Models in archaeology

Submitted by Sammy Smith (sammy@thesga.org)

Google_Earth_globe_centered_Georgia.jpg

Google Earth model of the earth, centered on the modern state of Georgia.

Archaeologists use models in their work. These models are simplifications of reality—not well-dressed people! Models are tools used to better understand the real world. They help us visualize what has happened and predict data we don’t yet have and patterns we have yet to see. Thus, models give us, in essence, a template for reality.

Models begin with data. Data in archaeology are quite variable. You are probably most familiar with material remains like artifacts, and maybe features. But archaeologists also draw data from other sciences, like soil chemistry, climate reconstructions (which are data-based models), and plant genetics, to name a few.

A physical model may be a small version of something much larger and more complicated. A six-inch long model car may have the same general shape and some details of a real car. But, for example, the doors may not open. Similarly, it may not have an engine—or if it has a small engine, it will not be a tiny version of the engine in the full-sized car. The model car is a representation of a larger reality, fairly accurate in some details, and entirely skipping some aspects of the “real thing.”

Scientific models simplify reality, yet accommodate known data. Maps are models. Think of representations of the New World, of the two continents of North and South America with Central America in between, and islands to the east in the Caribbean. Various techniques are used to translate the three-dimensional form of the Earth to a two-dimensional representation on a piece of paper or computer screen. The computer-screen allows three-dimensional representations, however. Still, some details must be approximated and accuracy sacrificed to create the map. But, the map remains useful, despite the error it contains.

Archaeological models, like the data they are built on, are quite variable. They may be broad, as of social change or economic exchange. They may be regional, as of Mississippian trade and exchange patterns in southeastern North America.

Social models, like maps of the Earth, approximate reality. Good models match available data. As new data are obtained, models are adjusted or dismissed to accommodate the new data.

Models must simplify complexity, yet approximate the structure the data indicate exist in the real world. In ecology, the structure would be the relationships we see among species. For example, the bees need flowers to gather the pollen they need for food. The plants that have the flowers need air, light, water, and nutrients to grow. They also may need the bees to pollenate them, so that the plants can reproduce and persist year after year. This is a small example of a systemic, structural relationship in the ecological realm.

Social scientists also model human relationships and other behavioral situations. One well-known model is of cultural evolution sometimes called the band-tribe-chiefdom-state model. About a half-century ago, Elman Service proposed that these were stages in social evolution, that in the most ancient times, humans organized themselves in “simple” societies he called bands. As the social group incorporated more people, he argued, societies evolved to a stage he called tribes, and then to chiefdoms with even more people, and finally to states. Subsistence activities changed along with the changes in sociopolitical organization.

Bands are seen as hunter-gatherers, who foraged for food in the wilds, and probably moved their camps at least seasonally through the year. In Service’s model, bands may have had elders, but leadership was mostly informal and situational. Otherwise, bands had no entrenched leadership hierarchy or social status.

Tribes incorporate more people, and also have some form of social hierarchy, or social rank. Archaeologically, social rank is evident in remains that include fancy crafted goods, such as carved shells, or items that had to have come from far away (for example, tools made from types of stone not locally available).

Chiefdoms, in Service’s model of social evolution, were defined as having a more developed social hierarchy, with some centralization of authority, such that the highest-ranking leader may not reside in a given community. In a functioning chiefdom, people have to solve tensions that may arise from issues of the legitimacy of leaders (how did they achieve their leadership role, and how do they maintain it?). Chiefdoms may have several levels of leadership, with a paramount leader who has a higher rank than subchiefs.

States, then, had more people, and institutionalized leadership and other organizations that provided a framework for life and sociopolitical interactions. States may take myriad forms, but have more hierarchy and more complexity than chiefdoms.

Thus, each stage of Service’s model of social evolution is itself a model—of social organization—and the evolution from one stage to another is another model.

Succeeding researchers have disagreed with Service’s band-tribe-chiefdom-state model from several angles. They have disagreed with his stages, and they have disagreed that stages are even a good way to conceptualize social evolution. In short, the idea of stages has been challenged. And, the general trend toward increasing complexity also has been challenged. The most fundamental criticism lies in the lack of dynamism in the stage model; it fails to conceptualize the transition between stages. After all, evolution indicates change, so a model of evolution that does not explain or indicate how the change happens is by definition deficient.

Models, however, are approximations of reality. Even deficient models are heuristic aids—they help us to understand a reality that is too complex to conceptualize without a model. So, even if we dismiss a model, it has helped us understand the more complex reality.

Perhaps you can think of an example of a model archaeologists use in understanding our human past. Log in and tell us about it.