by Mark Pagel
We cannot of course be sure that the Neanderthals lacked language, but this line of genetic reasoning combined with the Neanderthals’ relative lack of cultural sophistication compared to our own—sophistication that we associate with social learning—points to the conclusion that language evolved with the arrival of our own species. Our capacity for language was almost certainly present in our common ancestor because today all humans speak and speak equally well. There are no languages that are superior to others and no human groups that speak primitive as opposed to advanced languages. This would make language no more than around 160,000 to 200,000 years old, although some anthropologists think language arose even later than this, pointing to the sharp increase beginning around 70,000 to 100,000 years ago in evidence of our symbolic thinking and the complexity of our societies. It is just possible that all modern humans alive today trace their ancestry back to common ancestors who lived around that time, so language evolving at this later date, though unlikely, is possible.
Whenever language emerged, it probably built on what had been a series of developments in our ancestors of what we might think of as proto-languages, backed up by the physical apparatus to make languagelike sounds. Our language capacity might have grown out of ancient primate abilities to vocalize and gesture, and probably required a capacity to string ideas together in chains, and to anticipate what others might be thinking. Tecumseh Fitch in The Evolution of Language describes how the early proto-languages might have contained just a few isolated words with very little in the way of grammar. Thus, pointing and making a few sounds might have slowly evolved into that sound coming to be associated with whatever was being pointed at, and the first noun was born. Making a different sound while perhaps stabbing a spear at that same thing—maybe a wildebeest—could have given rise to the first verb. Put these two together and the first primitive sentence was born: “Stab wildebeest!” It wouldn’t take long for pronouns to arise as a way of getting someone to do your stabbing for you, and “You stab wildebeest!” might have been heard echoing across the savannah.
Still, why did language wait to make its appearance in our species, and not earlier or in any other species? A hint might be found in the quite remarkable lack of social complexity of the Homo species that preceded us. The lesson of these species is that in trying to explain the appearance of language we should look for the need for it, not just to pieces of anatomy or to genes. Evolution doesn’t just produce complex adaptations like language, hand them to a species, and then sit back and see what they do with them. There must be something that is pulling the trait along so that it pays its way by granting some advantage to its bearers.
To most people, the advantage of having language is obvious—it allows us to communicate. This is true, but we need a theory or explanation that tells us why we have language and no other species does. Indeed, it is not even clear that “communicating” on its own is sufficient to get language to evolve in us or any other species. This is because it is only by granting its bearers some individual advantage that natural selection can get a trait to evolve. But when it comes to language, this leads to two evolutionary predicaments. One is that much of what I have to say might benefit you, and potentially at a cost to me. Thus, if I tell you what plants can be used to make poison to put on your arrowheads, you might not only kill more prey than me, you and your family might even manage to kill what few there are before I do. Natural selection never promotes naive altruism, so surely this will favor people who keep their mouths shut, and language will die a silent death. On the other hand, maybe I can instead use my language to mislead or trick you. Now my actions are no longer altruistic and indeed might help me at your expense. But this poses the second predicament. If you know that my acts of communication are designed to benefit me, surely this favors people who don’t listen. And even if you do listen, why should you believe me? Talk is, as they say, cheap.
But wait, what if I tell you I will teach you how to get poisons from plants if you teach me how to make a better arrow? Or, what if one day out on the tundra you have acted with great courage in bringing down a mammoth, and back in the village, I make sure word of your exploits travels fast, hoping you will give me more than my share of the meat? Or maybe you and I hatch a plot along with seven of our friends to raid the neighboring village. These are all social actions that involve the exchange of ideas, striking deals, and coordinating activities, and they depend on trust and reputations. They are also things that only we humans do; in fact, cooperation of this sort has been our species’ secret weapon, returning enormous benefits and making our cultural groups formidable and fearsome competitors. We have acquired an entire psychology geared to making our style of cooperation work and to protect us from the risks inherent in even the simplest acts of reciprocal exchanges with others who might try to take advantage of our good will.
And this now gives us an insight into why language evolved because we have quietly ignored the fact that we couldn’t undertake any of these acts of cooperation without it. Language evolved to solve the crisis that began when our species acquired social learning—probably some time around 160,000 to 200,000 years ago—and immediately had to confront the problem of “visual theft.” Remember that was the crisis that arose when humans became able to copy each other’s best ideas. Language solves this crisis by being the conduit that carries the information our species needs to reach agreements and share ideas, and, as we saw earlier, it makes the “marketplace of reputation” possible. It disarms our conflicts and turns them toward our advantage. This requires something more than the bleats, chirrups, roars, chest thumping, odors, and bright colors of the rest of the animal kingdom. Our social complexity depends on language: without it we might still be living like the Neanderthals were when we first entered Europe sometime around 40,000 years ago.
