July 31, 2012

Redating of Later Stone Age brings it in line with Upper Paleolithic

Two new papers in PNAS document that the Later Stone Age (LSA), the period of African prehistory corresponding to the Upper Paleolithic in Europe, began earlier than previously thought (c. 44ka BP), and contained elements of the material culture of present-day San populations.

There really seems to have been a Big Bang of sorts during that time that has now been shown to have affected most of the world: early modern humans in Europe were replacing Neandertals and starting the Aurignacian, fishing in the open seas in East Timor, and, now it seems, hunting and living in a very modern way in South Africa.

Intriguingly, the evidence for archaic admixture in Africa (Lachance et al. 2012; Hammer et al. 2011) point to about the same time. And, the 37,000 year old Hofmeyr skull from South Africa is most similar to early Upper Paleolithic European specimens. Together with new evidence about the human Y-chromosome phylogeny, it seems inescapable that something very big was taking place all over the world around the same time, something quite akin to the spread of a new people and not only to a spread of a new technology or way of thinking.

While precursors to modern human behavior have been documented in earlier contexts in Southern Africa and even among European Neandertals, these pale in comparison to the MP/MSA to UP/LSA transition. Here, we have near-simultaneous appearance of fully modern human behavior all over the planet, the appearance of fully modern skull forms with unmistakeable long range links, the rooting of most major Y-chromosome haplogroups, evidence for archaic admixture/disappearance. It was a real quantum leap in both human creativity and in the spread of human physical presence around the globe.

I have previously expressed the opinon that the "trigger" for this remarkable phenomenon can be found a few thousand years earlier, when the Sahara-Arabia belt entered a dry phase that would have driven its population outwards. But, really, the near simultaneous appearance of the same phenomenon all over the planet makes it difficult to find its ultimate source. These are exciting times for human origins research!

Press releases: Later Stone Age got earlier start in South Africa than thoughtModern culture 44,000 years ago
Coverage elsewhere: NY Times.

UPDATE I: From d' Errico et al.:
Contrary to lithic technology, which shows at Border Cave agradual evolution toward the ELSA starting after 56 ka (21), organic artifacts unambiguously reminiscent of LSA and San materialculture emerge relatively abruptly, highlighting an apparent mismatch in rates of cultural change. Our results support the view that what we perceive today as modern behavior is the resultof nonlinear trajectories that may be better understood whendocumented at a regional scale (7, 12–14, 21, 54).
Villa et al. also have a section on whether or not the MSA persisted longer than the arrival of the LSA:

Did MSA Technology Survive Until 26–20 ka in South Africa? Several sites in South Africa Lesotho and Swaziland are dated to the interval between 40 and 20 ka and defined as MSA or transitional MSA–LSA (11–15, 63). However, many assemblages have uncertain stratigraphy or small and undiagnostic inventories or are poorly dated or unpublished. A few have only preliminary descriptions. 
At Rose Cottage three layers (DY, DC, and RU) dated between ca. 30.8 and 27 ka are defined as final MSA (64). They are described as having bladelets produced by the bipolar technique but also having “MSA” types of formal tools (11). 
Strathalan Cave B (Eastern Cape) has two main layers dated between 29 and 25.7 ka. Their inventory, defined as late MSA, includes single and multiplatform cores, some blades, many irregular flakes, and very few retouched blades and flakes (65). At Boomplas Cave (Western Cape) the uppermost MSA level (BP), dated to 34–32 BP, is unpublished. Layer LPC contains an assemblage classified as LSA, with two bone points and few bladelets, dated to ca. 21 ka (2, 14). Systematic technological analyses and more dates are needed to break the impasse (63). 
It does seem that part of the reason why the MSA/LSA transition was dated later was that it did not happen simultaneously overnight. There is also very good reason to think that if the simultaneous appearance of modern behavior around the world was related to the spread of modern humans, then the modern San are not simple direct descendants of the Border Cave population, since their divergence from Eurasians greatly exceeds 100,000 years. A simpler explanation might be that at 44kya there was a migration of behaviorally modern people (evidenced e.g., by links between Hofmeyr and Eurasians), but that in Africa this set of people admixed with more divergent African populations; there is evidence of deep links between South and East Africans, as well as of more recent links between South  and West African farmers and East African pastoralists. Clearly, things were going on in the region in the last 40,000 years, as they seem to have done elsewhere.


