Are humans “natural born killers”? If you believe that, they’ve got a war they want to sell you (AWTWNS 29 September 2014)

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Are humans “natural born killers”? If you believe that, they’ve got a war they want to sell you

29 September 2014. A World to Win News Service. You probably saw the headlines: “Chimps and humans are both ‘natural born killers’ with an almost psychopathic tendency towards violence and slaughter” (The Independent, 17 September). “Natural born killers: chimpanzees are inherently violent and wage war like their human ‘cousins’, study claims” (Daily Mail, 17 September). “Chimpanzees and humans have one trait in common – both are natural born killers, scientists have shown” (USA Today).

These newspaper articles were prompted by the publication of a meta-study (a survey of previous research) in the prestigious scientific journal Nature entitled “Lethal aggression in Pan is better explained by adaptive strategies than human impacts” written by 30 scientists who analysed the reports of all known killings by chimpanzees, 158 killings in 18 chimpanzee communities over 50 years in east, west and central Africa.

The meta-study, called Wilson et al. (and others) after its lead author, limits itself to chimpanzee behaviour and presents no evidence whatsoever about human behaviour. Nevertheless, several of its authors and the media stepped out of the framework of the facts it examines to weigh in on another question, the claim that chimpanzees can be “a model for understanding human violence,” as Michael Wilson explained in a post-publication interview. Its senior author, Richard Wrangham, once wrote that Chimpanzee-like violence preceded and paved the way for human war”.

This is a very important and hotly debated topic among scientists in many fields and society in general. Proponents of the idea that a tendency towards aggression and even war is genetically rooted in human beings often argue that it is an adaptation, a trait that gives organisms an advantage in a given environment, that our distant primate ancestors passed along to us. They look for evidence in the behaviour of other modern primates such as gorillas and baboons, and lately our genetically closest cousins, chimpanzees, whose genetic structure is closer to ours than it is to other apes.

But the actual subject of Wilson et al., the facts it examined by reviewing fieldwork reports, was not whether or not human or even chimpanzee social behaviour could be explained by genetics, but under what circumstances chimpanzees kill each other. It was designed to answer the question of whether violence between groups of chimpanzees is occasioned by human impact on their environment, so that they act in a way that they would not have in the absence of human intervention, in what could loosely be called their natural state, as some researchers have concluded.

For instance, the pioneering primatologist Jane Goodall suggested that her own activities in providing bananas to encourage the chimpanzees she studied to stay put caused an unusual concentration of male chimps and provoked previously unseen kinds of behaviour. This human impact idea has been one line of reasoning against claims of genetically determined behaviour in other primates, let alone people.

Wilson et al. concluded that chimpanzees kill within their own communities and more often chimpanzees of other communities regardless of human presence. The paper does not actually address the question of why. Its summary carefully states that “our results are compatible with previously proposed adaptive explanations for killing by chimpanzees, whereas the human impact hypothesis is not supported.” While it provides evidence in the debate about genetics and behaviour, it does not prove that chimpanzees are genetically disposed toward violence, but merely that they sometimes are violent.

Chimpanzee behaviour is not invariable. It can change dramatically in different circumstances. They are capable of learning and teaching each other, with some incipient degree of culture. Not everything they do is necessarily programmed in their genes, although their genetics set the stage for what is possible. There can be social as well as genetic “adaptive explanations”, which are two very different things.

Further, what exactly is shown by the statistics about violent incidents they survey? In his blog on Scientific American, John Horgan argues that if one excludes the killings of infant chimps within a particular group, individual acts that have little analogy in human society, the number of directly observed or inferred killings (bodies found with bite marks, etc.) is low. There are well-known instances in which chimps in one group have killed chimps of another, usually in collective raids since it takes several adult chimps to kill another one. But this behaviour that is often cited as a precursor of human war is relatively rare. Using the cases listed in the Nature paper, Horgan calculates an average of one every fifteen years per community. But even Horgan fails to mention how greatly this violence seems to vary from one community to another and at different times, an important fact because it suggests the complex relationship between the biological makeup of individual chimps and their physical and social environment.

Horgan also makes an even more powerful argument against the idea that this study means much about human behaviour: Among bonobos (Pan paniscus, also called pygmy chimpanzees), a species that is less common than the Pan trogodytes (commonly just called chimpanzees) on the other side of the Congo River that the study focuses on, any kind of violence is rare and inter-communal killings all but unknown. (Wilson et aal. examined four bonobo communities and found only one “suspected” killing.) In fact, bonobo behaviour and their social structures are very different than chimps in many ways. For instance, unlike chimps, males are not dominant among bonobos. Since bonobos are as genetically close to modern human beings as chimpanzees, this is a strong counter-argument to the claim that the common ancestors of people and chimps passed on genes for violent behaviour.

