Tag Archives: demic expansions

Bring out your dead

490-574

Something major happened to Earth’s atmosphere in 535. We have reports from around the world of the sun being darkened or blotted out for more than a year, and evidence from tree rings and ice cores of an extreme cold spell. The culprit might have been dust thrown into the atmosphere by volcano or a comet. This on its own must have been bad news for the world’s population. But even more consequential was what happened starting seven years later. In 542, bubonic plague made an appearance in the Egyptian port of Pelusium, and rapidly spread around the Mediterranean, eventually reaching much of western Europe and Persia. (China seems to have gotten off more lightly.) It’s possible the epidemic had its origin among rodents in the east African Great Lakes region: disturbances to these populations after 535 may have contributed to the spread of plague, either up the Nile valley, or to trading towns on the Indian Ocean. Recent genetic evidence has confirmed that plague bacteria from this period are almost identical to those from the later, better known Black Death in the late Middle Ages. The plague struck repeatedly around west Eurasia for the next 200 years, before disappearing. The death toll must have been many tens of millions.

Major movements of peoples would follow the plague in the sixth and seventh centuries. The Byzantine reconquest of most of the western Roman Empire, under Justinian, came undone as a new wave of Germanic barbarians, the Lombards, occupied Italy. The Anglo-Saxons expanded from the east of England to occupy most of present-day England. Slavs moved south to occupy most of the Balkans. And, most consequentially, Arabs under the banner of Islam occupied most of the Middle East and North Africa.

Mother-right

Like the traditional poetry of other peoples, the traditional poetry of the Greeks celebrated the Heroic Age. This was the time when men were bigger and stronger, and they performed marvelous feats of prowess. Their weapons were made of bronze and not of iron, and they were ruled by kings. … The Heroic Age came to an end in two great wars – the Theban and the Trojan. … This was how the Mycenaean Greek civilization of the second millennium BC was remembered in historic Greece.

Margalit Finkelberg. Greeks and Pre-Greeks

Classical Greek poetry concerned with the Heroic Age includes a lot of genealogy, with an emphasis on descent in the male line, much like the begats in the Bible. Modern readers familiar with the Iliad and Odyssey find this stuff pretty boring, but it mattered a lot to the Greeks, who would try to link their existing patrilineal clans to the legendary family lines of the Heroic Age.

An emphasis on patrilineal descent is a general feature of early Indo-European society and its later offshoots, including the Greeks; the Indo-European expansion is one phase of the Patriarchal Age, leaving its imprint particularly on the distribution of Y chromosome variants. But given this patrilineal focus, there is something odd about the legends of the Heroic Age. In virtually none of the surviving legends do we find kingship passing from father to son, even when there is a son around. Instead, the normal pattern is that the king’s successor is the guy who marries his daughter – in other words his son-in-law, not his son. Meanwhile, the king’s son has to marry elsewhere. (Although the legends seem to present some cases of rotating succession, where multiple patrilineages took turns marrying into a matrilineage. In these cases, a king’s grandson might marry back into the kingdom, marrying his father’s sister’s daughter.) The implication is that the line of succession to the throne ran from mother to daughter, although it was the husbands of these women who actually exercised power: kingship by marriage. The most notable case of a son succeeding to his father’s throne is the exception that proves the rule: Oedipus got to be king of Thebes because he married Queen Jocasta, not because he was King Laius’ son. (Spoiler alert: see below*)

In Greeks and Pre-Greeks: Aegean Prehistory and Greek Heroic Tradition, Margalit Finkelberg argues that legends of the Heroic Age are memories of a time when the patrilineal traditions of the Greeks coexisted with earlier matrilineal traditions. More specifically, she argues that matrilineal Pre-Greek cultures were associated with the Anatolian language family, the first branch off the Indo-European tree, which also includes Hittite. On her account, Greece looks like ancestral Polynesia, a society flipped from matrilineal to patrilineal by invaders.

