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Washington State University
CAS Connect February 2016

Why do we wage war?

Despite the enormous costs to society, humans continue to fight and kill each other with ever-increasing efficiency.

Anthony Lopez

WSU political scientist Anthony Lopez thinks there may be an evolutionary basis to our hostility. He studies the role warfare has played in human evolution.

In a recent paper published in the journal International Theory, Lopez proposes that the modern day social, moral, and political intuitions about how people ought to behave when their group or country is threatened are likely the result of evolved psychological adaptations to a much earlier and warlike lifestyle.

In other words, while modern warfare bears little resemblance to the hand-to-hand combat of humanity’s hunter-gatherer ancestors, many of the underlying reasons we fight remain the same.

“When we examine warfare from an evolutionary perspective, it becomes evident that there are very basic and recurrent dynamics that have motivated groups of humans to commit violence against each other throughout history,” Lopez said. “The more we learn about these underlying neurological motivations and how they developed, the more capable we will become at identifying new ways to deescalate conflicts.”

Violent by design

Across Africa and Eurasia, archaeologists have discovered evidence of human-against-human violence dating back hundreds of thousands of years. Our early ancestors fought each other over territory, mates, and resources. According to established research, the genetic information responsible for aggression was passed down through each surviving generation in an evolutionary process known as natural selection.

Charles Robert Knight [Public domain], via Wikimedia Commons
“Le Moustier” by Charles Robert Knight [public domain]. Photo via Wikimedia Commons
While a tremendous amount of research has been conducted on the evolution of anger and aggression between individuals, especially in humans and primates, the origins of group conflict, or war, and how it influenced early brain development remain a point of contention among evolutionary scholars.

From his examination of new archaeological evidence and advancements in neuroscience, Lopez believes humans possessed the cognitive tools to work together in waging war long before the advent of agriculture and settled communities, which occurred around 12,000 B.C.E.

For these early humans, warfare would have been reproductively worthwhile because the benefits of expanded territory and access to mates would have outweighed the upfront loss of life for the victors, Lopez says. And over tens of thousands of years, those groups of early humans that cultivated forms of social cohesion and identity to rally around would have prevailed in conflicts over other groups that lacked relative social skills and cooperation.

“Humans evolved a tendency toward aggression outside the group but cooperation within it because it benefited their long-term chances of survival and reproduction,” Lopez said. “Over a long enough timeline, this tendency of within-group solidarity against an outside threat evolved into the set of psychological adaptations that humans use today to solve challenges related to war.”

Adaptations for war

One of these adaptations is the concept of sacred values or symbols. From an evolutionary perspective, ancestral humans developed shared sacred values as a way to strengthen bonds within groups and increase solidarity in the face of danger.

Although the issues, objects, and symbols that groups hold as sacred vary tremendously across space and time, the nature of sacred values and people’s reactions to their violation are cross-culturally universal.

By PICASSO, la exposición del Reina-Prado. Guernica is in the collection of Museo Reina Sofia, Madrid, via Wikipedia.
Pablo Picasso’s “Guernica,” 1937, depicts Nazi bombing of the Basque town during the Spanish Civil War. Photo via Wikipedia.

Lopez believes this ancestral adaptation correlates directly with the way modern humans instinctively categorize themselves and others with unique symbols or beliefs that represent their identity. Sacred values need not be religious, but when they are, the predicted consequences of violating them are greater.

Many modern-day terrorist groups, such as ISIS and the Taliban, stick together and continue to fight despite numerical and technological disadvantages because they share sacred values, Lopez said.

“Sacred values are an important component of being a human in a community. Many of the individuals who are leaving the comforts of an American or European life to go and join a group like ISIS are seeking a communal identity that promises purpose and social meaning,” Lopez said. “These are very basic desires that we can understand and that help to explain radicalization.”

The psychological drive for revenge is another example of an ancestral human adaptation with an evolutionary impact, Lopez said. Research in neuroscience shows that the prospect of inflicting retaliatory punishment triggers pleasure centers in the brain.

Indeed, the desire for revenge has led to some of human history’s most infamous wars.

“Hitler’s rise to power is a well-known example of the ability of revenge to compel large-scale violence. And the very foundations of American identity have been shaped by its public reaction to various events, such as the surprise attack on Pearl harbor and the terrorist attacks of September 11, 2001,” Lopez said.

Evolutionary theory in international relations

Using evolutionary theory as a way to understand the enemy is a growing trend in international relations, Lopez said. After decades of intractable, overseas conflicts, the U.S. Department of Defense is now working with social and neuro-scientists to understand not only the enemy’s intentions but also their psychology.

F-16A, F-15C and F-15E flying during Desert Storm. (U.S. Air Force photo)
F-16A, F-15C and F-15E flying during Desert Storm. Photo: U.S. Air Force

“In the past, international relations scholars and policymakers tended to write off the behavior of our enemies as irrational,” he said. “We are now starting to recognize that their motivations are actually very understandable. My hope is that policymakers will continue this trend of trying to understand our enemies’ psychology as well as their intentions. It is a new and important step in international relations.

“A deeper understanding of the role of revenge in international relations could provide U.S. policymakers with clearer guidance at times when our human psychology is specifically designed to cloud rather than clarify the costs and benefits of responsive action.”