many?"). Since cities were essentially political institutions, it seemed natural to link urbanization to state formation.
Figure 2. State traits and urban traits, from Chick (1997:294)
Nevertheless, cities and states are quite different, whether we are talking about nation-states today or the early states and empires. Figure 2 shows one small piece of evidence supporting this idea. This table, from an article by Garry Chick (1997), shows the results of a factor analysis of a cross-cultural sample of human societies. The Standard Cross-Cultural Sample is a collection of human societies described by anthropologists that can be analyzed statistically (see Ember and Ember 2009). In this study, Garry Chick examined how a number of social variables were associated in the sample. He identified two factors, or principal components. Factor 1 has high loadings for variables related to administration and economics (red box). This shows that these traits are strongly correlated; they come as a package in some societies. Societies either tend to have writing, money, and social stratification, or else they tend to lack these things. These are state-related variables. A second set of variables scored high on Factor 2: these are urban-related features (residence patterns, density, urbanization, and agriculture). The interesting thing is that principal components defines factors that are independent of one another ("orthogonal" is the technical term). That is, knowing the score of a society on Factor 1 will not help you predict its score on Factor 2. In other words, urban features are basically independent of state features when a wide range of human societies is considered.

A recent book by Justin Jennings, called Killing Civilization: A Reassessment of Early Urbanism and its Consequences provides more evidence for the need to separate cities and states in the distant past. This is a fantastic book, and I will blog about it in more depth before long. For now, I want to emphasize one particular strand of Jennings's argument. He proposes two reasons why archaeologists and anthropologists should abandon the concept "civilization." First, the concept "helped justify colonial and racist projects of the 19th and early 20th centuries" (p. 266). If some societies are "civilizations" and others are not, this implies some peoples are civilized and others are not. But this is more of an evaluation, a value judgment that has often justified racism, and less of an analytical term. Therefore scholars should give up the concept of civilization. I agree.

Second, the idea of civilization—as in "the rise of civilization"—confuses state formation and urbanization by implying that they are both parts of a single package that came into being all at once. Much of Jennings's book is devoted to examples of early urban settlements that developed prior to state organization. If urbanization preceded state formation, then these two processes must be disentangled if we are to make any sense at all of early developments. I REALLY agree!

This last point gets into the broader and very important issue of how urbanization generates changes in society, and how the results of living together in dense settlements may have led to early state formation. This is a theme I have been working on recently; see some of my prior blog posts (such as Cities as social reactors, or Settlement scaling and social science theory). I have some papers in press and under review on this topic. But this kind of new approach only makes sense when archaeologists have actually disentangled processes of urbanization and state formation. From the point of view of comparative social-science research on cities, this is a no-brainer. But some archaeologists still need to wake up to urban reality, and Justin Jennings's book is a big step in the right direction.

Chick, Garry
1997  Cultural Complexity: The Concept and its Measurement. Cross-Cultural Research 31: 275-307.

Ember, Carol R. and Melvin Ember
2009  Cross-Cultural Research Methods. 2nd ed. AltaMira, Walnut Creek, CA.

Jennings, Justin
2016  Killing Civilization: A Reassessment of Early Urbanism and its Consequences. University of New Mexico Press, Albuquerque.

Wednesday, March 23, 2016

Settlement Scaling and Social Science Theory

In this post I explore several branches of social science theory that support the social reactor model of settlement scaling. This is a continuation of my prior post, which explored the basis for comparing urban and village settlement systems. Like that post, this one is exploratory in nature, and I would really welcome feedback on these ideas. This post is a bit more academic and detailed than most in this blog, for which I apologize. Here is an outline of the scheme.

1. Theories of population growth and its effects
  1. Large-scale social consequences of population size
  2. Scalar stress
  3. Dual inheritance theory
2. Community theory
  1. Social interaction generates communities
  2. Social interaction generates successful communities
  3. Communities can accomplish goals
3. Urban economics

Yes, I realize this is a motley collection of themes—some are well-worked out theories or theoretical approaches, one is a discipline, and others are specific research topics or claims. But as Ralph Waldo Emerson said, “A foolish consistency is the hobgoblin of little minds.” I am not any kind of theoretician, and I’m afraid this is the best I can do for now. Don’t like this scheme? Then help me out; send me comments and critiques.

1. Theories of population growth and its effects

The first group of theories focus on the role of population growth—and population size—on society and behavior. This is a long-standing research theme in the social sciences. I divide this area into three categories.

A. Large-scale social consequences of population size

Social scientists have recognized the large-scale social consequence of increasing group size for more than a century. The great sociologist Georg Simmel noted in 1898: “Every quantitative extension of a group requires certain qualitative modifications and adjustments” (Simmel 1898:834).” The growth of larger social groups, and the association between group size and socio-political complexity, have been major themes in the literature on cultural evolution in anthropology. Quantitative analysis directed at this theme was common in anthropology in the 1950s and 1960s (Carneiro 1962; Naroll 1956), and this work even included some early settlement scaling analyses (Cook and Heizer 1965)!