Finkelberg is not the first person to notice possible survivals of matrilineal descent from before the coming of the Indo-Europeans and other folk. Such survivals led some nineteenth century scholars to theorize that matrilineality – tracing descent and succession through the female line – was a stage of social evolution that all societies passed through. Some scholars also believed that matrilineal societies were matriarchal – ruled by women. Neither of these theories has held up very well. And yet …

… based on reconstructions of cultural phylogeny and/or ancestral vocabulary a number of the great demic expansions that covered the world seem to have started out matrilineal and/or matrilocal. The list (labeled by associated language families) includes:

So although matrilineal/matrilocal organization is not a stage that every society passes through, it seems to be a phase in many demic expansions. (I wrote an article, The matrilocal tribe: An organization of demic expansion, about this.) This is actually not too surprising. One solid finding in the anthropology of kinship is that matrilocal societies, in which a man goes to live with his wife’s kin when he marries, tend to be internally peaceful, without a lot of feuding between neighboring villages in the same tribe. This makes sense, since the men are no more related to the men in their own village than they are to men in neighboring villages. At the same time, matrilocal societies are often quite war-like with respect to folks outside the larger tribe (just ask the neighbors of the Iroquois or the Navajo). Since matrilocality is associated with internal peace and external aggression, this social organization is well-suited to life along an ethnic frontier. Matrilocality (which is strongly associated with matrilineality) is one way tribal societies generate the social solidarity that enables demic expansion, in a pre-state variant of asabiya.

But there are several limits to matrilocal solidarity. First, the introduction of stock herding tends to undermine matrilocality and matrilineality. (My late colleague Henry Harpending worked with a group, the Herero in southern Africa, who had taken up cattle herding, and were probably in the early stages of transition from matri- to patrilineal.) Also matrilocal/matrilineal societies rarely exceed a few tens of thousands of people. Beyond that size their internal unity tends to break down, and parents start insisting that married sons stick around to defend the homestead. So a lot of the later, better known population expansions, including Indo-European, Semitic, Turkic, and Han Chinese are heavily patrilineal. But even today, traces of earlier matrilineal social organization still survive in some places – in the matrilineal belt of Central Africa, and in some of Southeast Asia, where patrilineality, and mate guarding to secure the male line, mostly don’t reach the same intensity as in much of Asia.

* Oedipus didn’t know it, but Jocasta was his mom.

The world at 1000 BCE

Here’s a quick look at the world around 1000 BCE

The world population is about 50 million.

The Bantu expansion is just beginning, from a homeland on the present Nigeria/Cameroon border. It will eventually cover most of Africa south of the equator. The expansion is sometimes told as a story of first farmers replacing hunter-gatherers. But, as with the Indo-European expansion, this now looks to be too simple. Other farmers and herders reached east Africa before the Bantu; traces of their languages survive as eastern Bantu substrates. So the Bantu had something extra – social organization? malaria resistance? – going for them.

Seafarers with roots in the Lapita culture have already reached Western Polynesian – Samoa and Tonga, previously uninhabited.

The Olmec are flourishing in Meso-America. A controversial find (the Cascajal block) suggests they are just taking up writing.

In China, the Mandate of Heaven has passed from the Shang Dynasty to the Zhou.

In the Near East and Eastern Mediterranean, the Late Bronze Age collapse has opened up space for smaller states. Tyre and other Phoenician city-states are sailing the Mediterranean. Phoenicians are using an alphabet that Greeks will eventually adapt. There might be other borrowings: Odysseus might originally have been Phoenician. At least that was the argument of the early twentieth century French diplomat and classicist Victor Bérard. He thought that Homer had folded an earlier Phoenician picaresque tale into his epic. James Joyce was very taken with this theory; Joyce’s Levantine Leopold Bloom owes something to Bérard’s Phoenician Odysseus.

Further south, Philistines and Israelites have been duking it out, with Israelites gaining the upper hand under David* (king from 1010 to 970 BCE). The Iron Age conventionally begins now, with the widespread use of iron – more abundant and cheaper than bronze.

On the steppe, horses have long been domesticated, but people are now learning to make effective use of cavalry – fighting in formation and firing volleys from horseback. This is the beginning of 2500 years in which the division between Steppe and Sown will be central to Eurasian history.

