Who remembers Robert Ardrey? I must shamefully confess that I was a fan back in the 1970s, when the ‘killer ape’ hypothesis was in the air. This was the idea that one of the things that made humans different and drove the evolution of the human brain was aggression and competition, specifically that big brains evolved as a weapon in a multi-million year intra-specific arms race. Arms races are cool concepts that, when first introduced to natural selection, seem like powerful mechanisms to drive the evolution of elaborate features.
I outgrew Ardrey, have no fear. As I learned more biology, I came to mistrust those umbrella hypotheses that appeared to explain everything with one simple premise — biology is complicated, and rarely fits into those simple categories. I also began to get suspicious of poorly credentialed popularizers who too often seemed most adept at twisting research to fit whatever hobby horse they were riding at the time (see also Elaine Morgan).
But mostly, it didn’t fit what we see in the real world. Think about your interactions with other human beings: probably, unless you’re in the military, the most ferociously antagonistic conflicts you encounter involve commenting on Pharyngula. The internet has a reputation for being contentious, but get real: it’s slinging words back and forth, feelings might get hurt, but the consequences to your survival and mating prospects are very, very low. You could even argue that most of the jostling isn’t about destroying our enemies, but about increasing in-group solidarity.
It’s even more true outside the abstract world of the internet. Most of our interactions with other people are regulated by deep-down protocols that we’re socialized into — if someone cuts into a queue ahead of you, we don’t pull out a stone axe and take care of the problem, we either roll our eyes and acquiesce or we complain verbally and get other people to shame the interloper. It’s relatively harmless. We go to work, and maybe you share an office with annoying jerks (of course you do, we all do), but we don’t go on a rampage and fight the boss for dominance, so we can purge the tribe of the ones we detest, who borrow our stapler and don’t give it back — no, we grumble and accommodate and cope somehow, and maybe try to work our way into a better position with social networking.
It’s what we are. We are social animals. In the history of our species, I think the most important signature of our evolutionary history is the construction of cohesive social units, groups larger than the individual, that allow us to survive better together than alone. We aren’t warring animals, we’re cooperative animals.
War is a byproduct. We’ve evolved and enculturated mechanisms that allow groups of increasingly larger size to persevere — a paleolithic tribe of 30 people is one thing, a nation of hundreds of millions or billions is another — and war occurs when these groups bump into one another. War is not the central activity of the human species, though, but a fringe event, a side-effect of processes that reinforce group cohesion and secondarily create friction when diverse social units encounter one another and demand responses that aren’t so strongly reinforced within our groups.
Anyway, that long ramble is an introduction to an interesting article on the history of war in primates. It’s just not that common in our closest relatives, the chimpanzees, and recent accounts of coordinated gang attacks may be unusual responses to high environmental stresses. This is not a good time to be a chimpanzee.
There are known examples of death by lethal tools in the human archaeological record, and this isn’t an argument that everyone since the dawn of time has been living in peaceful coexistence, but the documentable evidence of war is very thin. People are lovers, not killers.
Archaeologist Jonathan Haas of the Field Museum in Chicago concurs: “There is a very tiny handful of incidences of conflict and possible warfare before 10,000 years ago. And those are very much the exception.” In an interview with me he attributed the emergence of warfare in prehistory to growing population density, diminished food sources and the separation of people into culturally distinct groups. “It is only after the cultural foundations have been laid for distinguishing ‘us’ from ‘them,’” Haas says, “that raiding, killing and burning appear as a complex response to the external stress of environmental problems.”
On the other hand, Haas adds, “groups that are at war in one era or generation may be at peace in the next.” War’s recent emergence, and its sporadic pattern, contradict the assertion of Wrangham and others that war springs from innate male tendencies, he argues. “If war is deeply rooted in our biology, then it’s going to be there all the time. And it’s just not,” he says. War is certainly not as innate as language, a trait possessed by all known human societies at all times.
That’s the good news: warfare is a pathological condition for our species, brought on by external stress. We are not biologically committed to fighting one another.
The bad news is that external stresses are growing, with increasing demands for oil and water and food, with looming climate change likely to disrupt environmental stability, and with overpopulation increasing the friction within and between groups. Brace yourselves.
I might suggest, though, that the greatest human successes have arisen from developing tools to strengthen social unity and encourage competition — killing your neighbors is a sign of failure.