The explanation for this surprising outcome is that New Guineans appreciated the benefits of the state-guaranteed peace that they had been unable to achieve for themselves without state government. For instance, in the 1960s I spent a month in a recently pacified area of the New Guinea Highlands, where 20,000 Highlanders who until a decade or so previously had been constantly making war against each other now lived along with one Australian patrol officer and a few New Guinea policemen. Yes, the patrol officer and the policemen had guns, and the New Guineans didn’t. But if the New Guineans had really wanted to resume fighting each other, it would have been trivially easy for them to kill the patrol officer and his policemen at night, or to ambush them by day. They didn’t even try to do so. That illustrates how they had come to appreciate the biggest advantage of state government: the bringing of peace.
Effects of European contact
Did traditional warfare increase, decrease, or remain unchanged upon European contact? This is not a straightforward question to decide, because if one believes that contact does affect the intensity of traditional warfare, then one will automatically distrust any account of it by an outside observer as having been influenced by the observer and not representing the pristine condition. Lawrence Keeley used the analogy of supposing that watermelons are white inside and become red only as soon as they are cut with a knife: how could one ever hope to demonstrate that watermelons really are red even before they are cut open in order to examine their color?
However, the mass of archaeological evidence and oral accounts of war before European contact discussed above makes it far-fetched to maintain that people were traditionally peaceful until those evil Europeans arrived and messed things up. There can be no doubt that European contacts or other forms of state government in the long run almost always end or reduce warfare, because all state governments don’t want wars disrupting the administration of their territory. Studies of ethnographically observed cases make clear that, in the short run, the initiation of European contact may either increase or decrease fighting, for reasons that include European-introduced weaponry, diseases, trade opportunities, and increases or decreases in the food supply.
A well-understood example of a short-term increase in fighting as a result of European contact is provided by New Zealand’s original Polynesian inhabitants, the Maori, who had settled in New Zealand by around AD 1200. Archaeological excavations of Maori forts attest to widespread Maori warfare long before European arrival. Accounts of the first European explorers from 1642 onwards, and of the first European settlers from the 1790s onwards, describe the Maori killing Europeans as well as each other. From about 1818 to 1835 two products introduced by Europeans triggered a transient surge in the deadliness of Maori warfare, in an episode known in New Zealand history as the Musket Wars. One factor was of course the introduction of muskets, with which Maori could kill each other far more efficiently than they had previously been able to do when armed just with clubs. The other factor may initially surprise you: potatoes, which we don’t normally imagine as a major promoter of war. But it turns out that the duration and size of Maori expeditions to attack other Maori groups had been limited by the amount of food that could be brought along to feed the warriors. The original Maori staple food was sweet potatoes. Potatoes introduced by Europeans (although originating in South America) are more productive in New Zealand than are sweet potatoes, yield bigger food surpluses, and permitted sending out bigger raiding expeditions for longer times than had been possible for traditional Maori depending upon sweet potatoes. After potatoes’ arrival, Maori canoe-borne expeditions to enslave or kill other Maori broke all previous Maori distance records by covering distances of as much as a thousand miles. At first only the few tribes living in areas with resident European traders could acquire muskets, which they used to destroy tribes without muskets. As muskets spread, the Musket Wars rose to a peak until all surviving tribes had muskets, whereupon there were no more musket-less tribes to offer defenseless targets, and the Musket Wars faded away.
In Fiji as well, the introduction of European muskets around 1808 made it possible for Fijians to kill each other in much larger numbers than they had traditionally been able to do with clubs, spears, and arrows. European guns, boats, and steel axes transiently facilitated inter-island head-hunting in the Solomon Islands in the 19th century: unlike stone axes, steel axes can behead many humans without losing their sharp edge. Similarly, European guns and horses, and European guns and slave-buyers, stimulated warfare in the North American Great Plains and in Central Africa, respectively. For each of these societies that I have just mentioned, warfare had been endemic long before European arrival, but effects of Europeans caused an exacerbation of warfare for a few decades (New Zealand, Fiji, Solomon Islands) or a few centuries (Great Plains, Central Africa) before it died out.
In other cases the arrival of Europeans or of other outsiders led instead to warfare’s end without any hint of an initial flare-up. In many parts of the New Guinea Highlands the first Europeans were government patrols that immediately ended warfare before European traders, missionaries, or even indirectly transmitted European trade goods could appear. When first studied by anthropologists in the 1950s, Africa’s !Kung bands were no longer raiding each other, although the frequency of individual murders within bands or between neighboring bands remained high until 1955. Four of the last five murders (in 1946, 1952, 1952, and 1955) resulted in the Tswana administration taking the killers off to jail, and that plus the availability of Tswana courts for settling disputes induced the !Kung to abandon murder as a means for resolving conflicts after 1955. However, !Kung oral histories report inter-band raids several generations earlier, until the time when increased Tswana contact introduced iron for arrowheads and other changes. Somehow, that contact resulted in an end to raiding long before the Tswana police intervened to arrest killers.
