Language Is Not a Simple Genetic Matter
It sounds so simple. The title on an article in PhysOrg announced, in Kipling Just-So Story Format, “How gorilla gestures point to evolution of human language.” Because gorillas have an extensive repertoire of over 100 gestures, human conversation was only a matter of evolutionary time. Is this mere storytelling, or do such explanations have scientific validity? Can the changes necessary for human language be found in the genes?
The FOXP2 gene is often singled out as crucial to the evolution of human language, because mutations in that gene lead to speech defects in humans. The recently published Neanderthal genome (see National Geographic News) showed that Neanderthals had the same FOXP2 gene we have. “This gene is involved in linguistic development, suggesting that Neanderthals could talk,” the article said. No one has shown, however, that FOXP2 is a necessary or sufficient cause for the origin of language – such an inference is hopelessly simplistic (see 05/26/2004, 02/21/2008). For example, a defective power supply in a radio that renders it inoperable does not explain the communication heard when it works. Is there more than genetics involved in the origin of our language capacity? How could we know?
Cultural selection and synergy
In an essay in Nature,1 E�rs Szathm�ry and Szabolcs Sz�mad� argued that “Language evolved as part of a uniquely human group of traits, the interdependence of which calls for an integrated approach to the study of brain function.” It’s more than the ability to recognize words. Your dog can do that. They said, “more than any other attribute, language was probably key to the development of the set of traits that makes humans unique.” These two authors proposed that social factors were much more important than genes in the development of language. “Cultural evolution has shown us that one word can be worth a thousand genes,” they said. But how can that explain language in a Darwinian paradigm? It almost sounds Lamarckian – the discredited hypothesis of inheritance of acquired characteristics. Here’s how they tied it in to Darwinism:
That the genes involved in a cognitive trait affect other traits, and have effects that interact with each other, is business as usual for complex behaviour. But the result is likely to be a network of interacting effects, in which evolution in one trait builds on an attribute already modified as a by-product of selection acting on another. The nature of the gene networks underpinning complex behaviour suggests that several genes will have been selected for because they enhanced proficiency in a range of tasks – whether in social, linguistic or tool-use domains.
Language emerged, they said, at the same time humans were learning to fish and hunt big game and make stone tools. It was a by-product of the co-option of existing genes for vocalization being selected for new uses, they suggested. This all happened at a time when major evolutionary changes were occurring simultaneously:
The probable emergence of modern language in the context of these other capacities points to the evolution of a uniquely human set of traits. We’ve barely begun to probe the architecture of this ‘suite’, but there is little to suggest that each capacity evolved one by one, or that they could be lost independently without harming at least some other traits in the set.
But is this explanation helpful for elucidating what actually happened, or does it shield itself from falsification in the noise of complexity? Creationists would say God designed all these traits to work together. These evolutionists did appeal to evidence, but then only for the interdependence of the traits, not their origin: “Evidence supporting the close-knit evolution of traits comes, for example, from experiments showing that people who struggle with grammar also have difficulties drawing hierarchical structures, such as a layered arrangement of matches.” They also said that tool-making and language appear related. But such linkages do not necessarily point to evolution as the only explanation.
Szathm�ry and Sz�mad� used their hypothesis to weave a seamless story of the transition from genetic evolution to cultural evolution:
The evidence strongly suggests that language evolved into its modern form embedded in a group of synergistic traits. However, language almost certainly holds special status over the other traits in the set. More than any other attribute, language is likely to have played a key role in driving genetic and cultural human evolution.
Language enables us to pass on cultural information more efficiently than can any other species. It’s taken about 40 million years, for example, for five agricultural systems to appear in fungus-growing ants. Human agriculture diversified on a massive scale in just a few thousand years. Language makes it easier for people to live in large groups and helps drive cumulative cultural evolution – the build-up of complex belief systems, and the establishment of laws and theories over several generations. It has allowed us to construct a highly altered social and physical world, which has in turn shaped our evolution. Cultural evolution has shown us that one word can be worth a thousand genes. Language was the key evolutionary innovation because it built on important cognitive prerequisites and opened the door to so much else.
It appears they just said that their own reasoning evolved from cultural evolution which evolved from genetic evolution. Can those gaps be bridged so easily? Can one shift the hot potato of explanation between genes and culture as required to keep the story going?
Exaptation: Dissing Darwin
Robert Berwick raised questions about this in a commentary in PNAS,2 “What genes can’t learn about language.” He opened with this very issue: “Human language has long been viewed as a product of both genes and individual external experience or culture, but the key puzzle has always been to assess the relative contribution of each.” He asked whimsically if language evolution is more like hemline fashions (culture) or the fingers on one’s hand (genetics). There must be an interplay of both, because we know every child is born ready to learn a language, but those who learn Hindi cannot understand those who speak Mandarin.
Berwick’s solution leaned toward cultural evolution. The reason is that genetic evolution is too slow to keep up with the rapid changes known to occur in human language. One finding he cited “runs counter to one popular view that these properties of human language were explicitly selected for,… instead pointing to human language as largely adventitious, an exaptation, with many, perhaps most, details driven by culture.” (An exaptation means a trait not acquired by natural selection – presumably through a trait that predisposed a creature toward an adaptation). The upside is that it means the set of genes devoted to language can be greatly reduced. “There is no need, and more critically no informational space, for the genome to blueprint some intricate set of highly-modular, interrelated components for language, just as the genome does not spell out the precise neuron-to-neuron wiring of the developing brain.” The downside is that classical Darwinian natural selection had little to do with it.
