From humankind’s long history of violence, two chapters have come under the scrutiny of Washington State University researchers that point the way to a more peaceful world.

Tim Kohler, who has spent four decades pondering the people of the ancient southwestern United States, saw violence drop in one sector of the region as its people took up a sort of “peaceful commerce” with other groups. And Jutta Tobias ’06 MS, ’08 PhD, after helping Rwandan coffee farmers use computers to broaden their customer base, found they eventually came to think more charitably about people with whom they had been in conflict during the brutal ethnic violence of 1994. She thinks of it as an example of “transformative entrepreneuring.”

Call it what you will, but it’s a remarkable concept, particularly when one considers that it emerges from a history replete with savagery. Writing in The Better Angels of Our Nature, Steven Pinker catalogs the bloodletting that has been commonplace through the ages: the stone points found in ancient corpses like Kennewick Man, the slaughtered men and enslaved women of Homeric Greece, and the brutality of God and other major figures in the Bible, which Pinker calls “one long celebration of violence.”

For the Romans, “crucifixion was a common punishment” and half a million people died to put bottoms in the Colosseum seats. Acts of extreme violence populate one in four pages of the medieval romance Lancelot. Several American statesmen dueled with pistols, not just Aaron Burr and Alexander Hamilton, and the twentieth century’s death toll runs to around 200 million.

So if someone sees a method to get out of this madness, it’s worth considering.

Kohler, a Regents professor of anthropology, has glimpsed it among the mysteries and surprises of the pre-colonial Southwest. For four decades now, he has pondered why the Mesa Verde area had some 40,000 people in the mid-thirteenth century who almost completely disappeared over 30 years.

Last summer, he reported that nearly nine out of ten sets of human remains from 1140 to 1180 had signs of trauma, particularly to the arms and head. It was a bloody time, one of the bloodiest known in North America. But less than 300 miles to the southeast, in the northern Rio Grande region of what is now north-central New Mexico, the proportion of traumatized remains was one-third of what researchers saw around Mesa Verde. Both places had housed two of the densest pre-Hispanic Pueblo populations in the region’s history, but the northern Rio Grande saw far less violence, even as new people were coming from the north.

Writing in the prestigious archaeological journal American Antiquity, Kohler and several colleagues surmised that the northern Rio Grande grew more peaceful through changing social structures and organizations. People identified less with their immediate kin and more with groups, like medicine societies, that spanned several pueblos. Craft specialists developed new ceramics and traded them across longer distances. Obsidian traded for bison meat and hides ended up hundreds of miles away on the Great Plains.

In earlier times, when most everyone was a hunter or farmer, “people were pretty redundant,” says Kohler. But by the early 1300s, different people with different skills were central to a better, commerce-driven way of life.

“You actually come to depend on people that you’re going to be exchanging that stuff with for your livelihood,” says Kohler. “They’re probably not somebody that you want to hit on the head, because you’re making your livelihood at least in part off of them.”

The American Antiquity paper borrows its title from Pinker’s Better Angels and cites him repeatedly.

Once people “are enticed into voluntary exchange,” Pinker writes. “they are encouraged to take each other’s perspectives to clinch the best deal (‘the customer is always right’), which in turn may lead them to respectful consideration of each other’s interests, if not necessarily to warmth.”

Tobias caught a glimpse of that several centuries later and halfway across the world. In 2006, she was tapped by Colleen Taugher, a project associate for the WSU International Research and Agricultural Development Office, to help Rwandan coffee growers get on the Internet when they came to a village to wash beans. Some of the people she worked with were “genocide widows” whose husbands were among the hundreds of thousands killed in ethnic violence in 1994.

Returning to the United States, she turned her experience into a doctoral dissertation, surveying coffee growers and finding they were starting to collaborate with people who may have been enemies two decades earlier.

To be sure, her questioning had to be approved by the government and she had to step lightly around the issue. “Talking about ethnic relationships is officially not allowed by [President Paul] Kagame’s government. So you couldn’t directly ask somebody, ‘How do you like the Hutu?’ because according to Kagame, it would have been an offense,” she says.

But using symbols on paper and secret ballots, Tobias and her student assistants managed to ask if coffee farmers were starting to collaborate with members of the other ethnic group, “and that’s what the finding was.” It helped that the coffee growers, who make between $120 and $150 a year, were on average making $50 more through expanded market opportunities.

“If everybody’s dirt poor but you ended up having an economic opportunity, that is a social lubricant,” said Tobias, now a lecturer at Cranfield University in England. “Economic opportunity in a desperate poverty setting acts as a social lubricant.”