On the Nature of Violence
Kin, Clan, Conflict
I do know that humans, like the smart apes they are, have an elaborate hierarchy of affiliations. There is kin—immediate and extended family—and close behind that, neighbors, members of my social group, people to whom I can turn in need, people like me. Because we live a largely sedentary lifestyle (as opposed to being constantly nomadic, that is), this "neighbor" group is often defined by various kinds of physical proximity: living next door, going to the same schools, working in the same office, or shopping in the same grocery store. As we travel, go to work, go away to school, move here or there for various reasons, we add new layers of relatedness beyond those who occupy our original home turf. Going home is a terribly important concept to Americans, but lots of us have multiple "homes."
And finally, being clever primates with large brains, we add layer upon layer of fictive kin or neighbors based on abstractions. We regard as close to us those who share our beliefs or our interests, whose hobbies, music, sports, religions, passions and occupations coincide with ours. And here is where things get complicated.
Once upon a time about 40,000 years ago, two new phenomena appeared that were to leave traces in the long archaeological record of our past. The first was a new kind of entity called an aggregation site. For the first time ever, bands of humans (loose affiliations of related individuals) began to meet with other such bands regularly. Archaeological sites preserve remains of gatherings of unprecedented size, where lots of groups came together and stayed for a period of time. It is not difficult to imagine these aggregation sites as being the remnants of events much like swap meets or flea markets prolonged into weeks or maybe months. We know from the preserved artifacts that people came from many miles around, presumably to exchange the valuable goods local in their area for ones found in another. And we imagine that some hoped to find mates from another group that was appropriately distant (not incestuous) and yet acceptably close (not too foreign). Before the appearance of aggregation sites, population densities were apparently so low that bands would run into perhaps only one or two other local bands in an individual's entire lifetime. The appearance of aggregation sites marks a real change in the experiences of individuals and in the extent to which they experienced novelty.
Because humans began to see strangers for the first time, the second phenomenon appeared. That took the form of items of personal adornment: crude jewelry, probably body paint and tattooing, and utilitarian objects and clothing that were decorated in the style of one's home group. These objects were ways of declaring an affiliation with a particular group; wearing them was a way of saying "I am from the people who hunt reindeer at the river crossing in the cold woods" or "I am a shoreline person who gathers mollusks for food and makes their shells into adornments." There was no need for such emblems—colors, in the modern parlance of urban gangs—when you never met anyone who had not known of you or your kin from the time of your birth. Once there were strangers, there was a new need to strengthen and publicly proclaim affiliations. These were the first steps to war.
Anthropologists have argued that war itself arose only after humans were tied to the land, after the invention of agriculture. A family who has cleared a field, seeded it, and tended and watered the growing plants has a large investment of time and energy in that particular piece of land, and that crop. There is a reason for defense of territory far beyond the need experienced by hunter-gatherers who travel regularly over large ranges. But long before the invention of agriculture at about 12,000 years ago, there were social groups and strangers, there was Us and Them. Making that distinction lies at the heart of all violence within our species. It is a much more ancient propensity than agriculture. Even chimpanzees and other primates at times resort to fatal violence against their own kind.