by Mark Pagel
Chauvinism? Some will say yes, and the Neanderthals have their apologists. But at a time when modern humans were overflowing with sophisticated artifacts, there is no evidence that Neanderthals could engrave or shape bones, they had no sewing, no weaving, no bows and arrows, and no spear throwers, even though they would have been able to observe all of these things among the talented newcomers who had moved in right alongside them. Some Neanderthal archaeological sites yield shaped pieces of shells that might have been used as jewelry, and other sites suggest that they added symbolic objects such as flowers to graves. (Burial itself should not be taken as any sort of religious, spiritual, or symbolic act. Dead bodies decay rapidly and attract flies and predators, so burial is simply a prudent thing to do.) But even these practices seem only to appear when Neanderthals had prolonged exposure to modern humans, and very recent evidence suggesting that Neanderthals actually produced and wore pieces of jewelry is now being reinterpreted as the work of Homo sapiens. The paleontologist Chris Stringer has even speculated on a BBC radio program that if there were slight changes in some Neanderthals’ capabilities late in their history, this might reflect brain genes they had acquired from their interbreeding with modern humans.
This description of the Neanderthals is not what we expect of a species with true social learning. No one can be sure, but we can only guess that the mental life of the Neanderthals was, and still is for all other animals, a plodding, inflexible, literal, and unimaginative existence, at least compared to ours. While we were spreading around the world, the Neanderthals’ limited technologies meant they were confined almost exclusively to the environments of Western Europe, parts of the Middle East, and southern Siberia. While we were using sophisticated spears and arrows to hunt large mammals, the Neanderthals were close-range hunters with short spears for jabbing, or who relied on clubbing or stoning their large prey—and each other—to death. The Neanderthals’ famously robust and muscular physique probably speaks volumes about their lack of cultural complexity, while our gracile and refined appearance trumpets our virtuosity at substituting tools and clever thinking for brute physical force.
The Neanderthals’ stocky build made them well adapted to the cold climates of much of Europe and Eurasia, but the irony is that our species—whose tall and slender bodies were certainly not cold-adapted—replaced the Neanderthals during the Ice Age that engulfed these lands. It seems the Neanderthals simply could not adapt their lifestyle of hunting for large game rapidly enough to the declining populations of large animals that the encroaching ice would cause. But we could, and the difference is probably down to social learning. Or think of it this way. Twenty-eight thousand years ago, the Neanderthals sat in Gibraltar going extinct while gazing across the straits to the warmer climes of Africa clearly visible only eight to ten miles away, but they were unable to make boats to carry them there.
CUMULATIVE ADAPTATION AND
CULTURAL SURVIVAL VEHICLES
THE NEANDERTHALS’ plight reminds us that each of the many biological species on Earth exploits its particular environment, but for the most part it is only that environment that it can occupy. This is because biological species are vehicles built by sets of genes that have evolved together over millions of years to be good at solving the problems posed by a particular environment. For instance, woolly musk oxen are the product of a coalition of genes that natural selection has roped together to produce a vehicle suited to surviving the cold temperatures of Siberia. A different coalition of genes gives rise to camels, a vehicle good at surviving even the scorching deserts of the Sahara; monkeys are vehicles adapted to climbing trees; and the coalitions of genes we call penguins produce a fishlike bird vehicle that can survive the Southern oceans. A camel would make a poor musk ox and a penguin a poor monkey. A cross between a musk ox and a camel—were one possible—probably wouldn’t be much good at being either a camel or a musk ox.
The lesson we learn from this is that there are no real shape-shifters in nature, nor anything like children’s Transformer toys that can change what they are. Being limited to what their coalitions of genes evolved to do, no one species can do everything. That was, of course, until humans came along and rewrote all the rules that had held for billions of years of biological evolution. Here was a single biological species using just a single coalition of genes that was nevertheless able to adopt different guises and forms in different places. In one place we could be like a heron able to pull fish from the sea, in another like a lion able to bring down large prey, in another like a camel able to survive in the desert, and in yet another we could float on the water like a duck or a seagull. Our cultural survival vehicles were built not from coalitions of genes but from coalitions of ideas roped together by cultural evolution. This meant that for the first time a single species was able to spread out and occupy every corner of the world. Where all those species that had gone before us were confined to the particular genetic corner their genes adapted them to, humans had acquired the ability to transform the environment to suit them, by making shelters, or clothing, and working out how to exploit its resources.
It was social learning that made our shape-shifting possible because social learning is to ideas what natural selection is to genes. Both are ways of picking out good solutions from a sea of variety. Natural selection builds complex adaptations like eyes and brains from the successive accumulation over millions of years of many small genetic changes, each one of which improves on its previous form. Equally, social learning builds complex societies by a process of cumulative cultural adaptation as people select the best from among a range of options, improve on them, or blend them with others—what Matt Ridley in his book The Rational Optimist calls “ideas having sex.” And so our knowledge, ideas, technologies, and skills accumulate and build increasingly complex objects. When someone noticed that a club could be combined with a hand ax the first hafted ax was born. When someone tied a vine to the ends of a bent stick, the first bow was born and you can be sure the first arrow soon followed.
