War Has Deep Roots in Human Nature, But It’s Not Inevitable

By Razib Khan | July 5, 2012 1:35 pm

Thomas Malthus

In the June 2012 issue of Discover, E. O. Wilson authored a piece with the provocative title, “Is War Inevitable?” Derived from his recent book The Social Conquest of Earth, the narrative has a rather simple answer to the question implied in the title: war is inevitable, because it is part of human nature, and, perhaps more provocatively, it shaped human nature. John Horgan, who recently penned The End of War, rebuts Wilson’s argument in a point-by-point fashion in a companion article, “No, War Is Not Inevitable.” I find myself in a curious position: I agree with John Horgan in terms of the conclusion—that war is not inevitable—but not for the same reasons. While Horgan is right that Wilson relies on a particular, controversial group of ethologists to make the assertion that chimps have frequent inter-group conflicts and humans have always had wars, so Horgan leans upon his own preferred group of scholars to make the opposite points. But both of them, I think, miss the crucial part of the answer: the tricky interplay between nature and nurture.

With a strong background in ecology, Wilson assumes a Malthusian paradigm when it comes to human numbers and human resources. In other words, we are subject to a carrying capacity. When there is a surplus of resources population size increase, and “catches up” to the resource base. After a time an equilibrium develops between population and resources. How? The reality is that for solid evolutionary reasons, individuals do not reduce their own reproductive output altruistically. Rather, the population “self-regulates.” In the jargon there is “intra-species competition,” as individuals and groups scramble for finite resources. (There are also, of course, inter-species factors, like predator, prey, and parasites.) The losers die, while the winners reproduce. Each generation is witness to conflicts which check the population and maintain the equilibrium.

Most people know that in a human context such ideas are attributed to Thomas Malthus, but in a biological sense this model is widely held as the default nature of things: Natural populations engage in self-regulation through conflict and resource exhaustion. Anyone with a robust biological background would expect that inter-group conflict would emerge as the result of the iron laws of reproduction and finite resources. In that light, Wilson’s Manthusian assumption seems justified.

But today we know Thomas Malthus was wrong. How so? You might be tempted to argue that innovation generated such economic productivity that we escaped the Malthusian trap. This is the smaller part of the answer. Malthus himself lived in an England where productivity and wealth was increasing, but poverty continued due to increased population growth. After all, what happens when productivity and wealth increase? People have more children, who then divide the larger pie by larger numbers. This is the pattern of our species. But actually you know that this is not what happened! The demographic transition occurred, which Malthus, and every other individual alive before 1850, could not have anticipated. The population did not grow proportionate to economic productivity. Rather, family size shrank, while economic productivity continued to increase! And voila, the Malthusian nightmare is averted due to an unexpected sociological phenomenon.

What does this have to do with war? Wilson is correct that war has been ubiquitous across recorded history, and I agree with his argument that inter-group conflict has deep evolutionary roots in our species. But there are two issues here. First, just because something has deep evolutionary roots does not necessarily mean that it is genetically encoded. Rather, the personality traits and dispositions are inherited, and these are the basic raw materials that lead to warlike tendencies. Second, these traits and dispositions can be easily, almost inevitably, evoked given the proper environmental context. This last clause is critical: alter the environmental context, and you may alter the expression of a given phenomenon.

Pestilence, war, and famine are as old as human history. Slavery has been ubiquitous across human societies. And yet today in the developed world we have escaped many of these inevitable and eternal ills. How? Through changed environmental conditions. E. O. Wilson knows general ecological theory, but he, like many biologists, neglects applied human ecology: economics. Is it any coincidence that the quixotic quest to abolish slavery took fire in Western Europe late in the 18th century, just as those societies were on the precipice of massive economic growth and social change?

John Horgan argues that war is a “cultural innovation, an especially vicious, persistent meme, which culture can help us transcend.” In the broadest sense, there is truth to this, but I think it is more accurate to characterize war as a cultural phenomenon that bubbles up from the genuine innate depth of human nature, given particular environmental conditions. It is not an innovation of human ingenuity, it is an evocation of human instinct.

But to say that war is inevitable is to say that poverty is inevitable. Perhaps in the long run, the socioeconomic context will change back, and humans will once again fall prey to Malthusian population limits and our innate war-like tendencies. But at least in our present age, these curses of the past have been broken, and it is not vain to struggle so that we will be free from them for many generations longer.

