IX.

Interpreting the Archaeological Record

Once a site has been documented, mapped, and dated, the archaeologist tries to integrate all the data into a coherent and understandable picture of the past. Archaeologists draw from what is already known of the archaeological record to develop their interpretations. Their new interpretations then add to that body of knowledge.

A.

Classifying Archaeological Finds

Everyone classifies objects—we know the difference, for example, between eating utensils and automobiles. We also make choices among objects—we choose a spoon to eat soup and a fork for salad, and we use large trucks to carry loads but small cars to save gas. The objects that archaeologists study were all once classified in similar ways by the people who originally made or interacted with those objects. Thus, archaeologists classify their finds to help them understand past cultures.

In archaeology, classification is a research tool that is used to distinguish among different artifacts and other material objects. Archaeologists use various systems of classifying artifacts to organize data into understandable units. Archaeological classifications describe artifact types, such as different forms of pottery, as well as relationships among different objects of a common type, such as clay vessels. Archaeologists call this system typology—a hierarchical classification based on artifact types and groupings.

When studying thousands of stone tools or potsherds, archaeologists search for patterns in them, such as of shape, color, and material composition. These patterns become the variables that define each category of object. For example, the category “containers” may include such objects as shallow bowls and round-based pitchers with curved handles.

After grouping the artifacts from an excavation into specific types, archaeologists determine the sequence in which those artifact types existed in the past. The process of determining this sequence is called seriation. Archaeologists believe that sequences of artifact types, or seriations, illustrate how past cultures changed over long periods of time.

Archaeologists often analyze artifact type sequences from many sites covering large areas of land. The comparison of multiple type sequences can show how particular types of artifacts spread from one group of people to another in the past. For example, during a period of over 1000 years beginning in about 1500 bc, a distinctive shell-ornamented pottery known to archaeologists as Lapita ceramics spread widely from one island to another in the southwestern Pacific. The continual evolution of Lapita pottery and other items across islands shows that the people maintained an extensive canoe trade in volcanic glass and other materials.

B.

Tracing Cultural Exchange

From the earliest times, human societies have exchanged raw materials and manufactured items with their neighbors and even with people living in other areas. People have traveled particularly far for valued materials—such as the best toolmaking stones, metal ores, and seashells—or for artifacts not manufactured locally, perhaps mirrors or wrought metal tools. When archaeologists find known artifact types far from their place of origin, they can begin to piece together ancient patterns of trade. For example, Celtic tribes in central and western Europe imported wine in Greek vessels from Mediterranean lands sometime around 200 bc. Several archaeological studies have traced the extent of this trade by plotting the distribution of such vases along the Rhine and Rhone river valleys.

Increasingly, archaeologists are turning to techniques that allow them to trace the source of materials in ancient trade. For example, analyses by George Bass and Cemal Pulak of the copper ingots they recovered from the Uluburun shipwreck off southern Turkey showed that the copper came from mines in Cyprus. Numerous analyses of this type have revealed that trade assumed increasing importance over time during the ancient past, especially with the rise of early civilizations in Egypt and Mesopotamia after 3000 bc.

C.

Explaining Cultural Change

Until the 1950s, archaeologists were concerned mainly with the study of artifacts and cultural sequences. However, the increased use of radiocarbon dating and of computers and other high-technology scientific methods in archaeology led to a major theoretical revolution in the 1960s. This new approach to archaeology placed a major emphasis on environmental reconstruction, the study of ancient ways of life, and the use of advanced analytical tools. Above all, researchers practicing this new form of archaeology stressed the importance of explaining how past cultures developed and changed. Because they were primarily interested in cultural process, these archaeologists came to be known as processual (process-oriented) archaeologists and their work as processual archaeology.

Processual archaeologists think of human cultures as systems that interact with their surrounding ecosystems—interdependent systems of plants, animals, landscapes, and the atmosphere (see Ecology: Ecosystems). Processual archaeologists collect large amounts of environmental data in order to understand these relationships. To processual archaeologists, major cultural developments, such as the origins of agriculture and civilization, are highly complicated sequences of events that involve a series of interacting and constantly changing factors. Many earlier archaeologists, by contrast, believed that such developments were the result of single causes, such as a change in weather patterns or an increase in human populations.

For example, British archaeologist Barry Kemp took a processual approach to explaining how ancient Egyptian chiefdoms became a single unified state. In 1989 Kemp suggested that a number of interacting developments gave rise to the unified state along the Nile River valley, which he dated to within a few centuries of 3000 bc. His analysis of Egyptian ceramics, religious art, and trade routes has shown that a variety of factors—including population growth, the development of new religious beliefs, and expanded trade—contributed to this important change.