The analogy with genetical evolution is deeper than mere words: just as genetical evolution brings together the sets of genes that produce a successful biological species or vehicle for a particular environment, cultural evolution brings together the sets of ideas, technologies, dispositions, beliefs, and skills that over the millennia have produced successful societies, good at competing with others like them, and well adapted culturally to their particular locale. These are our cultural survival vehicles, and it is important to see them as not different in principle from biological vehicles, it is just that the information on which they are based takes a different form: it resides in our minds rather than in our genes. Thus, when people walked into the Arctic and survived, it was because they had acquired the knowledge and technology to make clothes suitable to that harsh environment, to build shelters out of ice, and to fish in the cold Arctic waters. At a later time and different place, when Polynesian people invaded the Pacific, it was because they had acquired the technology to produce seagoing boats, and the knowledge of how to navigate by the stars.
Indeed, we can think of our differing cultural survival vehicles as playing the same ecological role as different biological species. Just as a camel would make a poor musk ox, a Polynesian would not be well equipped to survive the Arctic. But of course our cultures can adapt on the fly and without having to wait for genetic changes to come along, and so the rapid spread of our various cultural species around the world after we left Africa is like a tape of biological evolution speeded up a millionfold or more. Almost everything around us today in our modern world can be attributed to social learning and the cumulative cultural adaptation it propels.
This is not to say our genes played no role in our occupation of the world, just that it was our cultures that took us to its various environments to begin with. When people walked into the Arctic, they began to evolve genetically to have a stocky build that made them better at retaining heat, but it was their culture and not their genes
that took them to the Arctic to begin with. Similarly, the Polynesians would also adapt genetically to their hot and sunny environment by becoming leaner and darker-skinned, but again it was their culture that got them there.
Modern genomic studies of large numbers of people are discovering many small genetic differences among human groups that confer some sort of advantage in their environments. For example, in some European and African societies with a long history of dairying, adults have acquired the ability to digest milk. We have seen how some Tibetan people have acquired an extraordinary capacity to extract oxygen from the air at high altitudes, and how some Han Chinese have an unusual ability to metabolize alcohol. Hunter-gatherer groups exposed to more starch in their diets produce more salivary amylase—an enzyme that begins the process of digestion while food is still being chewed—than those whose diets contain less starch. Differences in facial appearance around the world might be related to arbitrary preferences in the choice of mates.
These are just some of the many small genetic differences among human groups that have arisen as a result of being thrust into environments that our cultures opened up to us. And it is remarkable how quickly we have adapted. The 60,000 to 70,000 years since modern humans spread out of Africa is little more than the blink of an eye when stacked against the 6 to 7 million years that separate us from our Great Ape ancestors. The presence of these genetic differences, however small, tell us that we have had a habit of keeping to ourselves as we spread out around the world, because had we not, our genetic differences would have become blurred. This is not to deny that human groups have always traded with each other, intermarried, fought wars, and traipsed across each other’s territories. But it is only by having a tendency to maintain our identities in separate cultures or tribal groups that natural selection could have sculpted our many differences, and have done so in just the few tens of thousands of years since we walked out of Africa. Then again, we might have guessed this was the case: how else but through a tendency to keep to ourselves in our cultural survival vehicles can we explain a single species that speaks at least 7,000 mutually unintelligible languages?
But why do we behave this way? Could it be that our cultural survival vehicles have evolved tendencies to protect the knowledge and wisdom to which they owe their success?
CULTURES CARVE UP THE LANDSCAPE—LINGUISTICALLY
A WALK along the northeast coast of Papua New Guinea will bring you into contact every five to ten miles with a tribe speaking a different language: in that part of New Guinea you could encounter Korak speakers, quickly followed along the coast by Brem speakers, who in turn are followed by Wanambre speakers, and none of these more than ten miles apart. Each of these tribes is a distinct group of people, making their living alongside each other in the dense forests of that island, and speaking mutually unintelligible languages. If we were to encounter this diversity of languages inside an area of a typical medium-sized town, we might expect to find not just three or more different languages spoken, but three or more distinct groups of people, brought up speaking a different language and living separate lives, each having carved out a portion of the town to live in!
The density of languages in Papua New Guinea strains credulity, but recall how the Papuan man asked if it could be true that the societies which spoke these different languages were this tightly packed together replied, “Oh no, they are far closer together than that.” And it is true, an astonishing figure of over 800 different languages, or about 15 percent of all languages found on Earth, are spoken in the mere 312,000 square miles of the island of New Guinea—with many having only a few thousand speakers. This is an area slightly bigger than the state of Texas. Languages are even more tightly packed in the tiny Polynesian island archipelago of Vanuatu, northwest of Australia. Vanuatu’s islands cover just 4,100 square miles, and yet over 100 distinct languages are spoken on them, each one by an average of just 2,000 speakers. Even this gives a more sedate picture than becomes apparent when one is on the ground in these regions. For instance, the Vanuatu island of Gora covers 132 square miles, and like so many of the islands in this region, it is the roughly circular remnant plug of an ancient volcano. Gora is just twelve to thirteen miles in diameter, but this speck of an island supports five languages—Lakon or Vuré, Olrat, Koro, Dorig, and Nume. This is a density of languages about tenfold higher than that of Papua New Guinea.