Berwick recognized the controversy this position is likely to raise: “such a result may prove surprising to Darwinian enthusiasts who see the hand of natural selection everywhere,” he admitted, but he had an even “more startling” ramification to unleash: a convergence between the views of two groups often at variance with one another: cultural evolutionists and theoretical linguists. Recent models by subsets of these camps can make do with a “minimal human genome for language.” Is this an evolutionary coup?
String Theory and Semantics
One thing remains: explaining the “hallmark of human language,” recursive concatenation. This is our unique ability to combine words into new entities that can be treated as a single object, then combined again over and over. This ability, which provides us “an infinity of possible meaningful signs integrated with the human conceptual system,” is lacking in animals. With it, though, we have “the algebraic closure of a recursive operator over our dictionary.” We have “infinite use of finite means.” How could genes or culture explain this capability? Berwick merely states that it does: “the claim that human language is an exaptation rather than a selected-for adaptation becomes not only much more likely but very nearly inescapable.” Believe it or not.
Actually, the coup is not over yet. Berwick ended with two caveats about “What models can’t tell us about language evolution.” The cultural-evolution model would expect all aspects of human language to rise and fall like hemlines, but “Indeed, as far back as we can discern, human languages have always been just as complicated and fixed along certain dimensions.” There’s a difference, for example, between a sound and its value. There is no necessary connection between what our genes allow us to pronounce and what we mean by the sound. Exaptation merely assumes what it needs to prove: the “promiscuous recursion harnessed to our conceptual dictionary” that makes language so endlessly expressive.
Why Confirm What We Already Know?
The second caveat is even more alarming. Berwick said we can never know how language evolved:
Second, there remain inherent restrictions on our ability to ferret out biological adaptation generally and see into the past, more so than is sometimes generally acknowledged, simply because of limits on what we can measure given the signal-to-noise ratio of evolution by natural selection, and similarly constraining what computer simulations like the one in this issue of PNAS can ever tell us. Since the pioneering study in ref. 11 we know that cultural evolution can sweep through populations as quickly as viral infections. By comparison, evolution by natural selection is orders of magnitude slower and weaker, its effects on gene frequencies easily swamped by the migration of even a few individuals per generation. Practically, this means that although we know without a doubt that adaptive selection has been involved in the shaping of certain traits, language being one of them, the data to establish this fact conclusively remains methodologically out of reach simply because it is infeasible to collect the requisite experimental evidence. To take a far more secure case than language, although we have long known that human blood group differences confer certain reproductive evolutionary advantages, geneticists have estimated we would require the complete age-specific birth and death rate tables for on the order of 50,000 individuals to confirm what must certainly be true. Given the great costs coupled with the relatively small benefits of confirming what we already know, the pragmatic nature of science wins out and there is simply little enthusiasm in carrying forward the exercise.
By portraying language evolution as something “we already know,” Berwick has insulated it from the need for empirical evidence. Indeed, he generalized this to all cases of evolutionary adaptation, not just language. If the signal-to-noise ratio of natural selection is so low as to be undetectable, is evolution a science, or a belief? Notice the phrase “story line” in his ending paragraph:
Consequently, it is probably safe to say that neither this nor any other confirmation of adaptive advantage for one or another particular evolutionary story line about human language, no matter how compelling or how internally consistent its computer simulation logic, will be immediately forthcoming. To be sure, computer simulations can still establish boundary conditions on evolvability via the Balwin�Simpson effect or set directions for further inquiry, and Chater et al. succeed admirably. Nonetheless, we should remain ever alert that there are always restrictions on restrictions, that neither this study nor others like it can tell us how human language actually evolved.
1. E�rs Szathm�ry and Szabolcs Sz�mad�, “Being Human: Language: a social history of words,” Nature 456, 40-41 (6 November 2008) | doi:10.1038/456040a.
2. Robert C. Berwick, “What genes can’t learn about language,” Proceedings of the National Academy of Sciences, February 10, 2009, 106:6, pp 1685-1686, doi:10.1073/pnas.0812871106.
Those last two block quotes are worth reading carefully. For Darwin skeptics, the evidence could hardly be more clear: evolution is a belief imposed on the evidence, not a belief derived from the evidence. Since there is no way they could possibly test their belief, evolutionists begin with the assumption of evolution and work everything into their chosen paradigm: fragmentary evidence, elusive hints of signal in a noise (like the FOXP2 gene, inferences from which are as likely to deceive as enlighten), and copious amounts of imagination and storytelling. Since “we already know” by collective agreement that Darwin reigns and creationism is out, what need have we of proof?, they think. They have tossed verification out the window. Like communist dictators behind a wall, they have awarded themselves offices for life and comfy quarters for speculating endlessly without fear of contradiction. Evidence, like the peasantry, becomes subservient to the State. Damaging evidence has been filtered out by the State-run press. The regime is self-promoting, self-serving, and self-perpetuating.
Time for a revolution.