This brings us to what’s become the most controversial part of niche construction theory.
Doing things that have knock-on effects for your own species is one thing. Doing things that have knock-on effects for other species, say the critics, is a horse of another color entirely. Especially if it’s mostly other species that benefit, not your own.
For example, consider photosynthesis, the way in which plants use the energy supplied by sunlight to turn water and carbon dioxide into carbohydrates essential for their growth. In the process, oxygen is released as a by-product. But the chief beneficiaries of this oxygen are not plants, but other living organisms—in fact, every living organism that needs air to breathe. Before plants started, there was nowhere near enough oxygen in earth’s atmosphere to support mobile, energy-hogging creatures once these got any bigger than a single cell. It was only when plants had pushed oxygen levels way higher that multicelled creatures could grow and prosper. The niche that plants had constructed—staying in one place, drawing ingredients from ground and air, and using solar energy to process them—had altered the genetic future not of themselves but of countless other species.
But that isn’t evolution, some biologists protested. Evolution is about individuals that can reproduce themselves. Individuals of the same species, naturally. If the behavior of individual A in species X influences the genes of A’s offspring, that’s one thing. They’re the same genes; you can measure the variance from one generation to another, relate it to behavior, make scientific statements, maybe even predictions. But if the behavior of individual A in species X influences the genes of individual B in species Y and its offspring, there’s no common ground. You don’t have anything objective, like a gene, to measure; you’ve got no physical link between cause and effect. To propose a single theory that covers both processes—the effects of niche construction on the niche-constructing species and the effects of that species’ niche construction on other species—is, according to Dawkins, “pernicious.”
Fortunately, we don’t have to get involved in this argument, because in what follows we’ll be concerned with only one species, or rather one series of species—our own and its immediate ancestors. The only genes involved are those that would eventually produce you and me. Nor do we have to struggle with the high-powered math that Odling-Smee and his colleagues use to justify their ways to population geneticists. All we really need is the take-home message:
It’s not just the species that makes the niche: it’s the niche that also makes the species.
WHERE HUMANS FIT IN
What I dimly perceived in Barcelona (it took me months to figure out all the angles) was that, without niche construction theory, you’d never arrive at any satisfactory explanation of how humans got language.
For quite a while, I’d been aware that one of the greatest weaknesses in language evolution studies was a failure to integrate them into an overall account of how the human species as a whole had evolved. You could read not just papers but whole books on language evolution that had hardly a mention of what human ancestors were like or what they were doing while language evolved. It was as if the authors were writing about how species X got language on planet Y. Or worse, since even on planet Y you’d have some physical constraints, they seemed to be writing about how abstract beings might get language in a Platonic empyrean. Linguists weren’t the only ones who did this, though they were among the worst offenders.
But this couldn’t be right. Language didn’t evolve in a vacuum. It was, it had to be, an evolutionary adaptation, just as much as walking upright, shedding body hair, or getting an opposable thumb. And it’s no longer true to say we don’t know enough about our ancestors to provide any significant input. It’s true that we don’t know enough, period. Unless we can invent a time machine, or find a way to clone those ancestors from fossil DNA—just wild dreams, as things are—we never will know enough. And even if we cloned those ancestors, we couldn’t clone their environment, so there’d always be questions. But we do know enough, right now, to draw broad if sketchy pictures of our past, and use that information to separate plausible from implausible proposals. It isn’t facts that are lacking so much as a way of focusing those facts, putting them into a coherent perspective.
Niche construction looked like that way, not just for language but for human evolution as a whole.
Nowhere is this more apparent than in the field of human culture. Humans and their culture have always presented problems for the life sciences. Human culture, with all its multifaceted complexity, its centrality to all we think and do, seems to be the only thing of its kind in nature. And our science just doesn’t know how to proceed with a population of one.
Of course there are those who claim that some animals do have cultures. If you define culture as they do, in terms of the passing on from one animal to another of some learned behavior, that’s trivially true. Like the Japanese macaque monkeys, one of whom learned to wash sand off potatoes before eating them; other monkeys, observing this, followed suit, and it became a custom. Or the chimpanzees of the Ivory Coast, who break open palm nuts and show their children how to do it. But these “animal cultures” are so limited, so impoverished, compared with the immense and constantly expanding human complex of traditions and stories and arts and artifacts and sciences, that any comparison looks like a desperate attempt to carry out some kind of agenda.