Both evolutionary predicaments are solved. You and I can use language to arrange and negotiate the terms of an exchange of information, goods, or services that brings benefits to both of us. These are reasons for me to speak and for you to listen. But words are cheap, so how can you trust mine? You can’t, and you will know that I might try to use language to acquire more than my share of the benefits of our exchanges. Still, language provides you with a trait that you can use to “police” my actions. If I fail to keep up my end of the bargain, you can break off our partnership and quickly, widely, and spitefully spread the word that I am not to be trusted. This spite is cheap for you and might bring benefits your way by convincing other cooperators to work with you rather than with me. On the other hand, you must exercise your spite carefully lest you develop a reputation as someone who spreads false rumors. Actions might speak louder than words but words travel faster and further. Language “watches” and regulates our social behavior, and in a way that dictators armed with arrays of CCTV cameras could only dream of.
Contrary to what most of us probably take for granted, then, it is not the main function of language merely to communicate, as when, say, two computers send information back and forth. Rather, language evolved as a self-interested piece of social technology for enhancing the returns we get from cooperation inside the survival vehicles of our cultures. And this answers the question of why we are the only species to have it: we are the only species with language because the unique nature of our social systems means we are the only species with something to talk about. Thus, when we watch animated films with talking squirrels, deer, bears, rabbits, and other animals, it is not just their language that is out of place, it is their behavior: these animals are acting like humans. They are making plans, coordinating their actions, cooperating, and trading with each other, the very things other animals don’t do. In Kenneth Grahame’s Wind in the Willows, when Mole, Badger, and Ratty go to Toad Hall to try to convince Toad to change his errant ways, they are not acting like badgers, water rats, and moles. Real badgers, water rats, and moles don’t visit country homes, row in boats, tend gardens, live in houses, or do many of the other things in that char
ming book—they don’t even have names!
Thinking of language as a trait for promoting cooperation might give us insight into what the great, but sometimes exasperatingly gnomic, philosopher Ludwig Wittgenstein meant when he said, “If a lion could speak we could not understand him.” Maybe it is this: if a lion could speak it would not be a lion, but something more like us—we wouldn’t understand it as a lion. We wouldn’t understand it as a lion because lions behaving as lions don’t really have much to discuss beyond what they already achieve with their forms of communication. If they did have more to discuss, they wouldn’t be lions, but something more like Mole, Badger, and Ratty. In fact, most of the communication in animal social systems is about signaling location, or who is dominant to whom, or disputes about food, territory, or mates. These are issues that can be settled by signals of grunts, chirps, whistles, odors, chest-thumping and head-butting, bites and grimaces, and that is why animals have these systems of communication rather than language. Why talk when a roar will suffice?
An unforgettable passage from Alexander Kinglake’s Eothen captures the sense in which language is not merely for communicating. Meaning “from the East,” Eothen is a first-person account of this young Englishman’s Grand Tour of the Near East in 1834. Kinglake decided to travel by camel across the Sinai to Cairo, accompanied by a servant. After being out in the desert for several days, he describes seeing
a mere moving speck on the horizon… . Soon it appeared that three laden camels were approaching, and that two of them carried riders; in a little while we saw that one of the riders wore European dress, and at last the riders were pronounced to be an English gentleman and his servant… . As we approached each other, it became with me a question whether we should speak. I thought it likely that the stranger would accost me and in the event of his doing so I was quite ready to be as sociable and chatty as I could be, according to my nature; but still I could not think of anything particular that I had to say to him. Of course, among civilized people, the not having anything to say is no excuse at all for not speaking, but I was shy and indolent, and felt no great wish to stop and chat like a morning visitor in the midst of those broad solitudes. The traveler perhaps felt as I did, for, except that we lifted our hands to our caps and waved our arms in courtesy, we passed each other quite as distantly as if we had passed in Bond Street. [italics added]
As it turns out, the two protagonists eventually did speak, but only because their camels slowed up and turned around! Even then, the other man’s greeting was the meager “I dare say you wish to know how the Plague is going on at Cairo?”
It is little short of extraordinary that these two ships could almost pass in the night without speaking to each other, and strains credulity when we appreciate the setting. Kinglake’s only partly ironic use of the word “accost” to describe being spoken to tells us something of the diffident and private character of Englishmen of his day (not entirely extinct even now). But there is something more to this example than reserve. Kinglake is right: there is an element of being accosted when one is spoken to out of the blue, and this is precisely because language can zero in so quickly on matters that we might wish to keep private, matters that were they made public could damage our reputation, give away our plans or simply provide information to someone that could benefit them at our expense. Not knowing the other man on the camel, Kinglake might have concluded that he really didn’t have anything to say to him. Confronted with the same realization, the other man did what we all do when we have nothing to talk about: his remark was the equivalent of talking about the weather.
