April 21, 2009

Political complexity and the spread of ethnolinguistic groups

Gene Expression points me to a new paper on the spread of languages. From the paper:
In particular we have shown that the largest single factor predicting the area over which a language is spoken is the degree of political complexity exhibited by the society speaking that language. This is consistent with the hypothesis that more complex societies replace or incorporate less complex groups and thus spread their languages over larger areas. As political complexity is a property of groups, and
competition often occurs between groups, rather than just between individuals, if more politically complex groups tend to replace or incorporate others, then the proportion of more politically complex societies will tend to increase over time. Such a mechanism represents a process of cultural group selection (21, 48). An interesting area for future research will be to assess the impact this process has on the biological fitness of individuals within groups (49). Increasing political complexity is almost
always associated with greater degrees of social stratification, and wealth in the form of tax or tribute is often extracted by political elites from those lower down the social order (24), which could clearly have significant reproductive consequences for individuals at different levels in such societies. It will be important to assess empirically whether these costs are outweighed by benefits gained from being a member of such a group and from the advantage held in competition between groups.
PNAS doi:10.1073/pnas.0804698106

Political complexity predicts the spread of ethnolinguistic groups

Thomas E. Currie and Ruth Mace


Human languages show a remarkable degree of variation in the area they cover. However, the factors governing the distribution of human cultural groups such as languages are not well understood. While previous studies have examined the role of a number of environmental variables the importance of cultural factors has not been systematically addressed. Here we use a geographical information system (GIS) to integrate information about languages with environmental, ecological, and ethnographic data to test a number of hypotheses that have been proposed to explain the global distribution of languages. We show that the degree of political complexity and type of subsistence strategy exhibited by societies are important predictors of the area covered by a language. Political complexity is also strongly associated with the latitudinal gradient in language area, whereas subsistence strategy is not. We argue that a process of cultural group selection favoring more complex societies may have been important in shaping the present-day global distribution of language diversity.



Maju said...

On first sight is kind of obvious: like "discovering America" today.

But on second thought, I question the idea of "political complexity" and suspect it should be replaced by that of "centralization of power". In other words: the state and its extension in space and time.

At least in the example of Russia it seems pretty obvious: the fact is that the Russian state expanded and the Russian language expanded with it (same for China or the Roman Empire). I think it would be difficult to judge that Russia was more "politically complex" than the Golden Horde for instance. At times one was more powerful and at times it was the other. In the end Russia succeeded but at one time it was just a vassal of the Mongols, who mostly lacked interest in that peripheric septentrional area to bother annexing it.

I would not really be able to argue either that Arabia peninsula had through most of history greater political complexity than the Fertile Crescent, yet the later appears more linguistically diverse.

Some of the areas where higher linguistic diversity appears to exist (not very sure about the correctness of it) probably were not lacking political complexity at all through history but actually were border areas between two or more powerful (politically complex) states. The area near the Rhin in Europe is one of those, where French and German polities competed since the death of Charlemagne.

Well, just throwing some ideas.

terryt said...

"We argue that a process of cultural group selection favoring more complex societies may have been important in shaping the present-day global distribution of language diversity".

Although language is quite capable of expanding without corresponding genetic expansion cultural selection may have assisted Y-chromosome and, especially, mtDNA lineages. Children generally learn their mother's language first.

Maju said...

And a third thought on the map: Nigeria clearly has a history of higher political complexity than most or all Middle Africa, yet Middle Africa is much more homogeneous lingusitically. This is because Nigerian states were always small in size, regardless their complexity, while Middle Africa was homogenized lingusitically by the Bantu expansion - not really too "politically complex" in fact.

The same can be said of other tribal expansions of the past, with low level of "political complexity" and sometimes even smashing much more complex polities. Think of Celts, Germanics, Slavs, Arabs and even Turks, for instance. Some highly complex polities just never expanded too much (Sumer for example) while some tribal polities did instead.

The explanation that claims "political complexity" is weak. Political and military power are in fact much better explanations, regardless of "complexity" and sophistication.