As indeed it is. For millennia, religions have been telling us that humans are a special creation, something set divinely apart from the rest of nature. Now that we know that this is false, the pendulum has swung to the other extreme. Rationalists eager to prove their faith feel obliged to insist, despite massive evidence to the contrary, that humans are no different from any other species. Any trait we have, other species too must have, and if that trait isn’t as developed as it is in our version—if potato-washing and nut-cracking don’t quite measure up to an Einstein equation or a Beethoven sonata—well, that’s about how our swimming rates alongside a dolphin’s swimming, or how our ability to locate things through the heat they give off compares with the same ability in pit vipers. Every species has things it’s better at than others, and who are we to decide that our best tricks have somehow more intrinsic worth than the best tricks of others?
Ironically, niche construction theory links humans with other creatures in a far broader and more valid way than any claims about chimp culture.
Human culture is simply a case of niche construction.
LEARNING VERSUS INSTINCT—DOES IT REALLY MATTER?
Once, when I knew no better, when niche construction theory was hardly even a twinkle in John Odling-Smee’s eye, I wrote, under the influence of George Williams and his like, “While other species adapt to the environment, we adapt the environment to ourselves.” Now I know better. I know that many, perhaps even most, other species adapt the environment to their own needs, insofar as they have the ability to do so. Some don’t have very much ability. We have more than any other species, but what we’re doing is basically the same as what they’re doing.
We build huge climate-controlled buildings to protect us from the heat of summer and the cold of winter. So do termites. They build mounds whose size, relative to that of their builders, is proportionately far larger than the size of our skyscrapers. They regulate the temperature of their mounds in a variety of ways; by positioning them on a north-south axis (thus limiting exposure to midday heat), by building thick outer walls, by plugging entrances at night, and by incorporating a number of air-conditioning devices: ventilation chambers, cooling vanes, air ducts, and chimneys. They also add mushroom- or cone-shaped structures to their mounds to ensure that rainwater doesn’t get into them.
We have developed complex forms of agriculture to supply ourselves with food far in excess of what nature alone could furnish. So have leaf-cutter ants. Leaf-cutters create huge underground farms; in making just one of these they can shift anything up to forty or fifty tons (yes, tons!) of soil. Such a farm
may employ a workforce far more numerous than that of any human enterprise (except perhaps Wal-Mart or the Chinese army). These workers climb plants, cut off leaves, carry the leaves to the farm, drag them down into special chambers, chew them to pulp, arrange them in beds, impregnate them with a moldlike form of fungus, weed the beds, and then gather and distribute the mature fungus to their nestmates.
Well, you may say, ants and termites do these things by instinct; we do them by learning. If you took illiterates from the Arabian desert or the Amazon jungle, people who’d never had any contact with an advanced technological society, and trained them to do such things, they’d do them. But you can’t train an ant or a termite to do anything.
True, but irrelevant. Instinct is simply behavior stamped into the genes. Ants and termites had to start doing the things they do (in some much simpler and more rudimentary way, of course) with the genes they already had, before the interaction of genes and behavior could kick in to eventually produce complex new behaviors. Just as we had to start building crude temporary shelters of stones and brushwood long before we could erect cathedrals and high-rise apartments. Just as we had to start gathering and chewing wild seeds long before we could get to cover a large chunk of the earth with our crops. It was never the case that someone said, “Hey, guys, hunting and gathering sucks—isn’t it time we tried farming?”
The truth is, we gradually and quite accidentally stumbled into agriculture, and so did ants. The difference is that our capacity for learning new things and passing them on to others (a capacity based entirely on our command of language, as we’ll see in the final chapters) made us able to develop far faster than any other species—we could construct our niches without having to wait on interminable rounds of feedback between genes and behavior. But apart from that, the motivation, the process of niche construction itself, and even, as we just saw, some of its specific results, are similar across species, even species as remote from one another as termites and we are.
Indeed, the habits and artifacts of bees and termites resemble human niche construction much more than does nut-cracking by chimps or potato-washing by monkeys. Accordingly, niche construction links us more firmly to the rest of nature than any claim about “animal cultures” can. Indeed, when you come to think about it, people who make such claims are simply following the homocentric bias I’ve referred to in earlier chapters.
Why should the capacity for cultural learning be rated so highly? Because it’s something that’s shared, to a very limited extent, only by those species most similar to ours and most closely related to ours. In other words, those who seek desperately for evidence of “culture” in other animals are simply looking for humanlike traits in those animals. They’re judging other species by human criteria. Let’s face it—vigorously though they’ll deny the accusation, they’re just humanists in drag.
Niche construction is neutral. It enables us to compare the activities of species, including our own, in a completely objective and impartial fashion. And moreover, the study of human niche construction will show that this same hyperdevelopment of learned behaviors is itself based on an instinct: the language instinct.
