The debate continues as to whether war extends deep into human pre-history. This tends to break down into two camps: (1) the “deep roots” advocates, who argue that inter-group aggression extends to the origins of our species (or perhaps even earlier), and (2) those who propose that hunter-gatherers were essentially peaceful until the advent of agriculture. 

On his website “Why Evolution is True,” Jerry Coyne has been summarizing the various critiques that deep-rooters like Steven Pinker and Michael Shermer have been piling on against the science writer John Horgan, who has argued that war is a recent innovation.

I think the reason for all the confusion is that the best way to resolve the debate is to have a systematic review of the archaeological record. Of course, that is very hard to do, since there are gaps in what we know about the past, and not all humans leave traces of their existence. But the public debates often encourage cherry-picking of the data, sometimes highlighting prehistoric groups that show signs of intergroup violence (and they did exist), or at other times highlighting peaceful groups (so did they!). Rarely is there a systematic, big-picture approach. 

In an essay I wrote last year, “Genocidal Altruists,” I took a different approach, arguing that our ancestors were complex. I cited the archaeologists Jonathan Haas and Matthew Piscitelli, who actually did attempt a systematic review. To quote myself… 

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“However, the most obvious and direct way to understand violence in our prehistoric past is through the archaeological record. There are clear examples of skeletal trauma indicating that interpersonal and group-level violence appeared in prehistory well before modern nation-states. Our ancestors were not complete peaceniks. Like us, they were complex.

But this is a far cry from saying that war has been unending since the beginning of humanity. In fact, violence seems to have been relatively rare before the increasing populations densities and fixed settlements that accompanied agriculture. In a thorough review of prehistoric violence, the archaeologists Jonathan Haas and Matthew Piscitelli wrote, with emphasis, that:

“globally, at least 2,930 skeletal remains of Homo sapiens have been recovered at over 400 archaeological sites dating prior to 8000 BC/10000 BP… the small number of skeletal finds mentioned above showing ambiguous signs of conflict come from a comparatively small number of sites. Rather than demonstrating the commonness of ancient warfare among humans, consideration of the entire archaeological data set shows the opposite… The archaeological record is not silent on the presence of warfare in early human history. Indeed, this record shows that warfare was the rare exception prior to the Neolithic pressures of population densities and insufficient resources for growing populations” (2013: 182-3, emphasis added).

Prior to agriculture, there were several reasons that mobile hunter-gatherers would have little incentive to engage in warfare. These include small group sizes, an egalitarian social structure, kin and social ties to neighboring groups who were a source of mates and trade, low population densities that allowed easy mobility to new territory should tensions arise, and the relative lack of accumulated wealth that could be an incentive to attack one’s neighbors (see Fry and Söderberg 2013’s appendix for a fuller list).”

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So, who’s right?  I think it’s a little of both and a little of neither. If we take the archaeologists as the experts here, then I think that Pinker, Shermer, and Coyne are a bit too dismissive of Horgan’s main point about the relative infrequency of prehistoric war. I won’t defend all of what Horgan says, such as his point that the “deep roots” hypothesis encourages a fatalistic acceptance of war. Some people might see it that way, but that’s just one interpretation.

Perhaps the main lesson is this: When in doubt about human prehistory, ask the archaeologists. 

References

Fry D, Söderberg P. 2013. Lethal aggression in mobile forager bands and implications for the origins of war. Science 341(6143): 270-273.

Haas J and Piscitelli M. 2013. The prehistory of warfare, In War, Peace, and Human Nature. Pp. 168-90 in: D Fry (ed.) Oxford University Press.