CATEGORIZED UNDER: Mind & Brain, Top Posts
  • http://blogs.scientificamerican.com/cross-check/ John Horgan

    Razib, typically smart, subtle post. Thanks. A few points. First, if you cherry pick data you can make a case for Malthusian theories of war, but overall the evidence undercuts that view. Napoleon Chagnon, whose work is invariably cited by Wilson, Pinker, Wrangham and other war-is-in-our-genes theorists, found an INVERSE correlation between population density and game scarcity and warfare among the Yanomamo. Lawrence Keeley also discounts population density and scarcity in his influential book War Before Civilization (also a favorite of Wrangham et al), and Lewis Fry Richardson discounts Malthusian and Marxist factors (economic inequality rather than scarcity per se) in his study of modern conflicts, The Statistics of Deadly Quarrels. I wish you’d read my book The End of War, because if you did I think you’d see that the evidence strongly supports a view of war as a tradition, invention, custom that can start for many reasons but then becomes its own primary cause.

  • Helga Vierich

    For most of our evolutionary history, humans were foragers. Among mobile foragers on a diet of wild plants and animals, the mechanisms of birth spacing*, of infant mortality, of accidental death, of periodic diseases and natural accidents and predation would have balanced the population without any thought being required. And this would have been the case during 99 % of human evolution.

    The only time thought was required was when too many kids started being born too closely spaced, and enough of them survived to accelerate the doubling time to the point where local game and wild plant foods became scarce. This might have happened, once in a while, to sedentary foraging peoples based on fixed resources like annual Salmon runs or huge stands of wild grain, but it would hardly have been typical of most mobile forager groups.

    However, when, throughout a culture area, reciprocal access to resources was no longer a viable strategy for long-term survival, THEN the whole game has to change to the nastier one where you simply went over to your neighbors and took their food away, if they had any, and killed them all, so that next year they would not do the same to you. An awful but effective survival strategy, increasingly common during the Mesolithic period just before food production systems got underway. The domestication of plants and animals, seen in this light, is yet a further adaptation to resource scarcity and local wild food depletion.

    The apparent disconnect between observed high population density and local warfare intensity is not so strange. It is predictable. What local warfare does is it curbs population growth. Among subsistence level food producers, warrior cults tend to raise the status of males and lower that of females. this results in higher morbidity and mortality among females, through polygny, abuse, dietary restrictions, female infanticide and neglect of female children. This produces a perceived shortage of women, establishing a feedback loop stimulating further raiding and hostilities. Villages with frequent hostilities tend to establish wider buffer zones (no-man’s land). This preserves habitats for wildlife and wild food plants, so people stay healthier. Therefore, the highest frequencies of inter village warfare would be the zones of lowest population densities and higher nutritional status, which is exactly what Napoleon Chagnon’s data on the Yanomami confirmed.

    The fact that warfare has been pretty standard practice ever since for the small fraction of humanity who got stuck in this demographic trap, however, does not justify turning it into an force driving human evolution. War is within the human range of possible responses to high population:, but also that it is a behavior algorithm that requires a trigger. That trigger, it appears, was usually an in initial upward shift in population: resource ratios over a large culture area, a shift that precluded options based on reciprocal access (redistributive feasting, trade, and migration) and made raiding and warfare into an adaptive strategy for long term control to keep that ratio from getting much higher.

    Just because the resort to inter-group violence is within the range of human behavior does not, however, make it a likely part of our evolutionary environment of adaptation. The scientific evidence, both archaeological and ethnographic, does not support such a conclusion. The Mesolithic was only, at most, 12-15,000 years ago, and it did not begin then for all humanity, but only for a TINY proportion of the world’s human population. Most humans were still foragers until well into the last three thousand year period, indeed, in Australian, much of North America and Sub-equatorial Africa, they were most foragers until 150 years ago.

    A demographic trap led to war, starvation, rich and poor, domestication of animals and plants, and eventually, civilization.” The process of settling into more permanent villages around food storage facilities holding millions of calories (of cereals, dried vegetation, meat and fish) led to a demographic trap that no one could have foreseen, and resulted in a population explosion leading to just the sort of scenario that Keeley’s book documented. However, Keeley’s material was from predominantly sedentary groups, and most of them were not even foragers. The Yanomamo are slash and burn horticulturalists, for instance.

    But no, we are not the dazed survivors of millions of years of little territorial groups who survived because we frequently went out and beat the shit our of each other and stole each other’s lands and females. Please. We evolved to be smarter and considerably more nuanced in our inter-group behavior than such a chimp-based model would suggest.

