Genes, Peoples and Languages

PENGUIN BOOKS

GENES, PEOPLES AND LANGUAGES

'There may be no contemporary scholar who ha's a more detailed understanding of human diversity or a more compelling vision of its 'unified history ... This project is an immense intellectual achievement, and Genes, Peoples and Languages is a fine way to get a sense of its scope' Edward Rothstein, The New Y01-k Tirnes ith the exterior, missionaries, for instance, and have radios and schools_

C, r i t i c a l ( R e c e p t i v e/S u s c e p t i b l e ) P e r i o d s a n d T h e i r I m p o r t a n c e

Most culturally determined characteristics are more easily changed than genetic ones. Even for clear-cut genetic diseases, onset can occur very late in life, with much variation from one individual to another. Huntington's chorea can strike individuals ranging from

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two to eighty years old, although most cases . manifest themselves around the age of forty. But the pattern of inheritance is very strict.

Some genetic diseases disappear with age, as do certain types of allergy. But in general, genetically determined characteristics are rather stable and rarely reversible. The same is not true of cultural characteristics. We have already observed that religiOUS conver­ sions take place. Political affiliations also change with appreciable frequency. Nevertheless, some cultural traits change less readily than oth­ ers. Stability of celiaili behaviors may be favored by biological fac­ tors that render changes more or less likely at celiain ages. In other words, there may be sensitive or clitical periods in life, the phe­ nomenon sometimes called "imprinting." The most obvious critical period, although inadequately stud­ ied, is undoubtedly the one governing our ability to learn a first and a second language. The first language must be acqUired in the first years of life. One can learn other languages after the first, but rarely, if ever, as well; it is particularly difficult to learn proper pro­ nunciation of a foreign language after puberty. The time before puberty is- also a sensitive period for acquiring the incest taboo. The psycholOgist Edward Westermarck has sug­ gested that the cohabitation of brothers and sisters before puberty could diminish sexual interest and explain . why incest between brothers and sisters is as rare for humans as it is for other mammals. There have been notable exceptions in some ancient dynasties such as those in Egypt and Persia, where the maniage of Siblings was encouraged, but this custom quickly- disappeared. In some commu­ nities, especially in the Middle East and India, marriages between close relatives (e.g., uncle and niece, first cousins) are still frequent, but this is a different phenomenon. Westermarck's hypothesiS was tested by Arthur Wolf

( 1980)

in

Taiwan, where marriages have occurred between a boy and an adopted sister of similar age. The daughter would be adopted by the boy's parents after his birth. In a society where spouses are bought, adoption at a very young age guaranteed a lower buying price. This custom also afforded the mother the opportunity to

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instruct the future daughter-in-law in the ali of serving he.r hus­ band. Wolf showed that these marriages were less successful than others; they ended more often in divorce and produced fewer chil­ dren on average. This result is consistent with data from Israeli kib­ butzim where children are raised together in a SOlt of com�unal nursery, and have little contact with their parents. These children essentially have a very large family of adoptive brothers and sisters, and very few marriages occur between children from tlle same kib­ butz. It is harder to fall in love with someone whom you are used to seeing on the potty. There are celtainly many other clitical peliods in the fonnation of human societies, about which we don't cunentIy 1000W much. Even those tIlat I've just cited have not been studied in sufficient detail. I could mention just two other areas deserving further inquiry. Gianna Zei, Paola Astolfi, and Suresh Jayakar have shown that daughters of an older father tend to many men considerably older tllan tIlem­ selves. This may be pali of a more general phenomenon, which deserves to be investigated in great detail: it is likely that we have a tendency to choose spouses who share some physical resemblance (and perhaps behavior) with our opposite-sex parents. This phenom­ enon could explain the pronounced physical resemblance obselved among individuals of the same social group-especially obvious in tile small and isolated ones. The same phenomenon broadens differ­ ences between groups. In another investigation aided by psychologists, we studied the propensity of our Stanford students to identify witIl a pi.uticular region or physical habitat. Our preference for mountains, plains, seashores, lakes, big cities, or small towns is probably set at an early age. I became interested in this when I realized that I had no padic­ ular preference. The desert, countrySide, or city were all tile same to me, so long as the humidity was not too high. I thought this might be due to my parents' frequent changes of residence before I was four years old. In America the importance- of the environment in which one lives can be seen in the frequency with which immi­ grants establish themselves in areas that resemble those they have left. Our studies of Stanford students confirmed that those who