PNAS doi: 10.1073/pnas.1202629109

Border Cave and the beginning of the Later Stone Age in South Africa

Paola Villa et al.

The transition from the Middle Stone Age (MSA) to the Later Stone Age (LSA) in South Africa was not associated with the appearance of anatomically modern humans and the extinction of Neandertals, as in the Middle to Upper Paleolithic transition in Western Europe. It has therefore attracted less attention, yet it provides insights into patterns of technological evolution not associated with a new hominin. Data from Border Cave (KwaZulu-Natal) show a strong pattern of technological change at approximately 44–42 ka cal BP, marked by adoption of techniques and materials that were present but scarcely used in the previous MSA, and some novelties. The agent of change was neither a revolution nor the advent of a new species of human. Although most evident in personal ornaments and symbolic markings, the change from one way of living to another was not restricted to aesthetics. Our analysis shows that: (i) at Border Cave two assemblages, dated to 45–49 and >49 ka, show a gradual abandonment of the technology and tool types of the post-Howiesons Poort period and can be considered transitional industries; (ii) the 44–42 ka cal BP assemblages are based on an expedient technology dominated by bipolar knapping, with microliths hafted with pitch from Podocarpus bark, worked suid tusks, ostrich eggshell beads, bone arrowheads, engraved bones, bored stones, and digging sticks; (iii) these assemblages mark the beginning of the LSA in South Africa; (iv) the LSA emerged by internal evolution; and (v) the process of change began sometime after 56 ka.

Link

PNAS doi: 10.1073/pnas.1204213109

Early evidence of San material culture represented by organic artifacts from Border Cave, South Africa

Francesco d’Errico et al.

Recent archaeological discoveries have revealed that pigment use, beads, engravings, and sophisticated stone and bone tools were already present in southern Africa 75,000 y ago. Many of these artifacts disappeared by 60,000 y ago, suggesting that modern behavior appeared in the past and was subsequently lost before becoming firmly established. Most archaeologists think that San hunter–gatherer cultural adaptation emerged 20,000 y ago. However, reanalysis of organic artifacts from Border Cave, South Africa, shows that the Early Later Stone Age inhabitants of this cave used notched bones for notational purposes, wooden digging sticks, bone awls, and bone points similar to those used by San as arrowheads. A point is decorated with a spiral groove filled with red ochre, which closely parallels similar marks that San make to identify their arrowheads when hunting. A mixture of beeswax, Euphorbia resin, and possibly egg, wrapped in vegetal fibers, dated to ~40,000 BP, may have been used for hafting. Ornaments include marine shell beads and ostrich eggshell beads, directly dated to ~42,000 BP. A digging stick, dated to ~39,000 BP, is made of Flueggea virosa. A wooden poison applicator, dated to ~24,000 BP, retains residues with ricinoleic acid, derived from poisonous castor beans. Reappraisal of radiocarbon age estimates through Bayesian modeling, and the identification of key elements of San material culture at Border Cave, places the emergence of modern hunter–gatherer adaptation, as we know it, to ~44,000 y ago.

Link

33 comments:

Lank said...

Together with new evidence about the human Y-chromosome phylogeny, it seems inescapable that something very big was taking place all over the world around the same time, something quite akin to the spread of a new people and not only to a spread of a new technology or way of thinking.

No Y-DNA or mtDNA lineages dated to 40-50 kya indicate a connection between the ancestral Khoisan and Eurasians. Within Eurasia, Y-DNA CF does fit the time frame. But I don't see an African connection, unless we go back to Out of Africa.

Baldric said...

Lank, the variation autosomes does not have to travel attacked to an Y-DNA lineage. And if it was completely necessary... this "out of Arabia" model brings up an ocean of new possibilities. What if haplogroup E had really originated in Asia? in Arabia?

terryt said...

"No Y-DNA or mtDNA lineages dated to 40-50 kya indicate a connection between the ancestral Khoisan and Eurasians".