    I think we evolved to be strategic thinkers, not only in the Machevellian sense, but also in the Humanist sense – we tend consider the long term benefits of alliances and trading partnerships (both in terms of expanding our own groups options in times of scarcity and also in terms of expanding our access to a wider gene pool).

    Finessing inter-cultural relations that permitted trading networks to span entire continents took subtlety and self-control far superior to that involved in resorting to violence every time someone had resources you wanted or needed. There is a reason we humans evolved a brain that can easily handle not just one but many languages, and not just one but many cultural inter-faces.

    The “man as nasty beast” model that is currently in vogue is hardly new. It has been popularsince the days of Plato and Aristotle. That does not mean it is based on science. It is quite likely based on the wishful thinking. How nice it would be if some kind of state control system is needed to control human badness and is, therefore, not only justifiable but beneficial. I am sorry that so many, otherwise sensible, scholars, from Lawrence Keeley and Stephen Pinker to E.O. Wilson and Richard Wrangham have fallen for it.

    Newsflash: Man is not a nasty beast. He is smart and funny and, given half a chance, would rather talk things over than get into a fight that might hurt him or sour relationships with potential trading partners and allies – or even potential mates and in-laws. Give humanity credit for having evolved to be a bit smarter than other chimps.

    Our finest survival mechanism, culture, might also be our nemesis, however. What has been blunderingly “successful” around the world in the last 12,000 years have been eco-busting, bullying, megalomaniacal cultural systems, highly stratified, stressful, and warlike. They have lately driven the foraging way of life to the brink of extinction, and may yet capture control even over the remaining subsistence-level food producing systems. These seem to me like supernova cultures, and they may be humanities undoing. What is worse, alas, is that, more than any other previous cultural systems, these are capable systematically making far too many people immune to rational thought and long term planning.

    *Among many mobile hunter-gatherers, the birth spacing is much longer than among farming or pastoral people because of breast-feeding that continued well into the third year of a child’s life. Regular stimulation of the mother’s nipples, by suckling, causes a cascade of hormonal responses that tends to prevent ovulation – as long as breast-feeding frequency is sustained (every 2-3 hours). As long as the infant sleeps with its mother, breastfeeding can continue throughout the night without much disturbing the sleep of the parent. Among hunter-gatherers, where high calorie weaning foods such as cereals and animal milk or not available, this continuing lactation gives the child’s gut time to grow large enough to handle enough fruit, vegetables and meat to complete the weaning process during the fourth year of life.

    It is wrong from the start to ASSUME a rate of population growth, similar to that of a modern farming community.

    I would suggest that there was an fairly rapid shortening of the birth-spacing interval – from an average of 48 months to about 24 months- with the onset of sedentary villages around stores of food cached for long periods (like dried fish, cereal grains, potatoes etc. Generally these stored foods provided high-calorie weaning foods of a kind that mobile hunter-gatherers did not have on hand very often. So then, since their infants did not continue to suckle as frequently, mothers got pregnant sooner than they would have under the old forager system.

  • http://blog.locustfork.net/ GW

    Or to put it another way.

    Will Humans Ever Achieve World Peace?

  • http://backseatdriving.blogspot.com/ Brian Schmidt

    “Slavery has been ubiquitous across human societies.”

    Not hunter-gatherer societies, where it was very rare, and they constitute the vast majority of human history. The lesson I draw is that widespread behavior can appear from nowhere and then disappear regardless of the innate human condition, for the reason Razib gave of changed environmental conditions.

    Re comments about Keeley – I don’t recall what he said about population density, but he certainly believed that extremely few pre-civilized cultures were peaceful, and that wars were easy to provoke and continue (any hothead could launch an arrow and get one going) and difficult to end.

    I think it’s something of a weakness in Keeley in that he grouped ‘pre-civilized’ agrarian with hunter-gatherer groups. To the extent that our psychology is genetically determined, I assume we’re optimized primarily for being successful hunter-gatherers and only secondarily to live as farmers (and barely at all as townspeople). Looking at innate human condition would mean hunter-gatherers, but I guess there’s much less data.

  • https://plus.google.com/109962494182694679780/posts Razib Khan

    I wish you’d read my book The End of War, because if you did I think you’d see that the evidence strongly supports a view of war as a tradition, invention, custom that can start for many reasons but then becomes its own primary cause.

    fair enough. i’ll put that in my “stack” and see what you come up with.

