Writing in Scientific American, John Horgan states, “10,000-Year-Old Massacre Does NOT Bolster Claim that War Is Innate. A new report on a massacre of hunter-gatherers in Africa is consistent with the claim that war, far from being an inborn trait that evolved millions of years ago, is a recent cultural invention.”

What does it mean to call war an “innate behavior” or an “inborn trait”? This is an old-fashioned way of saying that some behavior is genetically determined. Actually, modern biologists stop using such terms quite a while ago. We now understand that human behavior is molded by a complex mixture of genetic predispositions, environmental influences, and culture (and don’t forget the key role that culture plays in shaping human behavior—for an excellent review of cultural evolution see Joe Henrich’s book The Secret of Our Success).

Furthermore, war is not individual behavior. How can you as a person have the trait of war, in isolation from other human beings? Even one group cannot have war; it takes two or more groups of people. So the whole framing of the debate as “Is War Innate?” is completely unhelpful. John Horgan should know better.

The debate over war (or War Over War, as I have referred to it in previous posts) is very important. We all want to eliminate war, but the best way to do it is not by wishing it away, but by using science to understand its evolution and the causes that make it wax and wane. This is one of the central concerns in my recently published book, Ultrasociety: How 10,000 Years of War Made Humans the Greatest Cooperators on Earth.

Below is an excerpt from Ultrasociety, in which I review the debate on war before states arose, and reject both the extreme position of John Horgan and the opposite extreme (currently occupied by Steven Pinker).

==========================================================

Excerpt begins:

What do we know about the incidence and intensity of war before the states arose?

Many of my readers will know that this is an extremely controversial question. There is a bitter ‘war over war’ in academia, which periodically spills over into the blogosphere and popular magazines. Because my conclusions critically depend on the answer to this question, I also need to enter this contested field.

There are two extreme positions, neither of which makes sense to me. The first one is the myth of the peace-loving “noble savage” of Jean-Jacques Rousseau. Even when these savages fought, their wars were somehow non-lethal and non-serious, even comic affairs (according to the Eurocentric notions of ‘primitive war’ that we discussed earlier).

The myth of peaceful savage was demolished by Lawrence Keeley in his ground-breaking book, War Before Civilization. Keeley writes, in particular, of how archaeologists “pacified the past” by refusing to see evidence of prehistoric warfare, sweeping such evidence under the rug when it “stared them in the face.” He collected data from archaeological and ethnographic sources and demonstrated that death rates (in other words, the probability of being killed in war) were an order of magnitude higher in pre-state societies than in our own.

The opposite extreme is the view that the distant human past was an unrelenting Hobbesian “war of all against all.” This position has been recently occupied by the psychologist and author of popular books Steven Pinker in The Better Angels of Our Nature: Why Violence Has Declined. Here’s how Pinker starts Chapter 1, A Foreign Country:

If the past is a foreign country, it is a shockingly violent one. It is easy to forget how dangerous life used to be, how deeply brutality was once woven into the very fabric of our lives.

The bulk of Pinker’s book is devoted to showing that the long-term trend for all forms of violence, including homicides, civil wars, and interstate wars, has been one of decline. There were some local peaks and valleys, but the violence curve starts very high and then gradually declines. It’s a “declining sawtooth.”

Pinker’s book triggered a lot of controversy, with both supporters and detractors dissecting the data on which his conclusions are based. Of particular interest to our goals in this book is the assessment of the Pinker thesis by academic anthropologists. One of the most thorough such critiques is War, Peace, and Human Nature, a collection of articles by a number of eminent archaeologists, anthropologists, and primatologists, edited by Douglas Fry.

In his summary of the evidence, Fry makes several excellent points. He agrees with Pinker that after the rise of large-scale states, or roughly over the last 5000 years, the overall trend in violence has been downwards. But Fry fervently disagrees with Pinker about the trajectory during the first 5000 years—after the adoption of agriculture, but before the rise of the states. He argues that violence, and especially warfare, actually increased, before it started to decline.

