You've probably noticed how violent humans can be and how violent humans have been throughout our history. Why? Well, maybe violence has been a key facet of our species' evolution. Many have suggested that violence has driven evolution but a new theory puts a new twist on it: violence created a means by which smart humans could overcome strong humans.
Human social organization is not at all like the social organization of our primate relatives. It may be that the development of weapons played an important role in the changes necessary to, eventually, bring about the social, cultural, and political orders which underlie human civilization.
Ironically, weapons of violence may have laid the foundation for this, but ultimately it's cooperation rather than conflict which it had to create.
Whenever it occurred, the invention of projectile weapons influenced the evolution of our ancestors. The upper body of chimps is adapted for swinging through trees. Throwing requires a different organisation of the torso, arm and hand, along with the brain circuitry that underpins coordination of arm movements, adaptations that were selected in our ancestors.
Throwing skill became the defining human characteristic, evolutionary biologist Paul Bingham and psychologist Joanne Souza of Stony Brook University in New York argue in their 2009 book, Death from a Distance and the Birth of a Humane Universe. They place throwing on a par with the cheetah's capacity to run, and believe that it made social cooperation inevitable: once humans could kill from a distance, no individual could rule by strength alone.
Without an alpha male imposing order, our ancestors needed new behaviour to ensure social cohesion. Studies of modern egalitarian societies indicate that a key development was the emergence of strict social norms, including the punishment of "free riders".
The Turkana, nomadic cattle herders in East Africa, lack a centralised government yet can successfully raise large raiding parties of warriors who are not kin and often do not even know each other. Sarah Mathew at Stony Brook University and Robert Boyd at Arizona State University in Tempe found that the Turkana produce this cohesion, at least in part, by punishing cowardice and desertion with public floggings and fines (PNAS, vol 108, p 11375).
So, group living begat hunting, hunting spurred the development of weapons technology, and new weapons overthrew the alpha male and led to the emergence of cooperative tendencies. It's a neat story, but are lethal weapons really necessary to explain the transition from hierarchies based on brute strength to egalitarian living?
At the forum, Carel van Schaik, who directs the University of Zurich's anthropology institute in Switzerland, noted that in hunter-gatherer societies, individuals are extremely reliant on one another, especially if they become ill or cannot provide food for themselves for any reason. "Because of this interdependence, you just can't afford to be too bossy," he said.
Perhaps, then, early hunter-gatherer societies had to be egalitarian simply to survive. This possibility is weakened by recent discoveries about how chimps behave in the wild. Like our ancestors, they hunt collectively, share meat and care for their sick. But the one thing they do not do is wield lethal projectile weapons. Although chimps have been known to use stone tools, to crack nuts for example, they cannot throw them with any precision. And they continue to live in hierarchies dominated by beefy alpha males.
Source: New Scientist, October 13, 2012
All of this changed again, though, when farming developed. Farming allowed for individuals and families to accumulate great wealth. That, in turn, allowed them to hire others to help protect that wealth, thus making it possible for new bullies and alpha males to be created. Rather than being reliant entirely on raw physical strength, though, bullies were dependent upon being born to the right families at the right time.
So social orders came to be dependent upon wealth, its efficient use, and acquisition through exploitation rather than voluntary cooperation. That, in turn, allowed for the creation of modern states. It was the advent of new weapons technology, the gun, which forced despotic leaders to cede some of their power to the people because these weapons gave people the ability to take away the basis for the power of the wealthy, which is their wealth.