* Everybody knows that David killed Goliath (1 Samuel 17). However, according to 2 Samuel 21:19, Goliath was killed by Elhanan of Bethlehem. (Depending on which version of the Bible you use, the victim might be given as the brother of Goliath, but the italicised bit is a later interpolation. It’s plain Goliath originally.) Probably the Elhanan story is the original one, and the whole David-and-Goliath story amounts to later resume-padding on the part of David at the expense of a subordinate. See The Historical David: The Real Life of an Invented Hero for this and other demonstrations of how we can recover likely truths from historical texts.

Lapita

lapita

1554-1359 BCE

The Lapita culture (defined based on pottery) starts showing up on the islands of Melanesia around this time. The culture was almost certainly brought from outside, by mariners speaking an Austronesian language (Proto-Oceanic), who traced their roots back (immediately) to island Southeast Asia, and (earlier) to Taiwan. The nearer islands of Melanesia were already inhabited when the Lapitans arrived, by people similar to modern New Guineans, whose ancestors had been there for tens of thousands of years.

The Lapitans had advanced sailing skills, and also introduced some domesticated animals – pigs and chickens. But they don’t seem to have had a huge demographic edge over the earlier inhabitants, who had already developed agriculture on their own, and may have had more resistance to local diseases like malaria. The Lapitans mostly settled smaller, harder-to-reach islands, and established enclaves on larger islands. And one scholar calls the Austronesian expansion “an agricultural revolution that failed” because the pioneers abandoned the rice cultivation that their ancestors had been doing, although they quickly picked up local crops like taro and breadfruit. (In another part of the Austronesian world, island Southeast Asia, they gave up on agriculture altogether to become “fisher-foragers.”)

Curiously, Polynesians today get more than half of their patrilineally transmitted Y-chromosome DNA from Melanesia, while most of their matrilineally transmitted mitochondrial DNA, and even their bilaterally transmitted autosomal DNA, is from Taiwan/Southeast Asia.

There is good reason to think that ancestral Austronesians had a matrilineal social organization, with kin groups emphasizing descent through the female line. This might reflect a history in which men spent lots of time away from home, sailing, raiding, and trading, and chose to leave their households in charge of their sisters. In Micronesia, settled in a separate phase of the Austronesian expansion, matrilineal descent is the rule right up the present – a chief’s heir is his sister’s son, not his wife’s son. Matrilineal societies are often not very intense about policing female sexual behavior (compare the Middle East) and it seemed plausible that when the Lapita folk were passing through Melanesia, the women might have picked up some Melanesian Y chromosomes while their menfolk were off sailing.

But it now looks like the story is different. Ancient DNA from the very earliest Polynesian settlers in Tonga and Vanuatu shows no trace of Melanesian ancestry. Melanesian ancestry apparently came to Polynesia sometime after this initial settlement, perhaps as a result of conquest. And this fits with another aspect of Polynesian kinship: our best reconstructions suggest that Polynesians switched from matrilineal to patrilineal descent early in their history. The recent evidence suggests that a group of Melanesians, arriving later, perhaps as conquerors, may have been responsible for the shift, by setting themselves up as chiefs (in an already rank conscious society) and passing their privileged position on to their sons and their son’s sons – a story already familiar from other parts of the Old World.

A lot of what I know about kinship in Pacific island societies from my late colleague at the University of Utah, Per Hage.

Small tools, and dingoes, and Oz

2213 – 1980 BCE

Australia can seem like the Land That Time Forgot. Australian marsupials were largely isolated from competition with placental mammals from other continents. (Although humans seem to have done in a lot of the megafauna when they arrived.) And many discussions of human prehistory assume that outside contact had little effect on Australia from the time of first settlement, before forty thousand years ago, and the English settlement of 1788. Populations just rose and fell with changes in climate and home-grown innovations in technology.

