The origin of language was once a forbidden subject and in 1866, the Linguistic Society of Paris went so far as to ban debates on the subject – because it was considered too speculative to be a matter for serious people! But I find the question fascinating. When and how language developed remains a mystery. But with communication and language being such a clear measure of the distinction between humans and other primates, it seems obvious that there must be some genetic basis for this difference.
Ten years ago this month, a team of University of Oxford scientists published a description of a family who struggled with words. By comparing their DNA, the scientists zeroed in for the first time on a gene associated with language, dubbed FOXP2.
Genetic evidence suggests that the basis of language appeared among hominids prior to the evolutionary split that gave rise to Homo neanderthalensis. Having the genetic wherewithal for having language does not of course prove that hominids had language 400,000 years ago. But I would suggest that the need for a particular characteristic (whether for survival or merely for coping better with the prevailing environment) itself predisposes for those factors which enable the correct expression of the relevant genes to enhance the characteristic. And this leads to the role that epigenetics and the inheritance of factors controlling gene expression – rather than mutations of the genome – may have had in the development of language.
Forkhead box protein P2 also known as FOXP2 is a protein that in humans is encoded by the FOXP2 gene. ….. human FOXP2 differs from chimp FOXP2 by only two amino acids, mouse FOXP2 by only 3 amino acids, and zebra finch FOXP2 by only 7 amino acids. One of the two amino acid difference between human and chimps also arose independently in carnivores and bats. A recent extraction of DNA from Neanderthal bones indicates that Neanderthals had the same version (allele) of the FOXP2 gene as modern humans. …. researchers have speculated that the two amino acid differences between chimps and humans led to the evolution of language in humans.
Revisiting FOXP2 and the origins of language
.. FOXP2 is a transcription factor, which activates some genes while suppressing others. …. Comparisons of gene sequences of modern humans with other living species had put the origins of human FOXP2 between 200,000 and 100,000 years ago, which matches archaeological estimates for the emergence of spoken language. However, Neanderthals split with humans around 400,000 years ago, so the discovery that they share our version of FOXP2 pushes the date of its emergence back at least that far. …
…. The genes that are directed by human FOXP2 are a varied cast of players that influence the development of the head and face, parts of the brain involved in motor skills, the growth of cartilage and connective tissues, and the development of the nervous system. All those roles fit with the idea that our version of FOXP2 has been a lynchpin in evolving the neural circuits and physical structures that are important for speech and language.
The FOXP2 story is far from complete, and every new discovery raises fresh questions just as it answers old ones. Already, this gene has already taught us important lessons about evolution and our place in the natural world. It shows that our much vaunted linguistic skills are more the result of genetic redeployment than out-and-out innovation.
The Language Fossils Buried in Every Cell of Your Body
These findings hint at what happened to FOXP2 in our ancestors. It may have started out hundreds of millions of years ago as a gene that helped regulate the learning of body movements, such as those involved in running, calling, and biting. Later mutations in the gene spurred more neural growth in certain areas of the brain, including the basal ganglia, creating the connections essential for learning and mastering complicated sounds and, eventually, full-blown language.
FOXP2 didn’t give us language all on its own. In our brains, it acts more like a foreman, handing out instructions to at least 84 target genes in the developing basal ganglia. Even this full crew of genes explains language only in part, because the ability to form words is just the beginning. Then comes the higher level of complexity: combining words according to rules of grammar to give them meaning.
And since these epigenetic – or transcription – factors may act on many genes simultaneously the result will generally be a combination of many resultant characteristics of the many transcription factors acting on a multitude of genes. Only one of the resultant characteristics may be the desired one and the new characteristic will be sustained provided the other “collateral” characteristics which are also created are not sufficiently disadvantageous.
The genetic variations among modern humans – all 7,000 million of us – is amazingly small. The superficial variations that do exist (of skin colour, hair colour and texture, eye colour, epicanthic folds for example) have all come about in just the last 100,000 years – or perhaps only 50,000 years depending on when Out of Africa happened. This would suggest that the variations we observe are mainly due to epigenetic effects causing a variation in the expression of certain genes – activating some and blocking others. These epigenetic effects must be selected or enhanced or suppressed by the surrounding environment and can be passed on to offspring. Some of these variations may not in themselves be advantageous for survival but may be a collateral characteristic which appeared as an accompaniment to the development of some other desired or advantageous characteristic. In fact a “collateral” characteristic if it developed “unintentionally” but then imparted particular advantages would cause new forces of selection ( further epigenetic factors) to come into play. Some characteristics that modern humans have and which have proven to be of benefit may well have initially come into being as a “collateral” feature.
And so back to language and the need to communicate. Taking communication to be the intentional and completed transfer of a meaning from one brain to another, language is merely a tool for communication. The existence of language is not a necessary condition for communication. But the only purpose of language is for communication.
When hominids first acquired language (perhaps as a “collateral” characteristic) and later developed language therefore, it must have been in response to a need to communicate with a very strong feedback loop since the increased ability to communicate and its advantages further increased the need to communicate. This further development could well have been through epigenetic factors favouring the strengthening of the language ability. Some have suggested that it was trade between different groups of humans which provided the drive for language development. Certainly increased interaction and the need for cooperation between groups of humans – for whatever reason – would have been a powerful drive for the development of language. Primitive language must first have been a consequence of the need to communicate within a small group because of the advantages (in hunting and foraging and in maintaining the group) that it provided. Even the production of sounds in addition to gestures – which must have come much earlier – would have been driven by a need to communicate with one’s own family or social group or to chase away dangerous outsiders. Even the crying of a baby (or the young of any mammal for that matter) – which is sound without language – is driven by the need to communicate since the cry is of benefit to the baby only if communication actually takes place and someone else responds. The development of grammar and language complexity must then have followed/led the development of the complexity of social interactions. The need for communication could thus have provided the drive for the improvement in the language ability with improved language ability giving rise to increased social complexity and a greater need for communication.
It therefore seems very likely to me that our hunter-gatherer or forager ancestors of 150,000 years ago had more than just some rudimentary language. It seems likely that even 150,000 years ago concepts of time and personal identity were already in place. And considerations of a time that is not just the present or considerations of one’s individuality are already abstract issues. The complexity of their language would then have been sufficient not only for their survival and social needs but possibly also for the beginnings of communicating abstract concepts. There would have been another step-change in level of complexity when the use of symbols and writing were developed – possibly around 50,000 years ago.
Tags: communication needs and language development, FOXP2, Gene, Human, Neanderthal, Origin of language
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October 23, 2011 at 6:09 pm
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