LANGUAGE, DNA, AND REGULATION
IN THIS section I want to examine a remarkable similarity between the nature of human language and an unusual feature of our genetic systems. That similarity is that both evolved specifically to promote replicators’ interests within their vehicles—genes in their bodies on the one hand, and people in their societies on the other. Thus, we will see that the nature of our language is precisely what we would expect of a system that evolved to allow us to vary our expression—or the way we are seen—inside our cultural survival vehicles, and in a way that benefits us, just as genes can vary their expression inside our bodies in ways that benefit them. Understanding this similarity will explain why human language had to be different from all other forms of animal communication and why it had to adopt a form that we also find in our genes.
To begin this story, we need to appreciate a puzzling feature of our genetic inheritance. Our genomes represent the sum total of the genetic information on our twenty-three pairs of chromosomes. In our species, these chromosomes contain somewhere around 21,000 genes. What is perhaps surprising is that this is scarcely more than the 19,000 genes in Caenorhabditis elegans, a small worm about 1/32 of an inch long that lives in soil; the 15,000 genes of a fruit fly; and only four times more than the number of genes in a yeast, which is just a simple microscopic single-celled organism that causes your fruit to ferment. In spite of having similar numbers of genes to the two animals, our bodies are almost unimaginably more complicated, comprising trillions of cells making an uncountable number of connections, and building hundreds of different kinds of tissues, from eyes and muscles, to hearts (a special kind of muscle), to kidneys. Our brains alone account for many hundreds of billions of these cells, and counting the connections they make to each other is something like trying to count all the stars in the universe. By comparison, C. elegans’ body is composed of fewer than 1,000 cells. And yeast of course doesn’t even have cells (just the single cell), much less arms or legs, digestive tracts, blood vessels, or brains.
We learn two unexpected lessons from this: one is that we are woefully underspecified. Our genes alone cannot possibly carry enough information to specify all the connections that make up our bodies. The other is that an organism’s complexity seems not to be related in any obvious way to how many genes it has. How, then, do we achieve our vastly greater biological complexity than a simple worm or fruit fly? The answer appears to reside in how we use our genes, and not in how many we have. For instance, all mammals have about the same number of genes, and yet they differ remarkably in how they have used them to produce their different sizes, shapes, and capabilities. How we use our genes is why we can share over 98 percent of our genes with chimpanzees but differ so utterly from them. We even have over 80 percent of our genes in common with mice, and 75 percent in common with the much-loved marsupial, the platypus. Moving outside of the mammals, you share 60 percent of your genes with a fruit fly, and even 50 percent with bananas!
A mysterious feature of our genomes that we might think of as their “dark matter”—that as-yet-unidentified substance that is thought to account for a majority of the matter in the universe—is emerging as a principal reason why we can share so many genes with these other species and yet be so different. The common view of our genomes as being packed with genes that provide the instructions to make our bodies turns out to be only a small part of the story. Our genomes contain vast stretches of DNA that are not organized into genes, and are not used for making the protein building blocks of our bodies. This is the dark matter, better known as “junk DNA,” and it comprises a startling 99 percent of our genome, and the genomes of most other “higher” organisms. It is extraordinary but true that only about 1 percent of our genomes is made up of the things we normally think of when we talk about genes. Junk DNA’s existence had been appreciated since the early part of the twentieth century, but the discovery in the late 1970s that it was present in such vast quantities was seen as “mildly shocking” even by the editor of the prestigious scientific journal Nature.
Much of the junk DNA exists in the form of small genetic parasites called transposons that can infect our genomes in much the same sense that a virus infects our bodies. They go by names such as LINE-1 (long interspersed nuclear element), SINE (short interspersed nuclear element), P-elements, and Mariner. They derive the name transposon from their capability to make a copy of themsel
ves that gets inserted at a different place in the genome. They have been present in plants and animals for millions of years, being inherited from generation to generation and even from species to species as new species arise from old. What these genetic parasites all have in common is, like any good replicator, they are good at getting themselves copied. This is the way they reproduce, and they will do this simply because it is what they have evolved to do in competition with other transposons. They are doing this inside your body as you read this, and it is an inevitable fact of natural selection that, once transposons exist, your genome will fill up with the ones best at reproducing themselves.
It has long been a puzzle why we put up with junk DNA rather than evolve ways to remove it. One answer is that most of the time the parasites don’t affect us, they merely accumulate inside our genomes. Even then, we still have to carry this extra DNA around and replicate it along with our genes whenever one of our cells divides. Worse, on rare occasions, when one of our transposons makes a copy of itself, that new copy can get inserted inside one of our genes. This can disrupt the gene’s normal function and sometimes cause harmful effects. Some unusual cases of hemophilia and even of bowel cancer have been blamed on LINE-1 transposons moving around inside our genomes. In fact, we now know that we have evolved “genomic immune systems” to help control transposons, much as we have bloodborne immune systems that help us fight off diseases and infections. Still, the junk DNA accumulates in our genomes because our genomic immune systems don’t catch them all and because they typically don’t remove the junk DNA, just render it inert.