But there have always been hints that the story was more complicated. Some of the evidence comes from language distributions. The distribution of Australian languages is extremely lopsided. There are a lot of language families in and around the northern peninsula of Arnhemland. Then just one family, Pama-Nyungan, (distantly related to some or all of the others) covers about 80% of the continent.

pama nyungan

This sort of distribution is seen with other language families, where it looks like the signature of population spreads. For example, three of four major branches of the Austronesian language family are found only on Taiwan. The fourth branch, Malayo-Polynesian, spans the world from Madagascar, to island Southeast Asia, to Easter Island. The explanation, supported by many lines of evidence, and almost universally accepted, is that Proto-Austronesian first diverged into separate languages on Taiwan. One bunch of Austronesian speakers then sailed to the Philippines, and thence to farther isles, their languages diverging along the way … and the rest is history (actually prehistory). A similar argument roots the Bantu expansion in the Nigeria-Cameroon border area.

So it looks like there was a similar expansion in Australia. Language change is hard to date, but it’s very hard to believe the expansion happened forty thousand years ago. There is other evidence suggesting a recent date. Some time before 2000 BCE, a new archeological culture, the Small Tool Tradition, swept over Australia. At the same time, natives began exploiting a far wider range of habitats and food sources than previously. And – strikingly – a new animal makes its appearance – the dingo, which must have been introduced from overseas. All of this makes it look like some outside contact, jump-started a continent-scale cultural expansion with new technology, and maybe new forms of social organization.

Just published work on Australian genetics suggests a complicated picture. Northeastern and southwestern Australia, separated by the interior desert, are also strongly genetically differentiated, reflecting a split probably going back sometime between 32 and 10 thousand years ago, i.e. well after initial colonization, but well before the spread of the Small Tool Tradition. But there is also evidence that the last 10 thousand years saw a population expansion in the northeast, a population bottleneck in the southwest, and some gene flow between the two. A scenario that fits the data would be Pama-Nyungan speakers expanding in northeast, and then some northeasterners migrating to the southwest, spreading their language and culture, but not arriving in such large numbers as to replace local populations.

We can expect that the picture will grow clearer as more data accumulate.

“The Aryans”

2993-2719 BCE

For more than two centuries scholars have known that most of the languages of Europe, Iran and Northern India, and assorted other places, are sprung from a common source, from an extinct language, never written down, that came to be dubbed Proto-Indo-European (PIE). It’s been a matter of speculation where and when PIE was spoken. Now, just in the last few years, it looks like the major questions about Indo-European origins are being answered. Research on ancient DNA (check out David Reich’s Who We Are and How We Got Here) has overturned an earlier view (which seemed viable to many researchers even a few years ago) that there were just two major waves of migration into Europe: hunter-gatherers 40 thousand years ago, and farmers from Anatolia starting 7000 years ago. But it turns out that there was also a later massive wave of immigration, coming from the grasslands north of the Black Sea, about 2800 BCE. This migration replaced much of the population of northern Europe, and contributed substantially to southern Europe as well. (See here and here for Logarithmic History blog posts on the possible pre-Indo-European roots of Indo-Europeans.) The migration is a perfect fit for what historical linguists have been saying for a long time. For example, the newcomers brought ox-drawn wagons and wheels with them, matching vocabulary in PIE. (Here’s one of the best books on the subject, by archeologist David Anthony, written even before the latest DNA evidence came in. If you want to delve deeply into the latest DNA news, on Indo-European origins and related topics, here’s a blog for you.)

The intellectual history of the Indo-European question has not just been about pure and objective scholarship; it’s been bound up with the bloody history of the twentieth century.

In 1926, V. Gordon Childe, in his day probably the preeminent prehistoric archeologist in the English-speaking world, wrote a book addressing the topic of Indo-European origins. Synthesizing linguistic and archeological evidence, he named a likely place – the steppes of Ukraine and Southern Russia – and a time – the late Neolithic or Copper age, well after the advent of agriculture, but before the Bronze Age. (The corresponding archeological culture is now called the Yamnaya. However the very earliest split in the IE tree, bringing Hittite ancestors to Anatolia, comes earlier.) He argued that Indo-European speakers had migrated west to conquer big swathes of territory in Europe (Corded Ware and Bell Beaker cultures), and, later, east and south into Iran and India. In other words, he defended what now looks like the correct theory. This wasn’t just a lucky guess. He got it right mostly because he took historical linguistics seriously, as a hard science in its own right.

