WSU researchers see violent era in ancient southwest

It’s a given, in terms of numbers, the 20th Century was the most violent in history, with the American Civil War, purges and the two World Wars killing as many as 200 million people.

However, on a per-capita basis, archaeologist Tim Kohler, from Washington State University, has documented a particularly bloody period of history more than eight centuries ago on what is now American soil. Between 1140 and 1180, in the central Mesa Verde of southwest Colorado, four relatively peaceful centuries of pueblo living devolved into several decades of incredible violence.

Writing in the journal American Antiquity, Kohler and his colleagues at WSU and the University of Colorado-Boulder document how almost nine out of ten sets of human remains from that period of history had trauma from blows either to their heads of various parts of their arms.

“If we’re identifying that much trauma, many were dying a violent death,” said Kohler, whose study was funded by the National Science Foundation.

However, in the same time period, in the northern Rio Grande region of what is now New Mexico, people suffered far less violence while still experiencing similar growth and, ostensibly, population pressures. Viewed together, said Kohler, the two areas unveil a view into what motivates violence in some societies but not others. The study also offers more information about the mysterious depopulation of the northern Southwest, from a population of around 40,000 people in the mid 1200s to none just 30 years later.

From the days they first arrived in the Southwest in the 1800s, anthropologists and archaeologists have mostly downplayed evidence of a violent conflict between the early farmers in the region. A small number raised the specter of violence but lacked a good measure for it.

“Archaeologists with one or two exceptions have not tried to develop an objective metric of levels of violence through time,” said Kohler. “They’ve looked at a mix of various things like burned structures, defensive site locations and so forth, but it’s very difficult to distill an estimate of levels of violence from such things. We’ve concentrated on one thing, and that is trauma, especially to the head and portions of the arms. That’s allowed us to look at levels of violence through time in a comparative way.”

Meanwhile, Kohler and his colleagues are studying the role of factors like maize production, alteration in the climate, and growing population in changing levels of violence. Kohler’s paper published in June in The Proceedings of the National Academy of Sciences found that the Southwest experienced a baby boom between 500 and 1300 that likely exceeded any population increase on earth today.

Both in the central Mesa Verde and northern Rio Grande experienced baby booms, said Kohler, but the unusual result is that the central Mesa Verde grew more violent while the northern Rio Grande became less violent.

Kohler offers some explanations.

Social structures among people in the northern Rio Grande altered so that they identified less with their kin and more with the larger pueblo and specific organizations that span many pueblos, such as medicine societies. In addition to this, the Rio Grande had more commercial exchanges where craft specialists provided people both in the pueblo, and outsiders, with specific things they needed, such as obsidian arrow points.

However, in the central Mesa Verde, there was less specialization.

Mesa Verde National Park: WikiPedia

Mesa Verde National Park: WikiPedia

When you don’t have specialization in societies, there’s a sense in which everybody is a competitor because everybody is doing the same thing,” said Kohler. But with specialization, people are much more dependent with one another and therefore more reluctant to do harm.

Kohler and his colleagues also cite Harvard psychologist Steven Pinker’s thinking in his book, The Better Angels of Our Nature: Why Violence has Declined.

“Pinker thought that what he called ‘gentle commerce’ was very important in the pacification of the world over the last 5,000 years,” said Kohler. “That seems to work pretty well in our record as well.”

The episode of conflict in Southwest Colorado appears to have begun when the people in the Chaco culture, halfway between central Mesa Verde and northern Rio Grande, attempted to spread into Southwest Colorado.

“They were resisted,” Kohler said, “but resistance was futile.”

From 1080 to 1140, the Chaco-influenced people did well. However, in the mid-1100s, there was a severe drought and the core of the Chaco culture fell apart. A large portion of the area surrounding Chaco lost population, and in 1160, violence in the central Mesa Verde peaked. Slightly more than a century later, the area was deserted.

“In the Mesa Verde there could be a haves-versus-have-nots dynamic towards the very end,” said Kohler. “The people who stayed the longest were probably the people who were located in the very best spots. But those pueblos too were likely losing population. And it might have been the older folks who stuck around, who weren’t so anxious to move as the young folks who thought, ‘We could make a better living elsewhere.'” Older, or with too few people to marshal a good defense, the remaining people in the Mesa Verde pueblos were particularly vulnerable to raids.

At least two of the last-surviving large pueblos in the central Mesa Verde were attacked as the region was being abandoned. Some of their inhabitants most probably escaped with their lives, but, says Kohler, “Many did not.”


Contributing Source: Washington State University

Header Image Source: WikiPedia


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  • B.G. Paulus

    Wasn’t the American Civil War in the 19th Century?

    • Phil Blank

      Read it again.

      • B.G. Paulus

        “… the 20th Century was the most violent in history, with the American Civil War …”

        That seems pretty unambiguously wrong to me; the American Civil War took place from 1861 to 1865, which was in the 19th Century, not the 20th.

        My point is that including something as obviously inaccurate as that in the very first sentence unnecessarily diminishes the rest of the article.