For language is a prime example of niche construction, arising out of a specific niche and enabling us to construct more and more elaborate niches. It began as a behavior that drove genetic change and continued as a series of genetic changes that drove behavior. Is language cultural or biological? It’s a truism to say “both,” but while scholars have fought for generations over what biology contributes and what culture contributes, few have looked at how biology and culture might have interacted with each other over time to create the kind of language we have today. That’s largely because there was no kind of framework, nothing like niche construction theory, that would have allowed them to frame the issues in more productive ways.
In fact, niche construction happens to be just the right kind of framework for examining how language was born. As noted in chapter 1, we have to explain not just why we have language but why all other species don’t, so we must seek the origins of language not in things we share with other species but in things that make us different. And I said at the beginning of this chapter that there must be some large but hidden difference between apes and us. That difference could hardly lie in genetic material, since ours is almost identical with theirs. It was much likelier to exist in the niche, or rather niches, that human ancestors constructed, for these were very different from the niches of all the other great apes. Therefore somewhere, in one or other of those niches, the difference that gave us language must surely lie.
In the remainder of this book, we’ll review the story of our ancestors and how they came by language in the light shed by niche construction theory; we’ll find that crucial difference; and in the process we’ll learn new and exciting things, not just about language but about the whole process of becoming human.
6
OUR ANCESTORS
IN THEIR NICHES
WHAT A DIFFERENCE A NICHE MAKES!
What makes us different from our closest relatives, the bonobos and chimps in whose company we spent most of chapters 3 and 4, is the series of niches our ancestors developed. This series contained at least six distinct niches: a terrestrial omnivore niche, a low-end scavenging niche, a high-end scavenging niche, a hunting-and-gathering niche, a herding niche, and an agricultural niche. You could add an urban-industrial niche, if you like, to make seven.
In contrast, the bonobo-chimpanzee line may have developed no more than one new niche since the split from our last common ancestor. At least there’s no evidence for more than one. On the other hand, there’s ample evidence that human ancestors constructed new niches on an unprecedented scale and at an unprecedented speed. This has to be what made our fate so different from that of the other great apes.
What I’ve just told you isn’t the story you would have gotten until very recently. Until very recently you would have been told that changing environments selected from genes, and changing climates selected for flexibility, and this combination made human ancestors smarter, so they made tools, and then better tools, because they got smarter still—end of story.
And here’s what we typically learn about the mechanics of that evolution from quasi-popular sources, which merely distill and encapsulate the scholarly sources (this extract is from the MSN Encarta website, but you can find similar stuff all over the place): “Over time, genetic change can alter a species’s overall way of life, such as what it eats, how it grows, and where it can live. Genetic changes can improve the ability of organisms to survive, reproduce, and, in animals, raise offspring. This process is called adaptation . . . Many factors can favor new adaptations, but changes in the environment often play a role. Ancestral human species adapted to new environments as their genes changed, altering their anatomy (physical body structure), physiology (bodily functions, such as digestion), and behavior” (my italics).
Not a word about niches, or about any proactive role the ancestors themselves might have played in all this. No suggestion that animals, including our ancestors, could have decided for themselves what they would eat and where they would live, without waiting for genetic changes to adapt them to it (whatever “it” was). No suggestion that they might have explored new environments and begun to adapt those environments to themselves with the help of genes they already had. And no hint at all as to how language began.
The gene-centered version of evolution cannot explain how language evolved. I don’t mean just hasn’t explained it, or can’t explain it yet; I mean it can’t explain language evolution in principle.
Despite all the recent brouhaha over the FOXP2 gene, nobody as yet has found a “gene for language,” and they likely never will. The highest probability is that language nowadays results from the interaction of a set of pleiotropic genes, that is, a set of several genes each of which performs several different functions in development. One or more of those other, nonlinguistic functions was almost certainly what
each “language” gene was originally selected for. After all, humans have less than twice the number of genes that nematodes have, and since nature seldom throws stuff away, many of these are still the same genes—and whatever nematodes use them for, it sure ain’t language. Recent developments in biology have shown us that genes are far more flexible than was originally thought, able to change their expression to yield a variety of results. And in previous chapters we looked at some very good reasons why the beginning of language need not have involved anything in the way of genetic change.
Language is a living proof of niche construction theory. We’ll see why as we proceed to rewrite our own prehistory from a niche-centered perspective.
IN THE BEGINNING
We don’t, unfortunately, know what was the last common ancestor of us and the chimps. More to the point, we don’t even know what that ancestor was like.
A natural assumption is that it was more or less like a contemporary ape. That would give us a simple story: we changed, apes didn’t. It’s plausible, but there’s really no evidence for what the ancestor looked like or how it lived. And we know that there are sharp behavioral differences between chimpanzees and bonobos, which separated only a couple of million years ago.
Adam's Tongue: How Humans Made Language, How Language Made Humans Page 13
