When human ancestors gave up a nomadic way of life to farm the land, they gathered in small communities where they could share some of their skills.
These early societies, known as chiefdoms, sowed the seeds of modern human civilization.
     Now a unique study of archaeological data has shown that the organization and symbols of power in these chiefdoms varied greatly. Robert Drennon and Christian Peterson from the University of Pittsburgh analyzed three ancient chiefdoms that existed in different parts of the world at different points in time. The anthropologists mapped out housing patterns and counted the shards of pottery and jewelry belonging to each house. These data allowed them to unravel clues about how each society was organized.
     Writing in the journal Proceedings of the National Academy of Sciences, the scientists describe the valley of Oaxaca, Mexico, which was occupied by an early chiefdom around 3,500 years ago. Most residents lived in small villages of less than 50 people. But there was one village, San José Mogote, that had a population of more than 500. "Wealth was the most important currency for the Oaxaca community," Drennon said, referring to the high number of possessions, such as precious jewelry, found in individual dwellings.
     But the anthropologists discovered a surprisingly different kind of structure for the 3,000-year-old Alto Magdalena community in the Colombian Andes. Careful mapping of all the dwellings revealed that these people didn't live together in villages. "They were scattered across the landscape on small plots that they farmed for themselves," Drennon said. The Alto Magdalena people practiced a shamanic religion, as evidenced by sculptures found in the region of priests with supernatural and animalistic powers. Important residents were buried in the most ornate tombs, which bear religious symbols suggesting that they were revered spiritual figures. But based on the distribution of artifacts, Alto Magdalena's most powerful people were not necessarily wealthy. "High-ranking people had a great deal of spiritual power, but they didn't enjoy a much higher living status," Drennon said.
     In northeast China, Drennon and Peterson found that the structure of the Hongshan culture, which emerged around 6,000 years ago, lay somewhere between the Alto Magdalena and Oaxaca communities. "Both religion and an economy were in evidence, but they don't seem to have meshed," Drennon said.
     According to the authors, some of the differences in chiefdoms can be partially explained by landscape and climate. Both the valley of Oaxaca and the Hongshan region have dry highland climates where agriculture is a risky venture. Working together to dig irrigation channels and share labor meant people could increase their chances of success. By contrast the Alto Magdalena community had a mild climate where frosts were unheard of and crop failure was rare.
     Clifford Brown, an anthropologist at Florida Atlantic University, has done studies of settlement patterns and reached similar conclusions. "Most societies with a highly dispersed dwelling pattern tend to be in tropical forests, and the pattern may have something to do with the way the people exploit the environment," he said. But climate can't explain everything.
     Drennon says he was surprised, for example, that Oaxaca and Hongshan, both regions with relatively low population levels, would support such large, tightly integrated communities at such an early stage. Perhaps the most intriguing finding of all is the way in which each of these societies developed and persisted. In the valley of Oaxaca, chiefdoms were relatively short-lived, giving way to larger and more powerful states in a period of less than a thousand years. But in the Hongshan region and Alto Magdalena, development was much slower and chiefdoms persisted for thousands of years. To Drennon, the differences illustrate how chiefdoms with a strong economic hierarchy quickly came to dominate. Such communities probably formed the basis for much of Western civilization. But the find also shows that cultures with a spiritual-based hierarchy—or at least less emphasis on material wealth—might be more steady and stable over time.
     Writing in PNAS, the authors note that they hope other groups will be able to collect even more, similar data sets from ancient communities around the globe. Analyzing these data will help anthropologists understand the full extent of diversity between early chiefdoms, they say—and the impact such diversity has had on modern cultures.

Source: National Geographic News (8 February 2006)