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moved frequently during childhood had trouble identifying with a particular environment and adapted more easily to all environments. Our data did not allow ,,:!S to determine the most sensitive age, but the study did succeed in showing that a nomadic tendency can be culturally inherited, and that a psycholOgical imprint received while young is difficult to erase later in life. Governments or countries with large nomadic populations (e.g., Gypsies, Bedouins, Berbers, Tuaregs, Pygmies) have difficulty changing their nomadic habits. This poses serious problems for the schooling of their children. Moreover, the freedom of nomadism is fascinating, and if that is the way in which one was raised, it must be very difficult to settle down.

L i n g u i s t i c Evo l ut i o n as a n Exa m p l e o f C u lt u r a l Evo l u t i o n

Amazingly, linguistic evolution has not been studied much. There is great potential for rigorous quantitative analysis, and research is not very expensive. Interest in language evolution began in the second half of the nineteenth century, by applying the methods of evolution­ ary trees to the history of language differentiation--especially the Indo-European languages. I have already mentioned that August Schleicher constructed a tree of this family th�t resembled one based on a recent study. Even though the phenomenon of borrOwing words from other languages, espeCially from neighbors, is well established,

the most studied evolutionary trees give the impression that a lan­

guage changes in ways that are largely independent of changes taking

place in other languages. This is a prerequisite for the applicability of

tree analysis. We lrnow that languages are often spread over large areas with different varieties (or dialects) developing locally. We are aware that a language changes slightly even within an individual life­ time, but lrnowledge of old languages is limited, making variation in time somewhat less easy to study than variation in space. Neverthe­ less, variation in time almost automatically implies variation in space, and the basic rules are the same for both.

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What precisely is linguistic variation? There are several aspects. Phonological variation is easily perceived. In any European country, and even in the United States, significant differences in accent occur between north and south, east and west. With a little experience, we can easily guess someone's native region. The pronunciation of words changes in time and space-----often significantly. Another aspect of ph?nological variation is the richness or poverty of sounds in different languages. Polynesian languages have among the fewest sounds. They have only three vowels: a, i, and u. English is at the opposite extreme with twenty or so vowel sounds (including diphthongs), which are different from those found in all other languages, making the acquisition of English very difficult for foreigners. The speed with which vowel sounds change is particu­ larly astonishing. To paraphrase Voltaire: if the consonants are not very useful for etymological reconstruction, the vowels are com­ pletely useless. Semantic variation is the change of word meanings. For exam­ ple, the French word femme has acquired a second meaning, to include both "woman" and "wife." In Italian, the word donna (origi­ nally derived from the Latin word domina meaning "household mas­ ter") means "woman," but Italians use moglie (from another Latin

mulier) for "wife." Italian also uses femmina (from the same root asfemme in French) to mean only "woman" and not "wife."

word,

Although grammar is the most stable part of a language, it too can change with time. In English, as in French and Italian, the nor­ mal word order in a sentence is subject (S), verb (V), and object (O)-or SVO. But all eight possible word orders exist in various lan­ guages, even if SVO and SOy languages are much more common. The rarest are OVS and Osv. In the film

Return of the Jedi,

Yoda,

the master of the Jedi, uses the OSV style: "Your father he is." For each of these three modes of linguistic variation (phonologi­ cal, semantic, and grammatical), change in space is more obvious and easier to study than change in time. We can illustrate on a geographic map the variation a word experiences by drawing a curve delimiting the areas where the word has a particular pronunciation. This curve,

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which separates one homogeneous region from another, is called an C