Universal patterns in the emergence of complex societies

Team lead: Jerry Sabloff, President, Santa Fe Institute

In this project we seek to understand the reasons for the rise of complex forms of social, political, and economic organization that have been of profound interest to archaeologists, social scientists, and historians. We shall proceed by transforming the current global database on early urban states and combine it with methodological and conceptual tools from complexity science. We will then develop new explanations for the strong cross-cultural regularities in the emergence of early urban state societies. Urban-centered states have emerged independently in a variety of settings, beginning in southern Mesopotamia more than 5,000 years ago. Archaeologically, they can be identified by such markers as a multi-tiered settlement hierarchy, administrative buildings, and economic specialization.

Why, after many millennia of successful adaptations to village farming life ways, did complex urban states emerge in at least six unrelated places across the globe? Why have urban states been such successful adaptations to social life? What factors have drawn people to cities despite their many drawbacks, and can we illuminate the heretofore hidden factors behind the success of this particular social innovation? To what extent was the emergence of urban states driven by the scaling laws that characterize contemporary cities, and to what extent do the conditions surrounding the emergence of urban states reflect those associated with the evolution of complexity in other living systems?

Empirical data about these key evolutionary transitions have grown quite strongly over the past few years (Sabloff, in press) through a host of archaeological research projects. In this respect archaeology is undergoing a change comparable to the data deluge in biology. This research has produced new insights on some of the principal factors involved in the emergence of complex societies; despite much attention and interest, however, the construction and testing of theoretically-driven explanations for the development of cultural complexity in general, and the rise of the urban state in particular, have lagged behind.

This lag is due to a number of factors. Until recently, one factor has been the paucity of good comparative studies (for an early exception, see Adams 1966; also see Renfrew 1972) due in part to the necessary emphasis on site-specific empirical research and on the collection of regional settlement data. However, in recent years some useful comparative studies have appeared (Feinman and Marcus 1998; Marcus and Sabloff 2005; Trigger 2003, among others) and these have identified a number of important variables involved in the emergence of complex urban states (also see Spencer and Redmond 2004). We will build upon these insights.

Another reason theory-building has lagged behind is that, although efforts to build comparative databases for the study of human cultural history are underway, at present these compilations either emphasize nominal-scale coding (e.g. Peregrine 2003) or cover only small portions of the spectrum of global and historical social complexity (e.g. Wright 2006). Yet, in order to uncover the deep principles governing the evolution of human social complexity, it is necessary to transform these compilations into a truly global dataset that captures salient characteristics of the full range of human societies.

We are particularly encouraged in this regard because many archaeologists working on the emergence of social complexity today have adopted a complex systems perspective -- pioneered at the SFI -- that involves fully interdisciplinary approaches to the study of individual complex societies, including landscape studies, ecological studies, and a host of chemical and biological studies. In addition, many are using quantitative modeling to simulate and clarify the relevant evolutionary processes (see, for example, Gavrilets et al. 2010; Kohler et al. 2011; Spencer 1998; Wilkinson et al. 2007). Given the recent accumulation of accessible data on early urban states (and many other ancient societies) and the re-emergence of comparative studies, we are now in a position to make significant theoretical advances concerning this key episode of emergence that provided the foundations of the contemporary world.

A major goal of this project is to identify quantitative relationships among key variables across all levels of complexity in human societies. Most studies of primary state formation focus on settings where such societies actually emerged, as opposed to settings where they might have but did not (for an exception, see Varien et al. 2007). Yet the most compelling theory regarding complexity in human societies needs to place complex urban states within the framework of all human societies (see Renfrew and Bahn 2011 for a recent overview); thus, a key thrust of this project will be to expand existing compilations of world-wide archaeological data, translating archaeological sequences into quantitative measures so that we can discover the fundamental relationships among key variables spanning the entire history of humanity.

Throughout this project we seek to determine whether the emergence of complex societies reflects the realization of economies of scale inherent in complex systems, or reflects instances where humans have created these economies through various forms of innovation. Does the emergence of social complexity involve the realization of a latent potential, as suggested by scaling laws in contemporary cities, or the creation of new potential, as suggested by studies of evolutionary innovation? This is a difficult question to answer for any complex system, but recent perspectives from other historical sciences (Arthur 2009; Erwin 2008; West. et al. 1997) suggest that both may have contributed. For example, in biology, the evolution of photosynthesis created conditions in which terrestrial animal life could evolve and larger organisms also operate more efficiently on a metabolic level. To what extent have evolutionary innovations and scaling laws contributed to the emergence of early urban states (also see Shennan 2009, among others, for a general evolutionary perspective in archaeology)?