A popular topic of research on population change in the 1960s and 1970s was the role of “population pressure” in generating various social changes (Cohen 1977; Spooner 1972). The resulting consensus held that simplistic models positing population increase as the sole cause of political change were inadequate; for example, Carneiro’s (1970) model of population growth causing warfare, which in turn caused the rise of states, is rarely invoked now, except as a foil or a historical note. But narrower models, focused on economic and environmental variables—such as Netting’s (1993) model of population pressure causing agricultural intensification in smallholder farming—have fared better with time, even appearing in best-selling popular science books (e.g., M.E. Smith 2016a) (well, I hope I do sell a few copies......).

The two relationships mentioned above—(1) group size has increased over time in many areas of the world; and (2) group size is strongly predictive of sociopolitical complexity—might be considered “stylized facts” in archaeology. That is, they are well-documented relationships whose explanation has been the subject of dispute. I am intrigued by the concept of stylized facts in economics, and I’ll probably blog about this on Publishing Archaeology soon. But the relevant conclusion here is that group size is important, and—in some circumstances—has causal effects on social and economic life. This is similar to the claims of the social reactor model, although the cultural evolutionary models tend to gloss over specific social interactions within set places in their pursuit of more general results. If this discussion does not seem sufficiently “theoretical,” then I’ll invoke the “demographic-structural theory” of Jack Goldstone (1991, 2002), further elaborated by Turchin and Nefedov (2009). This is a productive political-economy approach in economic history and historical sociology that melds population increase theory with structural models of power relations.

B. Scalar stress

Archaeologist Gregory Johnson (1982) coined the term “scalar stress” to refer to social stress or difficulties created by increases in the size of a social group. His focus was on the size of the decision-making group, and he analyzed the development of hierarchies of social decision making as group size increases. Research on scalar stress focuses on the negative aspects of larger social groups. The best-known archaeological example is Roland Fletcher’s (1995) model of thresholds in settlement size and density, caused by scalar stress. This kind of analysis of archaeological site size continues today (Alberti 2014).

There is a large literature in social psychology on the role of population density in generating psychological stress (Evans 2001; Spruill 2010), and research on the “urban health penalty”—the negative health consequences of living in dense cities (Vlahov and Galea 2002; Vlahov et al. 2004)—follows a similar tack. In fact, if we step back a bit, there is a major historical line of research in sociology on the negative effects of growing city size. This is too big a topic to get involved in here (and I don’t know if very well......), but one element that remains a topic of discussion after many decades is “social disorganization theory,” concerning the negative social consequences of urban life, particularly in large cities (Kornhauser 1978; Kubrin and Weitzer 2003; Sampson 2004).

Scalar stress and social disorganization theory are relevant to settlement scaling in that they emphasize the negative consequences of life in large cities. Urban scaling of contemporary cities shows that superlinear scaling is not only about positive economic outputs; crime, poverty, and disease rates also exhibit superlinear scaling (thanks to Deborah Strumsky for her nice lecture today at ASU, reminding us about superlinear scaling of disease levels). Social interactions in the built environment have both positive and negative consequences.

C. Dual inheritance theory

Dual inheritance theory is about how human genes and culture evolve separately, yet inter-relatedly; they co-evolve. Starting with Boyd and Richerson (1985), this is now a major line of research in anthropology and biology (Henrich 2015; Richerson and Christiansen 2013). What does it have to do with scaling? A major focus in dual inheritance theory is the mechanisms of cultural transmission. How do people learn from others? How do new traits arise and spread through a population? What are the roles of skill, teaching, prestige, and conformity in the spread of knowledge? Many of these traits depend on population size.

This research is relevant to settlement scaling in its analysis of how the size of social groups relates to technology and other cultural adaptations. No single person in any social group has all of the knowledge needed to survive or to reproduce the group’s culture. Successful cultures require the combined knowledge and skills of many members. Larger groups have a greater diversity of tools and concepts (Henrich 2015), and if a group gets too small, it can lose effective technological adaptations rapidly, as in ancient Tasmania (Henrich 2004).

Unfortunately, the dual inheritance scholars have not thought much about how their models relate to settlements and urbanism; their models lack a spatial dimension. If technological diversity depends on group size, then perhaps larger settlements have distinctive technological attributes compared to smaller settlements. But the emphasis on learning and cultural transmission of dual inheritance research does relate to the social interaction basis of the social reactor model.

2. Community theory

By “community theory” I mean work from a political-economy perspective that studies communities as sites of social interaction. This perspective diverges from a common approach to communities in archaeology, in which the emphasis is on idealist and social constructionist models that claim communities are generated by shared meanings in people’s heads. For some discussion of these differences, see two posts on Publishing Archaeology:  here,  and here. I sometimes wish I worked in a discipline that didn’t have so much silliness and ridiculousness taken seriously as theory.

The three sections that follow are not distinct theoretical approaches; they are major claims of the political-economy approach to communities. This approach—particularly these three claims—is broadly supportive of the social reactor model of settlements.