Language is one of our defining traits as a species, but we are probably the only animal in which two of its individuals plucked from different places—even right next door—might not be able to communicate with one another, almost as if they were two different biological species. Sometimes, even speakers of the same language can confuse one another: a young English boy I know, travelling in America, was told by someone who overheard him speaking, “I can tell from your accent that you’re from somewhere in Europe.” By comparison to our linguistic isolation, you could take a gorilla from its troop and put it in any other troop anywhere gorillas are found, and it would know what to do. There would probably be some fighting over territory, and attempts at establishing who is dominant over whom, but for the most part life would be routine. The new gorilla would communicate as all gorillas communicate, fight as gorillas fight, make the same kinds of nest, and eat the same kinds of food. There is nothing special about gorillas. This experiment could be repeated with donkeys, or ducks, or goldfish, or frogs, and get much the same outcome.
So, why is it that groups of people in New Guinea, or more generally just about anywhere in the tropics, all more or less living the same lifestyle, divide up their territories so exclusively as to evolve different languages, and sometimes every few miles? What makes this division even more peculiar is that, where different biological species specialize at exploiting different features of the environment—what biologists describe as a species’ niche—in any given area the humans are all occupying more or less the same niche, save for one: human societies seem to have a disposition to acquire their own linguistic niche and then maintain it. The anthropologist Don Kulick describes how
New Guinean communities have purposely fostered linguistic diversity because they have seen language as a highly salient marker of group identity… [they] have cultivated linguistic differences as a way of “exaggerating” themselves in relation to their neighbors… . One community [of Buian language speakers], for instance, switched all its masculine and feminine gender agreements, so that its language’s gender markings were the exact opposite of those of the dialects of the same language spoken in neighboring villages; other communities replaced old words with new ones in order to “be different” from their neighbors’ dialects.
Kulick also relates an account from another linguist of a New Guinean village of Selepet speakers. One day, the community met and collectively decided to change their word for “no” from bia to bune. The reason they gave was that they wanted to be distinct from other Selepet speakers in a neighboring village, and with immediate effect. They have spoken differently ever since. We can only sympathize with the confusion someone would have felt who had gone away hunting for a few days.
There is speculation that humans might be innately programmed to recognize and prefer people who share our language, or that if not innate, the preferences arise very early in life, even before we can speak. By five to six months, infants prefer to look at people whom they have heard speaking their native language. Katherine Kinzler and her colleagues note that
Older infants preferentially accept toys from native-language speakers, and preschool children preferentially select native-language speakers as friends. Variations in accent are sufficient to evoke these social preferences, which are observed in infants before they produce or comprehend speech and are exhibited by children even when they comprehend the foreign-accented speech. Early-developing preferences for native-language speakers may serve as a foundation for later-developing preferences and conflicts among social groups.
Neighboring communities also of course distinguish
themselves in customs, beliefs, art, dance, weaponry, costumes, singing, music, and architecture. For instance, among the nomadic pastoralists of Northern Kenya, the Gabbra people dress simply in muted colors, while their next-door neighbors the Samburu wear vivid red robes, and the nearby Turkana favor dark colors and, among the women, copious amounts of metal jewelry and neck rings that can give them a daunting appearance.
It is a pattern seen all over the world. In the first years of the nineteenth century, the explorers Meriwether Lewis and William Clark made their long trek from the Missouri River all the way to the west coast of America and then back. The lands they walked through were uncharted, and their diaries show they were struck by the sheer number and variety of the Native American tribes they encountered. Dayton Duncan and Ken Burns, in their account Lewis and Clark: The Journey of the Corps of Discovery, write that
the dizzying diversity of Native American life is one of the clearest (though unspoken) images to emerge from [Lewis and Clark’s] journals. The West through which the Corps of Discovery traveled was neither an “uninhabited wilderness” nor a single “Indian world.” Indians thought of themselves as many different people, not as one monolithic group—and understandably so. They were as varied as the western landscape itself… . [Some] roamed the Plains following the buffalo herds, living in tepees that could be moved at a moment’s notice; people who were farmers… lived in permanent villages of rounded earth lodges; people who lived in stick wickiups and dug for roots; people who fished for their food and dwelled in large houses made of wooden planks. Some measured their wealth in horses; others had no horses at all. Some were predominantly tall, or wore forelocks of their hair pushed up as a sign of distinction. Others were shorter, stouter and saw beauty in a forehead flattened by boards.
