From the very first spear to nuclear bombs, deadly weapons have directed the course of our cultural evolution
IT’S about 2 metres long, made of tough spruce wood and carved into a sharp point at one end. The widest part, and hence its centre of gravity, is in the front third, suggesting it was thrown like a javelin. At 400,000 years old, this is the world’s oldest spear. And, according to a provocative theory, on its carved length rests nothing less than the foundation of human civilisation as we know it, including democracy, class divisions and the modern nation state.
At the heart of this theory is a simple idea: the invention of weapons that could kill at a distance meant that power became uncoupled from physical strength. Even the puniest subordinate could now kill an alpha male, with the right weapon and a reasonable aim. Those who wanted power were forced to obtain it by other means - persuasion, cunning, charm - and so began the drive for the cognitive attributes that make us human. “In short, 400,000 years of evolution in the presence of lethal weapons gave rise to Homo sapiens,” says Herbert Gintis, an economist at the Santa Fe Institute in New Mexico who studies the evolution of social complexity and cooperation.
The puzzle of how humans became civilised has received new impetus from studies of the evolution of social organisation in other primates. These challenge the long-held view that political structure is a purely cultural phenomenon, suggesting that genes play a role too. If they do, the fact that we alone of all the apes have built highly complex societies becomes even more intriguing. Earlier this year, an independent institute called the Ernst Strüngmann Forum assembled a group of scientists in Frankfurt, Germany, to discuss how this complexity came about. Hot debate centred on the possibility that, at pivotal points in history, advances in lethal weapons technology drove human societies to evolve in new directions.
The idea that weapons have catalysed social change came to the fore three decades ago, when British anthropologist James Woodburn spent time with the Hadza hunter-gatherers of Tanzania. Their lifestyle, which has not changed in millennia, is thought to closely resemble that of our Stone Age ancestors, and Woodburn observed that they are fiercely egalitarian. Although the Hadza people include individuals who take a lead in different arenas, no one person has overriding authority. They also have mechanisms for keeping their leaders from growing too powerful - not least, the threat that a bully could be ambushed or killed in his sleep. The hunting weapon, Woodburn suggested, acts as an equaliser.
Some years later, anthropologist Christopher Boehm at the University of Southern California pointed out that the social organisation of our closest primate relative, the chimpanzee, is very different. They live in hierarchical, mixed-sex groups in which the alpha male controls access to food and females. In his 2000 book,Hierarchy in the Forest, Boehm proposed that egalitarianism arose in early hominin societies as a result of the reversal of this strength-based dominance hierarchy - made possible, in part, by projectile weapons. However, in reviving Woodburn’s idea, Boehm also emphasised the genetic heritage that we share with chimps. “We are prone to the formation of hierarchies, but also prone to form alliances in order to keep from being ruled too harshly or arbitrarily,” he says. At the Strüngmann forum, Gintis argued that this inherent tension accounts for much of human history, right up to the present day.
Boehm’s belief that we have inclinations towards both hierarchical and egalitarian social structures is strengthened by research published last year by Susanne Shultz at the University of Oxford and colleagues. They looked at the social structures and genetic relatedness of 217 living primate species. Their analysis revealed a range of organisations from solitary living to complex social structures, and showed that the closer two species were genetically, the greater the similarity between their social structures (Nature, vol 479, p 219).
If our ancestors were once hierarchical like chimps, how did they develop a different political structure? Gintis sees the transition to group living as the watershed, because it allowed primates to cooperate to share large animal kills. Species of Australopithecus that lived 3 or 4 million years ago were probably scavengers, but they may have thrown stones to chase off predators. “We know that australopithecines aggregated stones and moved them about,” he says.
At some point, hominins took up hunting and invented weapons that could kill from afar. The world’s oldest spear was found by archaeologist Hartmut Thieme in an opencast mine in Germany in the 1990s, along with two others like it, as well as horse, elephant and deer remains. However, it is possible that such weapons were produced far earlier than 400,000 years ago, because the archaeological record is patchy and wood perishes easily.
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).
Cooperate or die
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.
Whatever allowed our ancestors to break free of hierarchical rule, egalitarianism proved remarkably successful, lasting for hundreds of thousands of years. Then, about 10,000 years ago, there was another massive political upheaval. The immediate catalyst was the invention of farming, and the increased trade it allowed. The result was a change in the way weapons were deployed. “As soon as you get accumulated wealth,” says Gintis, “then individuals can monopolise that wealth and incentivise others to protect them.” This led to a new kind of hierarchy dominated by a “Big Man” who did not need to be physically strong, just rich enough to pay a small cabal of armed and trusted subordinates to protect him.