A. Social interaction generates communities (“connection, not affection”)

The dominant view in the social sciences views communities as generated from processes of social interaction. This goes back to Emile Durkheim at least. Sociologist Steven Brint (2001) shows different definitions of community in a nice tree diagram:

Notice that neighborhood groups and other social communities (lower left) are based on activities and frequent interactions. Here is how economists Sam Bowles and Herbert Gintis (Bowles and Gintis: F420) define community:

“By community we mean a group of people who interact directly, frequently and in multi-faceted ways. People who work together are usually communities in this sense, as are some neighbourhoods, groups of friends, professional and business networks, gangs, and sports leagues. The list suggests that connection, not affection, is the defining characteristic of a community. Whether one is born into a community or one entered by choice, there are normally significant costs to moving from one to another.”  (p.F420)

Most definitions of community in the social sciences are based on three factors: social interaction, spatial locality, and some kind of common ties (Hillery 1955; Jabareen and Carmon 2010). My definition of neighborhood—intended to be useful for archaeologists—is quite similar (M.E. Smith 2010). Again, see my prior blog posts for a critique of the social constructionist views of community in archaeology (here, and here), or see my paper on quality of life (M.E. Smith 2016b).

B. Social interaction generates successful communities

Social interaction is emphasized in a number of normative theories of successful communities. Anthropologists and archaeologists, take note: planning and other social scientists use the term “normative” in a very different way than it is used in anthropology and archaeology. Normative in these other fields means theory with an evaluative dimension; for example, theory about what makes for “good city design” (Lynch 1981) is called normative theory. I discuss this briefly in Smith (2011).

How to use urban design to promote social interactions is a major component of normative planning theory. Social interactions—with friends, neighbors, and other residents—are seen as one of the prime indicators of successful cities and towns. Social interaction—particularly in reference to neighborhood physical facilities like parks, playgrounds, and pedestrian-friendly streets—is a key dimension of social cohesion in cities (R.A. Smith 1975). Urban planners give considerable attention to designing neighborhoods and streets that promote interactions (Kısar Koramaz 2014). Stable neighborhoods facilitate social interaction, which promotes social cohesion or integration (Brower 2011).

Here are some passages from Robert Putnam and Lewis Feldstein, in their book on social capital and successful communities in the U.S. today:

“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 ... Urban planning, architecture, and technology can each fosters redundancy and multistrandedness by creating opportunities for encounters that knit together existing ties. Because local arrays of built space and communications technology act as ‘background structural factors’ in most of our cases, their true importance is not always manifest.” (Putnam and Feldstein 2003:291)

C. Communities can accomplish goals

Communities are important not just as places where people live, but also because they can accomplish tasks and get things done. The great social scientist Charles Tilly (one of my intellectual heroes) asked, “Do communities act?” (Tilly 1973). He was discussing the ways in which communities in early modern France applied resources toward common goals. This line of analysis has continued in several branches of the social sciences. Bowles and Gintis, for example, note that communities can solve problems that are difficult for markets or states to solve. See their typology, based on the differing types of social relations that characterize the three kinds of institution:

Bowles and Gintis (2002:F422-F423) state:

“communities solve problems that might otherwise appear as classic market failures or state failures: namely, insufficient provision of local public goods such as neighborhood amenities, the absence of insurance and other risk-sharing opportunities even when these would be mutually beneficial, exclusion of the poor from credit markets, and excessive and ineffective monitoring of work effort. Communities can sometimes do what governments and markets fail to do because their members, but not outsiders, have crucial information about other members’ behaviours, capacities, and needs. Members use this information to uphold norms.”

The ability of communities to act—effectively and with positive outcomes—is at the heart of the work of Elinor Ostrom (1990, 2005). One of her basic arguments parallels precisely the argument of Bowles and Gintis: local communities can manage common-pool resources more successfully and sustainably than either states (government ownership) or markets (privatization). Here is her basic model:

Notice the role of face-to-face communication on the left side. Basic social interactions within a community promotes trust, reputation and reciprocity.

The upshot of this perspective on communities is that social interactions in a specific spatial locale have a variety of positive effects for residents. These effects are felt on both the individual and the group levels. To these basic findings of social science research, the social reactor model of settlement scaling adds two things: (1) social interactions in a given built environment have an even wider range of specific outcomes than social-science research might suggest; and (2) they exhibit a surprising level quantitative regularity.

3. Urban economics

I’ve just about run out of steam here. I guess that’s a convenient excuse to avoiding talking about a discipline I know little about. So let me just cite an article that not only has a fantastic title—“Buzz”—but also provides an excellent introduction to the role of face-to-face interaction in cities (Storper and Venables 2004). And I will close with two brief quotes from urban economist Edward Glaeser’s excellent book, The Triumph of Cities (Glaeser 2011):

“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.” (p.250)

“Cities enable the collaboration that makes humanity shine most brightly. Because humans learn so much from other humans, we learn more when there are more people around us.”  (p. 247)


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