The paper actually claims, '(v) the process of change began sometime after 56 ka'. So not quite true if we accept the dates Dienekes gets in his previous post. E1 and E2 split at 57,703 years ago. Although on the face of it that looks perhaps a little early to be involved with the Khoisan maybe the haplogroup didn't reach them for a couple of thousand years.

"Together with new evidence about the human Y-chromosome phylogeny, it seems inescapable that something very big was taking place all over the world around the same time, something quite akin to the spread of a new people and not only to a spread of a new technology or way of thinking".

But:

"ii) the 44–42 ka cal BP assemblages are based on an expedient technology dominated by bipolar knapping, with microliths hafted with pitch from Podocarpus bark, worked suid tusks, ostrich eggshell beads, bone arrowheads, engraved bones, bored stones, and digging sticks"

And:

"reanalysis of organic artifacts from Border Cave, South Africa, shows that the Early Later Stone Age inhabitants of this cave used notched bones for notational purposes, wooden digging sticks, bone awls, and bone points similar to those used by San as arrowheads. A point is decorated with a spiral groove filled with red ochre, which closely parallels similar marks that San make to identify their arrowheads when hunting. A mixture of beeswax, Euphorbia resin, and possibly egg, wrapped in vegetal fibers, dated to ~40,000 BP, may have been used for hafting".

All these technologies are associated with men and would most likely have been passed from father to son, or uncle to nephew. That would explain the sudden Y-DNA expansion.

"(i) at Border Cave two assemblages, dated to 45–49 and >49 ka, show a gradual abandonment of the technology and tool types of the post-Howiesons Poort period and can be considered transitional industries"

And:

"(iv) the LSA emerged by internal evolution"

The fact they are 'transitional industries' would explain the survival of A and B haplgroups.

Teo. said...

Sorry to "intervene", but I see there is an issue that many people tend to neglect in these discussions (both in this and the previous post). As a linguist (well, an aspiring one, at least) I’m perhaps biased to think that some of these numbers are always just way TOO OLD. There are just too few recognizable language families, particularly in Africa and West Asia, for, say, 100kya or even 56kya to make sense, considering the low diversity there.

I mean, even if we split Niger-Congo/Nilo-Saharan and include the isolates we know went extinct in those areas, the numbers don’t fit! Other traditional areas had a lot more diversity before contact, and even after massive reduction in diversity are still several orders of magnitude more diverse than Africa (or West Asia).

And it isn’t just in the linguistic phylogeny, synchronic characteristics too. Even "Khoisan" languages, apart from their phonetics, are boringly uneventful in their linguistic typology.

Clicks are the only really “peculiar” thing there – but then, every other language family/area similarly has one odd “peculiar” thing that stands out. And the Pygmy languages are, currently at least, all “Niger-Congo”, with no obvious substrate. These two groups of languages don’t look too detached from the others at all, and certainly not “archaic” in any sense.

Given all that, there is something very, very strange going on here. Apparently, we are left with 4 possibilities:

a) There has been massive language replacement in most of the world and particularly Africa and West Asia, in a scale more massive and more complete than anything we have witnessed in recorded history (but then WHAT would have caused something that not even modern warfare and long-range spread of diseases could cause ?).

b) Africa and West Asia are the wrong places to look for the origin of modern humans.

c) The place is right, but the older estimates are wrong: our immediate ancestors came later.

Or

d) The numbers are right and the place is right, but language came later as a cultural toolkit and spread (clearly unevenly) throughout the world, maybe post-40kya. Some linguists would dismiss this based on the standard Chomskyan assumptions, but, if the other hypotheses fail, we may have to face this possibility.

bmdriver said...

Origin of modern humans?..the one place everyone tries to avoid....South Asia.

Slumbery said...

Teo

I think the diversity of the languages in an area is more connected to isolation than to how old are the human settlement there.

I show you a modern example: Caucasus vs. Southern part of the Middle East. Based on any origin theory that is in the game, the latter is inhabited by modern humans for a longer time, yet the language diversity is higher in the Caucasus. Because it is more isolated.

The effect of (long term) isolation surely played a strong role in the development of high language diversity in ancient times too.

Also, when we talk about events 40 kY BP or so long time ago, linguistic becomes increasingly a fantasy genre.

Lank said...