Childe’s book was entitled “The Aryans: A Study of Indo-European Origins,” and this suggests a problem. Childe acknowledged that the title was a misnomer. Strictly speaking “Aryan” applies only to speakers of Indo-European languages in Iran and India; Childe called PIE speakers “Aryans” simply because it made a better book title. But the title alone was not really the problem. Childe knew that Indo-European prehistory, and the Aryan label, were popular with the nationalist German Right. Childe had no sympathy for German nationalism. He was an Australian who lived most of his life in England. He was also a lifelong socialist and a man of the Left. In fact his book aimed at deflating nationalist claims. He located the Indo-European homeland in Eastern Europe, not Germany or Scandinavia, as some claimed. And he denied that the “Aryans” had any special racial genius. He did think that Indo-European languages (not a racial character) were “exceptionally delicate and flexible instruments of thought” that facilitated later intellectual developments. (This one probably won’t fly. Linguists nowadays mostly don’t think grammar has that much effect on cognition.) And he speculated that “Aryans” might have had an advantage over other folk simply by virtue of being large and well-fed. (This one isn’t totally crazy. Indo-Europeans were apparently big guys, like the Nilotic cattle herders of East Africa to whom they show some interesting convergent cultural similarities.) Nonetheless, the whole subject grew increasingly uncomfortable as the 1920s moved into the 30s. Childe let the book go out of print, and scarcely referred to it in the course of a long productive career.

Beyond killing tens of millions of people, Nazism also had a long lasting deforming effect on intellectual life. For most of the later twentieth century Anglo-American archeologists went out of their way to avoid topics like migration, barbarian invasions, and population replacements. These were, in today’s jargon, problematic. For example, it was clear that something dramatic happened over a huge stretch of Europe, from Poland to the Netherlands, in the early third millennium BCE: settled life gave way to nomadism, farming to cattle raising. But this was written off as a technological shift, the Secondary Products Revolution. (To be fair, there were some exceptions among archeologists, like David Anthony and Marija Gimbutas, and many exceptions among linguists. Jared Diamond also got it right.) In some ways, then, we’re just beginning to recover, intellectually, from the Second World War.

First farmers

8.80 – 8.32 thousand years ago

Farming is now spreading out of the Fertile Crescent. Farmers have crossed the Aegean, and appear in the Balkans and Greece. (They got to Cyprus more than a thousand years earlier.) Farmers have also begun spreading out of the Yellow River and Yangzi River valleys in China.

There’s an argument among philosophers of a utilitarian bent, started by Derek Parfit, over which is better: a world with just a few very happy people (more happiness per capita), or a world crowded with a multitude of people for whom life is just barely worth living (more total happiness)? The choice of the latter has been dubbed the “Repugnant Conclusion.” Whatever the philosophical merits of one possible world or another, there’s little doubt about which direction social evolution usually takes. “God favors the side with the largest battalions” (a saying often attributed to Napoleon, but actually predating him), and agricultural populations have mostly managed to replace hunter-gatherers, even though they are probably worse fed and sicker on average. The DNA evidence shows that in Europe it’s mostly replacement we’re talking about, not just the spread of new technologies. Migrants originally from Anatolia pushed aside indigenous hunter-gatherers without much interbreeding. In Western Europe the replacement wasn’t entirely peaceful. In the north, in what is now Germany and the Low Countries, farmers from the intrusive Linear Pottery (LBK) culture built fortified settlements, and there was an unpopulated no-man’s land between farmer and hunter-gatherer territory. Along the Mediterranean shore, farmers from the intruding Cardial (Impressed Ware) culture sometimes killed foragers, and kept their heads as trophies.

For a while, a decade ago, it looked as if the spread of agriculture might also explain much of the distribution the world’s major language families. Peter Bellwood’s book First Farmers made this case. According to this theory, the first farmers in Europe were speakers of an early Indo-European language that eventually gave rise to most of the languages of Europe, as well as Iran and northern India. We’ll see in days to come on Logarithmic History that the story turns out to be more complicated.