As noted above, some comparative archaeological data suitable for the goals of this project are already available. For example, Peregrine and Ember’s (2001-2002) Encyclopedia of Prehistory provides descriptive information and references for 289 archaeological traditions, sampled through time and space and arranged into chronological sequences. Peregrine’s (2003) Atlas of Cultural Evolution scores these 289 archaeological traditions (see Fig. 4) on features such as degree of urbanization, social stratification, political integration, and technological specialization, based on Murdock and Provost’s (1973) scales of “cultural complexity”; additional descriptive information is available through the eHRAF Archaeology database (http://www.yale.edu/hraf/archaeology.htm). Finally, Wright (2006) provides quantitative measures and references for 18 early states and chiefdoms. The empirical component of this project emphasizes compilation of additional data and variables that complement and extend these existing databases. In particular, we seek to transform the 3-point scales of Peregrine’s (2003) Atlas of Cultural Evolution into quantitative measures and incorporate a temporal dimension by compiling these measures for the periods of peak development for each non-state system, and for the period immediately before, during and after primary state formation in each urban state system. While the resulting dataset will likely contain some fraction of missing values, we are confident that the range of expertise represented in the research team will allow us to substantially augment the global comparative archaeological database in both quality and quantity.

Comparative studies have identified five factors that are characteristic of early urban state emergence. Below we briefly discuss each of these and identify quantitative measures derived from the archaeological record that can serve as proxies for these variables, and that we aim to compile as part of the empirical component of this project.

Population/resource balances: Archaeological research indicates that the rise of early urban states is universally associated with population growth, but that population growth does not always lead to the rise of social complexity. Mann (1986), Spencer (1998) and Carneiro (1970) suggest that a process labeled ‘circumscription’ or ‘encagement’ is a prerequisite for the rise of complex urban states; in such situations individuals do not have the option of moving elsewhere to obtain critical resources. To investigate the role of these variables it is necessary to collect data on the absolute population size of a settlement system, the total area of agricultural production within it, and the basic productivity of food staples grown or collected to provide the bulk of subsistence. There also have been significant advances in measurement in this area, which we intend to build on (see, for example, Kowalewski 2003 or Hill et al 2004b).

Territory formation: In several cases, urban state emergence involved the unification and pacification of smaller, previously antagonistic polities and the abandonment of multiple competing centers in favor of a single capital city (Marcus and Flannery 1996). This was likely achieved through military conquest and maintained by policing and appears to be the case in non-urban states, as well (Kirch 2010). To investigate the role of these variables it is necessary to devise measures of political competition and warfare. These can be obtained through quantitative summaries of settlement size distributions, the total areas of political systems as defined by settlement and material culture distributions, and frequencies of premortem and perimortem trauma on skeletal remains.

Specialized production and exchange: Urban state formation is often associated with a dramatic expansion in economic specialization and a formalization of exchange networks. In some cases specialized production took place under direct control of political authorities, whereas in others it was independent (Brumfiel and Earle 1987). The extent to which these economic processes encouraged or resulted from urban state formation can be examined by quantifying workshop and market space within settlements; estimating proportions of material goods that derive from specific workshops; characterizing the modes of transport for, and distances over which goods were imported to early cities, and measuring the agricultural hinterlands surrounding such cities. Technological innovation rates can also be estimated from the appearance of new artifact types in assemblages.

Investment in public works: Previous studies suggest investments in public works -- temples, administrative buildings, marketplaces, aqueducts, roads, and so forth -- were emphasized during periods of initial state emergence (Mendelssohn 1974, for example). To investigate the role of such investments, it will be necessary to quantify their energetic costs for material acquisition and construction (see Abrams 1994 and Abrams and Bolland 1999, among others).

Sanctification of authority: Most cases of early state formation are associated with iconographic and architectural evidence suggesting new forms of persuasion that cemented the political authority of rulers (e.g. Marcus and Flannery 1996). This basic pattern suggests that, in addition to political, military and economic innovations, primary state formation involved innovations in ideology as well. The ideological dimension of urban state emergence can be examined through the identification of specific analogies related to political authority in the material culture, oral traditions, and written records of early state societies (Ortman 2000). For example, early Hawaiian kings were presented as “sharks who devour the land” (Kirch 2010), whereas Mayan kings were presented as maize gods who brought abundance to their people (Schele and Miller 1986). Although these data are only likely to be quantifiable on a presence/absence basis, such data, collected across a range of ancient societies, should be sufficient to identify patterns in the favored analogies of early state ideologies vs. societies that did not make the transition to statehood.

In addition to testing specific hypotheses developed in previous research, the data collected as part of the project will be used to address several issues that arise when one considers the rise of urban state societies from a general complex systems perspective. One such issue is the interplay between micro- and macro-evolutionary processes in the evolution of social complexity. For example, a key question is how the behavior of individuals and households at the micro-evolutionary level affects long-term patterns that emerge at the macro-evolutionary, societal level (e.g. Kohler et al. 2007; Field et al. 2011). Did different forms of social organization in earlier and smaller-scale societies, such as different forms of family structure (e.g. Fortunato 2011), significantly influence their trajectories on the path to increasing scale and complexity?

In summary, this project will have three components: 1) creation of a new and enriched global comparative archaeological database containing measures of social complexity for early urban and other ancient societies; 2) exploring the scaling relationships among factors associated with the emergence of social complexity in comparative studies using this dataset; and 3) using phylogenetic analysis, agent-based simulation, network analysis, and cross-cultural methods for explaining a key episode of emergent complexity in human history.

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