What best describes and accounts for the spectacular success of our species is the degree to which human behaviour is not biologically programmed – human beings’ ability to change as they change their world. As Karl Marx wrote, “All history is nothing but the continuous transformation of human nature.” In a book advancing this understanding, Ardea Skybreak wrote, “Luckily for those of us who don’t particularly like the present order of things, all of history points to the prevailing social relations rather than innate constraints in our biological makeup as the key factor mediating every aspect of human social life at different points in history and in different parts of the globe.”

There is evidence, including recent archaeological findings, that while there was violence within and especially between communities, war was unknown among modern human beings for more than 100,000 years. Roughly 13,00 years ago, the development of agriculture, raising animals and other developments in the way people produced what they needed to live and made it possible for the emergence of private property and the division of society of into classes. Ever since that time, the dominate ideas in societies have been those corresponding to the interests and outlook of the ruling classes.

As Skybreak says, “How ironic and revealing, then, that just as we finally attain a level where a material basis exists for doing away with oppression and exploitation on a global scale, there are long lines of apologists in the sciences and the media who are bending over backwards to find some kind – any kind – of proof for the notion that there are some unchanging innate characteristics of human nature which would make this leap impossible.”

The unjustified conclusions drawn from the Nature paper are an example of “confirmation bias”, a kind of circular reasoning where, consciously or unconsciously, people choose to honour some alleged evidence and discard other evidence and arguments because they consider truth to be determined by whatever they have already concluded – or by the prevailing ideas in society, in this case that violence and even war are embedded in human beings’ genetic make-up.

The outstanding multi-disciplinary scientist Stephen Jay Gould once described such conclusions about “human nature” as “unsupported speculations with political clout.” There is no scientific evidence for the existence of the kind of unchanging and unchangeable “essence” that is meant by the term “human nature”.

As the blogger Horgan reminds readers, this conception of inherently violent “human nature” is popular not only among scientists accorded high status, such as Edward O. Wilson and Stephen Pinker, it is also favoured by U.S. political leaders from the Bush administration to Obama. “Barack Obama was alluding to the theory when he said in 2009, while accepting the Nobel Peace Prize, ‘War, in one form or another, appeared with the first man,” Horgan writes. In other words, even as he was accepting the peace prize, he was arguing that war is an inevitable and eternal consequence of human biology.

This idea is implicit in today’s speeches of U.S., UK and French leaders about the situation in Syria and Iraq, which they ascribe to “barbarism” and “savages”, as if people who reject the cruel and hypocritical “Western civilization” they represent were reverting to humanity’s default state. Some reactionary commentators argue that this makes it wrong to look at the economic, social and political factors that gave rise to the also reactionary Islamist jihadis, such as the effects of their own wars of aggression and occupation and the global imperialist system that has thrived on the domination of whole nations by the monopoly capitalists based in a handful of powers.

To his credit, the paper author Wrangham told The New York Times, “I certainly wouldn’t want to say that chimps have anything much to say directly about what’s going on in Syria.” (17 September 2014). But by arguing that chimpanzee behaviour indicates that human beings are programmed for war, as he repeats in this interview, that is the claim he is giving aid and comfort to with his own faulty conclusions.

Complex human behaviour is not genetically programmed, and still less social behaviour, such as war, on any scale. As has been seen once again in the West over the past few months, a “war mood” is made, not born. It is created when the political representatives of the ruling classes feel the need to go to war – it is the result and not the cause of political decisions.


This article is indebted to John Horgan’s Scientific American blog, particularly the posts of 17 and 18 September 2014, and 29 June 2010. He discusses recent literature on the emergence of war about 13,000 years ago, after hundreds of thousands of years of the existence of modern humans, in his posts of 23 July and 2 August 2013.

Bob Avakian discusses the question of human nature in pp. 226-234 of his book Away with All Gods (Insight Press, 2008), and examines it in relation to early human societies and the rest of human history in “Views on Socialism and Communism, A Radically New Kind of State,
A Radically Different and Far Greater Vision of Freedom”, particularly the section “There Is No Such Thing As Human Nature” (Revolution, 08 March 2006,

Ardea Skybreak’s Of Primal Steps & Future Leaps (Banner Press, 1984) is a profound and path-breaking examination of the relationship between evolution and human society. See particularly pp 78-80.

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