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Friday, October 19, 2012

The Role of Weapons in Human Evolution

The New Scientist has an article about a theory that human physical and cultural evolution was driven, at least in part, by the development of weapons. From the article:
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.

. . . 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.
 The theory goes on to posit that after humans developed agriculture--allowing the accumulation of wealth--then power tended to be ceded to the despot with the goods necessary to pay troops or an army. However, it did not stop at despotism. The development of firearms spurred democratic societies. From the article:
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."
The Second Amendment was truly inspired.

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