My remaining example comes from northwest Alaska, where formerly widespread fighting and exterminations among Yupik and Iñupiaq Inuit ended within a decade or a generation of European contact—not because of patrol officers, police, and courts forbidding war but because of other consequences of contact. The end of Yupik warfare is attributed to an 1838 smallpox epidemic that depleted the populations of several groups. The end of Iñupiaq warfare appears to have been due to the Iñupiaq chronic obsession with trade, and to their greatly increased new opportunities to trade furs to the Europeans with whom regular contact became intense after 1848: continued warfare would have been an obvious impediment to those opportunities.
Thus, the long-term effect of European, Tswana, or other outside contact with states or chiefdoms has almost always been to suppress tribal warfare. The short-term effect has variously been either an immediate suppression as well or else an initial flare-up and then suppression. It cannot be said that traditional warfare is an artifact of European contact.
Nevertheless, there has been a long history of denial of traditional warfare among Western scholars. Jean-Jacques Rousseau, already mentioned for his speculative theory of state formation not based on any empirical evidence, had an equally speculative and ungrounded theory of warfare: he claimed that humans were naturally compassionate in a state of nature, and that wars began only with the rise of states. Trained ethnographers studying traditional societies in the 20th century mostly found themselves dealing with tribes and bands that had already been pacified by colonial governments, until some anthropologists were able to witness the last examples of traditional wars in the 1950s and 1960s in the New Guinea Highlands and Amazonia. Archaeologists excavating fortifications associated with ancient wars have often overlooked, ignored, or explained them away, e.g., by dismissing defensive ditches and palisades surrounding a village as mere “enclosures” or “symbols of exclusion.” But the evidence of traditional warfare, whether based on direct observation or oral histories or archaeological evidence, is so overwhelming that one has to wonder: why is there still any debate about its importance?
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sp; One reason is the real difficulties, which we have discussed, in evaluating traditional warfare under pre-contact or early-contact conditions. Warriors quickly discern that visiting anthropologists disapprove of war, and the warriors tend not to take anthropologists along on raids or allow them to photograph battles undisturbed: the filming opportunities available to the Harvard Peabody Expedition among the Dani were unique. Another reason is that the short-term effects of European contact on tribal war can work in either direction and have to be evaluated case by case with an open mind. But the widespread denial of traditional warfare seems to go beyond those and other uncertainties in the evidence itself, and instead to involve reluctance to accept evidence for its existence or extent. Why?
There may be several reasons at work. Scholars tend to like, to identify with, or to sympathize with the traditional people among whom they live for several years. The scholars consider war bad, know that most readers of their monographs will also consider war bad, and don’t want “their” people to be viewed as bad. Another reason involves unfounded claims (to be discussed below) that human warfare has an inexorable genetic basis. That leads to the false assumption that war would be unstoppable, and hence to a reluctance to acknowledge the apparently depressing conclusion that war traditionally really has been widespread. Still another reason is that some state or colonial governments are eager to get indigenous people out of the way by conquering or dispossessing them or by turning a blind eye to their extermination. Branding them as warlike is used as an excuse to justify that mistreatment, so scholars seek to remove that excuse by trying to absolve the indigenous people of the charge of being warlike.
I sympathize with scholars outraged by the mistreatment of indigenous peoples. But denying the reality of traditional warfare because of political misuse of its reality is a bad strategy, for the same reason that denying any other reality for any other laudable political goal is a bad strategy. The reason not to mistreat indigenous people is not that they are falsely accused of being warlike, but that it’s unjust to mistreat them. The facts about traditional warfare, just like the facts about any other controversial phenomenon that can be observed and studied, are likely eventually to come out. When they do come out, if scholars have been denying traditional warfare’s reality for laudable political reasons, the discovery of the facts will undermine the laudable political goals. The rights of indigenous people should be asserted on moral grounds, not by making untrue claims susceptible to refutation.
Warlike animals, peaceful peoples
If one defines war as I defined it on p. 131—“recurrent violence between groups belonging to rival political units, and sanctioned by the units”—and if one takes a broadened view of “political units” and “sanctioned,” then war characterizes not only humans but also some animal species. The species most often mentioned in discussions of human war is the common chimpanzee, because it is one of our two closest living animal relatives. War among chimpanzees resembles human band and tribal warfare in consisting of either chance encounters or else apparently intentional raids involving adult males. Calculated war-related death rates in chimpanzees, 0.36% per year (i.e., 36 chimpanzees per year in a population of 10,000), are similar to those for traditional human societies. Does this mean that warfare was transmitted to humans in a straight line from our chimpanzee ancestors, hence that it has a genetic basis, hence that we are helplessly pre-programmed to make war, hence that it’s inevitable and can’t be prevented?