    Man is not a nasty beast.

    i think this is as true as the assertion that man is a nasty beast. give me such a reductive maxim, and i’ll call it an illusion. re: the birth-spacing argument. i’ve heard it before. if so, than man seems to be a somewhat sui generis beast, when it comes to group living organisms and intra-specific competition. not impossible, but my prior remains skeptical. but i’ll look at the lit. horgan talks about at some point and make a ‘final decision’ :-)

  • https://plus.google.com/109962494182694679780/posts Razib Khan

    The lesson I draw is that widespread behavior can appear from nowhere and then disappear regardless of the innate human condition, for the reason Razib gave of changed environmental conditions.

    this is a compelling observation.

  • Frank Rush

    If you are interested in an evidence based analysis of human violence, I can recommend:

    The Better Angels of Our Nature: Why Violence Has Declined by Steven Pinker:

    We’ve all asked, “What is the world coming to?” But we seldom ask, “How bad was the world in the past?” In this startling new book, the bestselling cognitive scientist Steven Pinker shows that the world of the past was much worse. In fact, we may be living in the most peaceable era yet. Evidence of a bloody history has always been around us: the genocides in the Old Testament and crucifixions in the New; the gory mutilations in Shakespeare and Grimm; the British monarchs who beheaded their relatives and the American founders who dueled with their rivals. Now the decline in these brutal practices can be quantified. Tribal warfare was nine times as deadly as war and genocide in the 20th century. The murder rate in medieval Europe was more than thirty times what it is today. Slavery, sadistic punishments, and frivolous executions were unexceptionable features of life for millennia, then were suddenly abolished. Wars between developed countries have vanished, and even in the developing world, wars kill a fraction of the numbers they did a few decades ago. Rape, hate crimes, deadly riots, child abuse — all substantially down. How could this have happened, if human nature has not changed? Pinker argues that the key to explaining the decline of violence is to understand the inner demons that incline us toward violence and the better angels that steer us away. Thanks to the spread of government, literacy, trade, and cosmopolitanism, we increasingly control our impulses, empathize with others, debunk toxic ideologies, and deploy our powers of reason to reduce the temptations of violence. Pinker will force you to rethink your deepest beliefs about progress, modernity, and human nature. This gripping book is sure to be among the most debated of the century so far.

  • https://plus.google.com/109962494182694679780/posts Razib Khan

    #7, i’ve read the book. and steven is a moderate acquaintance of mine (e.g., he cited one of my blog posts in defense of the book actually).

  • Helga Vierich

    If you were to do a frequency graph of WARFARE it would show a bell curve starting from a low level at the beginning of the early Mesolithic (generously, say, 15,000 BP) and rising to a peak in the twentieth century. If you use % of persons killed in war/maimed in war as a function of total population, the peak would be even steeper.

    If you do a similar graph of the frequency of murder and lesser interpersonal violence, the graph would not be q the same, since even among mobile foragers who have strong social controls over interpersonal aggression, murders do happen, fight do happen. Since states and empires tend to take corporal punishment and the enforcement of social controls upon themselves, it is not surprising that ordinary citizens of states, especially powerful prosperous states, have been relatively safe from violence, and that is one of the things that has been a particular gain made in the high energy/high prosperity period marked by the industrial period, and particularly by the age of oil. But it applies especially to a particular segment of the population, the expanding middle class.

    Pinker does not really distinguish between internal criminal violence, domestic violence, and murder vs warfare as a cause of death in the data he draws on from Keeley. Keeley could not do it, because of the nature of much of the data made it ambiguous. Was a person from a mesolithic burial marked by signs of brutal violence because of warfare or was he a murder victim?

    Humans have always had the capacity for lethal violence. I am not by any means suggesting that our forager ancestors were a bunch of peace-nic pacifists. The foragers I lived with in the Kalahari had tempers and got into arguments and even fights. There was even a murder done among them forty years before I arrived in the field, which people still discussed in vivid detail (it apparently involved the termination of dangerous psychopath by his own kinsmen).

    But the threat of anger and of more extreme and possibly violent action served a purpose – it was the point that no one wanted matters to reach. Fighting was considered to represent a failure of rational people speaking in good faith, which was a very shameful thing. All kinds of good future options for gifting, reciprocal access to territory, and potential marriage negotiations, were “thrown away” by displays of temper, so therefore displays of temper were considered very foolish and childish and cruelly mocked.

    I agree with Razib. I should not have stated it so baldly as to leave it open to the logical counter thrust. Perhaps I ought to have said simply that Man is a thinking beast, and both “nasty” and “nice” are minted within the realm of cultural strategy, not human nature alone.