I agree. Multiple lines of evidence suggest that during the last 10,000 years the curve of war can be represented with the Greek letter Λ (lambda). Both the ascending and the descending trends are of course ‘jagged,’ because there were local increases and decreases superimposed on the long term Λ-trend. The peak position also varies among world regions, and generally coincides with late pre-state and early state societies.

However, Fry and others who contributed chapters to War, Peace, and Human Nature, go too far when they suggest that “war was simply absent over the vast majority of human existence” prior to 10,000 years ago.

Yes, during the climate chaos of the Pleistocene, warfare was probably rare. Human populations were in much greater danger of being wiped out by an advancing glacier than by another foraging band. When glaciers receded, enormous areas opened up for human colonization. Avoiding aggressors by moving away was both preferable and feasible. Yet there must have been periods of relatively stable climate when the local landscape would fill up. Nomadic foragers can be as territorial as farmers, and will defend rich hunting grounds or patches of valued plant resources. Once one group resorted to violence, war would spread: pacifist groups would be eliminated by natural selection. Such episodes of warfare could have been relatively rare during the Pleistocene, leaving no clear evidence in the archaeological record. If someone was killed by a well-thrown stone (or died later of the injury), how could we distinguish that from another unfortunate person who died in a hunting accident? In any case, we have very few skeletons from the Pleistocene, leaving us with scarce evidence for statistical analysis.

An additional problem underlying the prehistoric war controversy is that different people use different definitions of war. So let me be clear about what definition I use. My primary interest is in cultural group selection, and thus I define warfare as lethal group-on-group violence, no matter what forms it takes (battles, raids, ambush of stray individuals, etc.).

By this definition, both chimpanzees and wolves fight wars. Take Yellowstone National Park, where wolves were reintroduced in 1995, having been hunted to extinction earlier in the twentieth century. Once the wolf population increased to the point where all territory was divided up among the packs, between-pack violence flared up, ultimately becoming the chief cause of wolf mortality. We now have at least one example of a pack exterminating another one. It happened not in a single glorious battle, but by a thousand cuts, picking off one individual here, another there. The winning pack then expanded its territory and split into two.

When one pack of wolves exterminates another, I call it warfare, because it is between-group competition carried out by violent means. Other scholars use different definitions. Some insist that conflict should be “organized” to count. Others consider only large-scale conflict and exclude ‘primitive war.’ Such alternative definitions may be as valid as mine, being appropriate to the kinds of questions and conceptual approaches that other investigators use. But I am interested in warfare as a form of between-group competition.

We run into additional difficulties when trying to assess the prevalence of war in prehistory. Clearly we need to distinguish between interpersonal violence and group-level war. This can be difficult. A skull bashed in by a blunt object may indicate a death in battle or a murder resulting from a domestic dispute. For this reason, many anthropologists want to see additional indicators of group-level conflict before they can agree that it was warfare. Such archaeological signs could be fortifications or weapons specialized for man-on-man fighting (warclubs, swords). Bows and arrows, however, are equally useful in hunting and war. As a result, much warfare between small-scale societies, who tend to use ranged weapons and rely on raids and ambushes, will be invisible to archaeologists.

Let’s step back from this debate and consider how it affects the question we are currently investigating, the role of war in the rise of archaic states. While there is confusion resulting from alternative definitions, and a great degree of controversy about evidence and how to interpret it, all parties agree on one thing. Warfare was particularly vicious among pre-state farming societies. There is a lot of empirical support for what I called the Λ-shaped curve of warfare during the last 10,000 years. It is quite possible that the period after agriculture spread but before states arose was the most violent one in human history—at least when measured by the proportion of people who died as a result of war. If this is correct (and this is a very active research area, so we should expect more data soon, especially as the methods of forensic anthropology become better), it would strengthen the proposed link between war and the evolution of states. Watch this space.