In this way, human societies entered an age of rampant despotism. Those at the top exploited those lower down - making slaves of them, demanding taxes and so on. But they also protected them from outsiders, so the system was stable for as long as the threat of the enemy outweighed the inhumanity of the exploitation. Less stable, however, was the fate of despots, relying as it did on the risky strategy of buying the loyalty of others. “They didn’t often die in their sleep, let’s put it that way,” says Gintis.
Such wealth-based hierarchies were the seeds of the modern state. And from small beginnings, these proto-states grew, spurred at least in part by another innovation in weapons technology. Horses were domesticated about 5500 years ago, but it wasn’t until about 1000 BC that nomads on the Eurasian steppes learned how to sit on them and how to control them. Now men were able to shoot iron-tipped arrows from small, powerful bows while mounted. The combination of horse and armed rider, according to Peter Turchin at the University of Connecticut in Storrs, was arguably the first weapon of mass destruction.
The first WMD
"This technology dramatically increased the scale of warfare, making it much more offensive," Turchin told the forum. To improve their chances of survival, groups under threat coalesced into larger, more defendable societies. Turchin even suggests that today’s major religions emerged at around this time, in response to the need to create social cohesion between disparate ethnic groups. "These religions allowed sociality to break through the barriers of ethnicity," he said. The nation state was born, and its weapon of choice was the cavalryman.
With so much firepower now available, you might expect this to have been a bloody phase of human civilisation. In fact, the opposite is true, says Samuel Bowles, an economist at the Santa Fe Institute. His calculations, based on archaeological and ethnographic data, suggest that even in the 20th century - the “century of total war”, as it has been called - warfare accounted for about 5 per cent of mortality in Europe, just half that for Stone Age Europeans and today’s egalitarian hunter-gatherer societies (Science, vol 324, p 1293). The nation state proved particularly good at winning wars and protecting people, he concludes, and that explains why it has been the dominant social model for the past 500 years.
If despotic, power-based hierarchies worked so well, what caused latter-day Big Men to cede some of that power in the form of democracy? Again, it was a response to new lethal weapons, says Gintis. Starting with the invention of the flintlock musket in the 17th century, handgun technology evolved until, by the early 20th century, armed foot soldiers finally had the edge over cavalry. In other words, guns had put power back into the hands of the masses. Now leaders were reliant for their protection on a sector of society that was disenfranchised and potentially disgruntled. If Gintis is correct, extending the vote to most of the population was the price the elite paid to buy their support.
This pattern continues today, says Bingham. Democratisation tends to go hand in hand with the citizens of a country gaining access to weapons, usually handguns, and thereby breaking the state’s monopoly on coercive threat. Another modern technology has also helped our anti-hierarchical tendencies get the upper hand. The challenge, just as it was millions of years ago, is to coordinate the majority, which is why real-time social media have become powerful drivers for democracy - as the Arab Spring showed. “Even armed merely with stones and other simple weapons, large, well-coordinated majorities have significant coercive clout,” says Bingham.
The gradual elimination of despots has been one of the major political trends of the past century. So are we headed for universal democracy? Gintis believes there is no room for complacency. Torn as humans are between hierarchical and anti-hierarchical instincts, open societies will always be threatened by the forces of despotism. Boehm agrees. “It boils down to whether a government can establish fear, rather than consensus, as its basis,” he says. “And with humans, this will always be up for grabs.”
To democracy and beyond
If innovations in weapons technology have driven the emergence of civilisation (see main story), the obvious question is, what next?
The past 70 years have seen the rise of the megaweapon, including nuclear, biological and now cyberweapons. According to Paul Bingham and Joanne Souza of Stony Brook University, New York, these have enforced a kind of crude democracy between nations, giving coalitions of states a credible threat to help keep “rogue” states in check. “There is no other route to global cooperation than precisely this kind of coercive equilibrium. Nor will there ever be in the future,” Bingham says.
Because democratic states tend to be wealthier than authoritarian ones, they can afford more megaweapons, which explains why internationally the coercive push has been away from autocracy, towards democracy. Within a state, however, megaweapons offer no one sector of society any power over another, so they have little effect on social structure. At the national level, it is individual weapons - and guns in particular - that influence the balance of power. According to Bingham and Souza, the more successfully a state’s security bodies monopolise access to guns, the more authoritarian that state will be. That’s why they argue that democracy begins with the democratisation of arms.
In the future, however, a new advance in weapons technology could set civilisation on a novel track. “A technology could easily arise that irremediably places democracy on the defensive,” says Herbert Gintis at the Santa Fe Institute in New Mexico. He gives the example of an implant with the capacity to inflict pain on, or gather information about, an implanted individual. Such technology is already conceivable, he says. How it might influence the future of human social organisation is not.
Laura Spinney is a writer based in Lausanne, Switzerland