Violence a matter of scale, not quantity, researchers show

December 11, 2017

Anthropologists have debated for decades whether humans living in tribal communities thousands of years ago were more or less violent than societies today. Researchers at the University of Notre Dame wonder if the question of more or less violence is the wrong one -- what if it's a matter of scale?

In a new paper published in Proceedings of the National Academy of Sciences, Rahul Oka, Ford Family Assistant Professor of Anthropology; Mark Golitko, assistant professor of anthropology; Susan Sheridan, associate professor of anthropology; and Agustín Fuentes, the Rev. Edmund P. Joyce, C.S.C., Endowed Chair in Anthropology, along with co-authors Marc Kissel of Appalachian State University and Nam C. Kim of the University of Wisconsin-Madison, present data showing that the size of a society's population is what drives the size of its "war group," or number of people of fighting age who defend it. They also show that the size of the war group is what determines the number of casualties in a conflict.

Specifically, the researchers show that the larger the population of a society, the smaller its war group size, proportionally -- which means fewer casualties in a conflict.

"Small-scale societies have a high proportion of their people involved in war," Oka said. "Fatalities might actually be 40 to 50 percent of the group, and definitely a higher proportion of those fighting get killed. But as we go from small-scale societies to big states and conflicts between empires or nations, fatalities rarely go above 1 percent of the group populations. So if you have 100 people fighting, you might actually get 50 people dying, combatant and non-combatant. That's 50 percent. But if you have 3 million people fighting you might get 100,000 dying, which is actually much less, proportionally, than the small-scale society. This is seen by many to suggest that contemporary large societies are less violent than past small scale societies, promoting the idea that before the state, life was nasty, brutish and short."

Instead, the researchers found that societies today are not necessarily more or less violent than past societies. The proportions are driven by a deep scaling law guiding social organization, Oka said.

Oka and his co-authors gathered data on population and war group size from 295 societies and on war group size and conflict-related casualties from 430 historical conflicts going back to 2500 B.C. They plotted the available data on population size, war group size and conflict casualties.

"We first derived the scaling laws that would explain these trends. Then we gathered the data," Oka said. "And to our very, very pleasant surprise, for both the population and army size, and army size and conflict casualties, we found the scaling laws beautifully explained the distribution."

The researchers looked at scaling, not percentages or proportions, as a reflection of the realities of warfare. As population size goes up and societies form into states, Oka said, the military becomes proportionally smaller, more nimble and more specialized. A small-scale society can have 40 percent of its population committed to fighting, for example, but "it's just economically impossible for a state-level society with, let's say, 10 million people to have an army that is 4 million strong," Oka said. "It's logistically inconceivable."

The idea of using war group size and conflict casualties as proportions of the overall group population to determine if some societies are more violent than others isn't a new one to anthropologists, Oka said.

However, this study is the first of its kind to offer an expanded data set looking at societies in different places and time periods, during both peacetime and conflict, and examining the scaling relationship between population and number of people in the army or war group, and between the number of people in conflicts and deaths occurring during conflicts.

"These scaling laws provide a means of comparing conflicts across all population scales and social and economic organizations," said Golitko. "Notably, it appears that the relative level of investment and size of conflicts have not changed much once increases in population over time are accounted for. In other words, we may be no more or less violent now than in the past."

"These are deep scaling laws that are describing the size of war groups and in turn the number of people killed in conflicts," Oka said. "Neither variable is affected by type of society or institutions. Both scale, directly and indirectly, with population. These are deeper organizational processes that have to be addressed as we continue trying to reduce conflict investment and build peace."
The paper, "Population is the main driver of war group size and conflict casualties," is available online here:

University of Notre Dame

Related Anthropology Articles from Brightsurf:

Study finds field of forensic anthropology lacks diversity
The field of forensic anthropology is a relatively homogenous discipline in terms of diversity (people of color, LGBTQ+ individuals, people with mental and physical disabilities, etc.) and this is highly problematic for the field of study and for most forensic anthropologists.

Neandertal gene variant increases risk of severe COVID-19
A study published in Nature shows that a segment of DNA that causes their carriers to have an up to three times higher risk of developing severe COVID-19 is inherited from Neandertals.

How do Americans view the virus? Anthropology professor examines attitudes of COVID
In her latest study, Northern Arizona University professor Lisa Hardy looks at how Americans' attitudes and responses have changed during the time of the pandemic and how to many people, the virus is not a biological agent but instead a malicious actor.

Neandertals may have had a lower threshold for pain
Pain is mediated through specialized nerve cells that are activated when potentially harmful things affect various parts of our bodies.

Running in Tarahumara culture
Running in Tarahumara (Rarámuri) Culture. The Tarahumara (Rarámuri) are a Native American people from Chihuahua, Mexico, who have long been famous for running, but there is widespread incredulity about how and why they run such long distances.

The growing pains of orphan chimpanzees
Using long-term behavioral and hormonal data from wild chimpanzees in the Taï Forest, Côte d'Ivoire, researchers from the Taï Chimpanzee Project at the Max Planck Institute for Evolutionary Anthropology, have revealed that mothers may be shaping pre-adult growth and offspring muscle mass even without direct provisioning.

Caribbean settlement began in Greater Antilles, say University of Oregon researchers
A fresh, comprehensive look at archaeological data suggests that seafaring South Americans settled first on the large northernmost islands of the Greater Antilles rather than gradually moving northward from the much closer, smaller islands of the Lesser Antilles.

Human songs share universal patterns across world's cultures
From love songs to lullabies, songs from cultures spanning the globe -- despite their diversity -- exhibit universal patterns, according to a new study.

Skull features among Asian and Asian-derived groups differ significantly
Forensic anthropologists have now discovered that several skull features in Asian and Asian-derived groups differ significantly with regard to shape, such that they can be distinguished using statistical analyses.

Skull dimensions of Dominicans and Haitians differ despite close physical proximity
Researchers from Boston University School of Medicine (BUSM) have conducted a craniometric study (measuring the main part of the skull) on understudied and marginalized groups and found that skull dimensions of Dominicans and Haitians, who occupy a relatively small island of Hispaniola, are different from each other.

Read More: Anthropology News and Anthropology Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to