The answer to all four of these questions is no. Chimpanzees are not the ancestors of humans; instead, chimpanzees and humans are both descended from a common ancestor that lived about 6,000,000 years ago, and from which modern chimpanzees may be more divergent than are modern humans. It is not the case that all descendants of that common ancestor make war: bonobos (formerly known as pygmy chimpanzees), which genetically are the same distance from us as are chimpanzees and hence are the other one of our two closest animal relatives, are also derived from that common ancestor but have not been observed to make war; and some traditional human societies don’t make war. Among social animal species other than chimpanzees, some (e.g., lions, wolves, hyenas, and some ant species) are known to practise lethal fighting between groups, while others are not known to do so. Evidently, war does arise repeatedly and independently but is not inevitable among social animals in general, nor within the human-chimpanzee evolutionary line in particular, nor among modern human societies more particularly. Richard Wrangham argues that two features distinguish those social species that do practise war from those that don’t: intense resource competition, and occurrence in groups of variable size such that large groups sometimes encounter small groups or individual animals which they can safely attack and overwhelm by numbers with little risk to the aggressors.
As for a genetic basis to human warfare, it of course has a genetic basis, in the same broad and distant sense in which cooperation and other multi-faceted human behaviors have a genetic basis. That is, the human brain and hormones and instincts are laid down ultimately by genes, such as the genes that control the synthesis of the hormone testosterone associated with aggressive behavior. However, the normal range of aggressive behavior, like the normal range of body height, is influenced by many different genes and by environmental and social factors (like effects of childhood nutrition on adult height). That’s unlike single-gene traits such as sickle-cell hemoglobin, which a person carrying the gene for that trait synthesizes regardless of childhood nutrition, other genes, or environmental competition. Like warfare, warfare’s converse of cooperation is widespread but variably expressed among human societies. We already saw in Chapter 1 that cooperation between neighboring human societies is favored by certain environmental conditions, such as resource fluctuations within or between years, and whether or not a territory contains all resources necessary for self-sufficient survival. It is not inevitable or genetically programmed that neighboring small-scale societies cooperate; there are reasons why some cooperate more and some cooperate less.
Similarly, there are external reasons why some human societies are peaceful, although most are not. Most modern state societies have been involved in recent wars, but a few haven’t, for understandable reasons. The Central American nation of Costa Rica hasn’t had a recent war, and even abolished its army in 1949, because its historical population and social conditions resulted in relatively egalitarian and democratic traditions, and its only neighbors (Nicaragua and Panama) are unthreatening and offer no targets of great value to conquer except the Panama Canal, which would be defended by the U.S. Army if Costa Rica were foolish enough to invest in an army to attack the canal. Sweden and Switzerland haven’t had recent wars (although Sweden formerly did), because they now do have aggressive and far more powerful and populous neighbors (Germany, France, and Russia) which they could never hope to conquer themselves, and because they have successfully deterred those neighbors from attacking them by being armed to the teeth.
Like these modern states without recent involvement in wars, a small minority of traditional societies have also been peaceful for understandable reasons. Greenland’s Polar Eskimos were so isolated that they had no neighbors, no outside contacts, and no possibility of war even if they had wanted it. Absence of war has been reported for quite a few small bands of nomadic hunter-gatherers living at very low population densities, in harsh unproductive environments, with large home ranges, with few or no possessions worth defending or acquiring, and relatively isolated from other such bands. These include the Shoshone Indians of the U.S. Great Basin, Bolivia’s Siriono Indians, some Australian desert tribes, and the Nganasan of northern Siberia. Farmers without a history of war include Peru’s Machiguenga Indians, living in a marginal forest environment not coveted by others, without pockets of good land sufficiently dense or dependable to warrant war or defense, and with currently low population density, possibly because of a recent population crash during the rubber boom.
Thus, it could not be claimed tha
t some societies are inherently or genetically peaceful, while others are inherently warlike. Instead, it appears that societies do or don’t resort to war, depending on whether it might be profitable for them to initiate war and/or necessary for them to defend themselves against wars initiated by others. Most societies have indeed participated in wars, but a few have not, for good reasons. While those societies that have not are sometimes claimed to be inherently gentle (e.g., the Semang, !Kung, and African Pygmies), those gentle people do have intra-group violence (“murder”); they merely have reasons for lacking organized inter-group violence that would fit a definition of war. When the normally gentle Semang were enlisted by the British army in the 1950s to scout and kill Communist rebels in Malaya, the Semang killed enthusiastically. It is equally fruitless to debate whether humans are intrinsically violent or else intrinsically cooperative. All human societies practise both violence and cooperation; which trait appears to predominate depends on the circumstances.
Motives for traditional war
Why do traditional societies go to war? We can try to answer this question in different ways. The most straightforward method is not to attempt to interpret people’s claimed or underlying motives, but simply to observe what sorts of benefits victorious societies gain from war. A second method is to ask people about their motives (“proximate causes of war”). The remaining method is to try to figure out their real underlying motives (“ultimate causes of war”).