  • http://backseatdriving.blogspot.com/ Brian Schmidt

    The birth spacing argument has to involve very wide spacing, high infant mortality, and/or short female lifetimes to keep populations from expanding to Malthusian limits. If the wide spacing is a cultural artifact, then it has to be a universal cultural artifact: any hunter-gatherer culture that skipped it would expand its population and start encroaching on others.

    I have a lot of trouble buying the idea that humans whose limited technologies were in stasis for thousands of years at a time weren’t subject to demographic expansion like every other animal.

    The other argument made by people who think that warfare is a modern/historical invention is that they acknowledge interpersonal violence as universal but make a categorical distinction with warfare. The categorical distinction might be meaningful in “civilized” cultures but I think it has little meaning outside of elaborate, civilized social structures.

  • The Bobs

    Technology has increased the carrying capacity by a large margin. This happened quickly, so the population lagged behind. As long as the population continues to increase, the carrying capacity will eventually be reached. We may already have exceed the long term carrying capacity of the Earth.

  • http://www.junjaytan.com Junjay

    I haven’t read John Horgan’s book so I can’t speak to what’s discussed there, but I do find myself siding more with E.O. Wilson’s viewpoint. If we imagine a world that lacks resource conflicts and has a lot to lose economically from war, there are still other reasons to go to war such as pride and ideology. The allure of holy wars and the spread of the cold war comes to mind. Further, look at the popularity of sports in the world. You could view this as a microcosm of society’s need for competition, of pitting us against them. Anecdotally it seems to me that the need for conflict is hard wired into humanity, despite my wanting to hope otherwise.

  • Helga Vierich

    @Brian Schmidt
    Regarding your statement that wide birth spacing is “a cultural artifact” I wonder if you would also say this of the birth spacing seen in Red Deer or whales or elephants? Within our original foraging adaptation, the timing of weaning and the subsequent spacing of births was to a large extend controlled by physiological rather than cultural factors, as the toddler’s gut had to grow to sufficient size to accommodate enough of the rather coarse vegetable.nut.root/meat diet to support its continued growth in the absence of high calorie weaning foods.

    I also find it is bit questionable to simply assume that “every other animal” was subject to “demographic expansion”. Species have, generally, the rate of reproduction that permits them to increase to the limit of their food supply, but other vectors tend to keep their numbers below this point. In humans the main predators since the late Pleistocene have always been microbial and parasitic infections. These account for most of the mortality in the younger age groups, as well as in the extremely old. These are very effective in almost every known species. Other factors, like occasional droughts etc, and even extreme changes in climate due to volcanic eruptions and ice ages, also played a role in cutting back on human numbers time and again.

    I would hesitate to assume that very much about humans is “hard-wired” except the drive to learn and accommodate oneself to ones culture of birth, and.or, to the culture in which one finds oneself dependent at any point in one’s later life. The sex and the “in-love” drive, the drive to eat and drink, are a given, of course.

  • Helga Vierich

    @ Razib Khan:
    Razib, have you ever read Catton’s book Overshoot? http://books.google.ca/books/about/Overshoot.html?id=_e-Q56mT6k4C See also Albert Bartlett’s lecture http://www.youtube.com/watch?v=cOrvGDRLT7A&feature=related

    Catton did an interesting essay reflecting of Malthus. http://desip.igc.org/malthus/Catton.html
    I’m sure you must have seen Joe Tainter’s book, yes?

  • Helga Vierich

    No, will humans ever achieve World Peace Again?

  • rusty

    Sorry, I could not disagree more.
    Do we all agree that climate does change? History tells us it does.
    Give the world 10 years of failed crops, leading to a world wide foot shortage.

    I promise you, this will result in a war.
    Is it inevitable? 100% guaranteed. War is inevitable.

  • rusty

    It’s deeper than cultural strategy though. It’s part of our genes. Have you not heard of the warrior gene?
    It doesn’t guarantee that I will be aggressive, but it guarantees someone will be. The real question is percentages. No matter how much we punish, boy, coax, nurture, educate, you will always trigger aggression at some point.
    Competition for resources (as was suspected at crow creek in the 1300s) is a simple example. Crops fail, people compete for food. It’s a 100% ironclad guarantee for violence.

  • rusty

    Weather has never been so stable and moderate. Change the weather and the pendulum will swing back to more violence (eg. Bad weather = spoiled crops = competition/conflict).


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About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com


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