Language driven by culture, not biology

Jan 20, 2009

(PhysOrg.com) -- Language in humans has evolved culturally rather than genetically, according to a study by UCL (University College London) and US researchers. By modelling the ways in which genes for language might have evolved alongside language itself, the study showed that genetic adaptation to language would be highly unlikely, as cultural conventions change much more rapidly than genes. Thus, the biological machinery upon which human language is built appears to predate the emergence of language.

According to a phenomenon known as the Baldwin effect, characteristics that are learned or developed over a lifespan may become gradually encoded in the genome over many generations, because organisms with a stronger predisposition to acquire a trait have a selective advantage. Over generations, the amount of environmental exposure required to develop the trait decreases, and eventually no environmental exposure may be needed - the trait is genetically encoded.

An example of the Baldwin effect is the development of calluses on the keels and sterna of ostriches. The calluses may initially have developed in response to abrasion where the keel and sterna touch the ground during sitting. Natural selection then favored individuals that could develop calluses more rapidly, until callus development became triggered within the embryo and could occur without environmental stimulation. The PNAS paper explored circumstances under which a similar evolutionary mechanism could genetically assimilate properties of language - a theory that has been widely favoured by those arguing for the existence of ‘language genes’.

The study modelled ways in which genes encoding language-specific properties could have coevolved with language itself. The key finding was that genes for language could have coevolved only in a highly stable linguistic environment; a rapidly changing linguistic environment would not provide a stable target for natural selection. Thus, a biological endowment could not coevolve with properties of language that began as learned cultural conventions, because cultural conventions change much more rapidly than genes.

The authors conclude that it is unlikely that humans possess a genetic ‘language module’ which has evolved by natural selection. The genetic basis of human language appears to primarily predate the emergence of language.

The conclusion is reinforced by the observation that had such adaptation occurred in the human lineage, these processes would have operated independently on modern human populations as they spread throughout Africa and the rest of the world over the last 100,000 years. If this were so, genetic populations should have coevolved with their own language groups, leading to divergent and mutually incompatible language modules. Linguists have found no evidence of this, however; for example, native Australasian populations have been largely isolated for 50,000 years but learn European languages readily.

Professor Nick Chater, UCL Cognitive, Perceptual and Brain Sciences, says: “Language is uniquely human. But does this uniqueness stem from biology or culture? This question is central to our understanding of what it is to be human, and has fundamental implications for the relationship between genes and culture. Our paper uncovers a paradox at the heart of theories about the evolutionary origin and genetic basis of human language - although we have appear to have a genetic predisposition towards language, human language has evolved far more quickly than our genes could keep up with, suggesting that language is shaped and driven by culture rather than biology.

“The linguistic environment is continually changing; indeed, linguistic change is vastly more rapid than genetic change. For example, the entire Indo-European language group has diverged in less than 10,000 years. Our simulations show the evolutionary impact of such rapid linguistic change: genes cannot evolve fast enough to keep up with this ‘moving target’.

“Of course, co-evolution between genes and culture can occur. For example, lactose tolerance appears to have co-evolved with dairying. But dairying involves a stable change to the nutritional environment, positively selecting the gene for lactose tolerance, unlike the fast-changing linguistic environment. Our simulations show that this kind of co-evolution can only occur when language change is offset by very strong genetic pressure. Under these conditions of extreme pressure, language rapidly evolves to reflect pre-existing biases, whether the genes are subject to natural selection or not. Thus, co-evolution only occurs when the language is already almost entirely genetically encoded. We conclude that slow-changing genes can drive the structure of a fast-changing language, but not the reverse.

“But if universal grammar did not evolve by natural selection, how could it have arisen? Our findings suggest that language must be a culturally evolved system, not a product of biological adaption. This is consistent with current theories that language arose from the unique human capacity for social intelligence.”

Paper: ‘Restrictions on biological adaptation in language evolution’ by Nick Chater, Florencia Reali, and Morten Christiansen, is published in the Proceedings of the National Academy of Sciences (PNAS).

Provided by University College London

Explore further: Canola flowers faster with heat genes

add to favorites email to friend print save as pdf

Related Stories

Mars, Saturn and the claws of Scorpius

20 minutes ago

Look up at the night sky this week and you'll find Mars and Saturn together in the west. Mars stands out with its reddish colouring and you might just be able to detect a faint yellow tinge to Saturn. ...

Freedom and responsibility of science

30 minutes ago

Yesterday, the German Research Foundation (DFG) and the Leopoldina National Academy of Sciences presented their recommendations for "The Freedom and Responsibility of Science" in Berlin. Both research organizations appeal ...

The ethics of driverless cars

50 minutes ago

Jason Millar, a PhD Candidate in the Department of Philosophy, spends a lot of time thinking about driverless cars. Though you aren't likely to be able to buy them for 10 years, he says there are a number ...

Recommended for you

Of bees, mites, and viruses

6 hours ago

Honeybee colonies are dying at alarming rates worldwide. A variety of factors have been proposed to explain their decline, but the exact cause—and how bees can be saved—remains unclear. An article published on August ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

chrisssss
not rated yet Jan 21, 2009
The IDM model (http://members.ii...ain.html ) covers a generic set of categories covering classes of meaning derived at the neurology level oscillations and introducing basic sensations of wholeness, partness, static relatedness, dynamic relatedness and their composites. It takes recursion to develop these categories into forms that can be used to represent 'all there is' through use of analogy - as such the emerging set of categories reaches a level where the set can describe itself by reference to itself through analogy, it becomes autological and so representative of a language.

Work with primitive tribes (e.g. in the Amazon jungles etc) as well with infants developing language indicate that social demands for finer distinctions in communicating elicit more recursions and so increase the set of classes of meaning to then be tied to context by some ad-hoc label or else a learnt label (education stops/limits the emergence of creole-style languages by this imposition of the labels of previous generations on the present).

The ability to derive an abstract domain model from analysis of the neurology and then map through that model specialist domain models and so allowing the translation of one to the other, brings out the hard-coding of 'language' in the form of neural oscillations that, given a demanding local context, create refined classes of meanings shows the dynamic of nature (genes) AND nurture (environment).

Language emerges from mediation dynamics and is manifest in the development of consciousness as a proactive agent of mediation where mediation in the neurology goes all the way down to mindless, reactive, basic chemistry of oscillations and enzyme dynamics.

When the article asserts: "the study showed that genetic adaptation to language would be highly unlikely, as cultural conventions change much more rapidly than genes." it shows a lack of thought in considering the dynamics of language in the first place, the first culture. Given the manner in which the brain deals with the new/complex, through oscillations across the brain asymmetry, it is easy to map out basic seeding of language from recursion with the sudden 'jump' from vague categories to rich categories usable for literal and figurative communications shows the hard-coding of such (in that the oscillations are part of the neurology's nature. From that comes the categories as does memory etc etc)

The recursion of the brain manifest in oscillations elicits basic categories of meaning for ALL neuron-dependent life forms and so an ease in learning the particulars of a collective for precise communications. What is then essential is (a) a demanding context to refine distinctions and so increase precision in describing environment as well as self, and (b) a rich set of neurons and especially connectivities where such is achieved in humans through their lengthy development phase.

The IDM model brings out the SAMENESS across all species members and the local context adaptations of classes of meanings to instances of such through ad-oc label creation and teaching of such to later generations. Thus the diversities of local languages cover difference as does the sameness of noun/verb distinctions cover the same patterns in general seeding all languages (recurse the noun/verb dichotomy and out will pop a dimension of classes of meanings mixing the elements of that dichotomy and local context customises such to create small world networks of languages).