Y-DNA E1b1 has nothing to do with the ancestral Khoisan population. The E lineages they carry are all related to recent admixture. E-M2 and E-M75 came with Bantu admixture, and E-M293 with the pastoralist East Africans. It's a bit dubious to try to connect the LSA people living in southern Africa 44 kya to Y-DNA E populations, when their only technological/cultural connections lie with the Khoisan.

It all seems to fall back on the assumption that the LSA is of Eurasian origin, for which there is no evidence, and the resulting conclusion is that E or DE must then be of Eurasian origin. Sure, Hofmeyr apparently resembles Europeans, but there is no indication that this is a result of a migration into Africa. On the other hand, there are genetic signs of an Out of Africa migration that predates the LSA Border Cave findings by less than 20,000 years.

If anything, assuming Dienekes' Y chromosome age estimates are accurate, Y-DNA CF would be the best candidate for a Eurasian Upper Paleolithic marker. DE would either represent an Out of Africa remnant, or a very early back migration. But I don't know if the latter scenario makes much of a difference, considering its age (DE is very close in age to CT, and somewhat close to BT, and closer to either of them than to CF).

Teo. said...

@Slumbery

Yes, I know macro historical linguistics does raise some eyebrows, but it will have to be done, eventually. We may not have the ideal methods in place, but it doesn't prevent us from provisionally extrapolating from the tried and true methodology of traditional historical linguistics – you know, of the sort that brought us PIE and without which nobody here would be having any discussions about linguistic groups.

On the issue of diversity/origin, it doesn't always work that way, and there are some notable exceptions, but it generally does work, and so it is a sound working hypothesis.

But, now, let's assume for a moment that you are right about the isolation/diversity ratio: it would require the San area to be EXTREMELY NON-isolated in comparison with Eurasia! The problem is, we have no reason whatsoever to assume that, quite the contrary.

Besides, if we're forced to accept that the San carried on a technological tradition dating from before 30kya, then, it becomes almost imperative to presume that they had been ISOLATED to some extent for a long time – and yet their languages don't seem to reflect that at all, either in phylogeny or in features.

Not only that, sub-Saharan Africa as a whole is extremely undiverse and there doesn't seem to be any good reason for that. Just compare it with New Guinea, which supposedly was populated long after Africa: NG was certainly not that isolated, either, having had contacts with groups from east Asia and Australia. And yet, NG is immensely more diverse than Africa. In a small stretch of land running the northern half of the island alone you can find more language families and isolates than in the whole of Africa (even accounting for further splits there). Has SS Africa been such a hotbed of cross-contact in comparison with NG – or much of Eurasia, for that matter? I don't think so.

So, again, either there was a “mass language extinction” event on a scale never seen again, or there is something very strange here. The linguistic assumptions may be wrong, the genetic assumptions may be wrong, or both. The four hypotheses I mentioned earlier.

German Dziebel said...

@Teo

I completely agree with your reasoning. Africa must have been colonized by behaviorally modern humans around 40,000K to explain its low linguistic diversity (20 stocks in the revised version of the African language classification) compared to PNG, the New World and parts of Asia.

Since they admixed with some local hominin populations (mislabeled as "anatomically modern humans") who lacked our symbolic capacities, they ended up carrying some divergent genetic lineages. It's possible that Y-DNA A and mtDNA L0 are precisely these archaic introgressions.

Slumbery said...

@Teo

1. I am not sure that Sub-Saharan Africa was colonized much earlier that New Guinea.

2. I am a bit confused, because linguistic articles (admittedly "for the public" types) I read earlier stated that the Sub-Saharan languages are very diverse. Now you just say it is actually the opposite. I have no time and resource to double check this.

Teo. said...

@Slumbery

What you've read, probably, is that Africa has a largish number of languages. That is true. However, the number of phyla is very small. As German said, the maximum is 20, and even that requires a radical “splitter” view.

15 or 20, when we look at the size of the continent and the presumed antiquity of human occupation there, is an exceedingly small number. What's more, the linguistic diversity among the supposedly most divergent human groups is even smaller than the overall diversity of the continent. It's all very odd. And this is a severely underrated problem.

That is not to say Africa or its neighbouring areas can't be at the root of human dispersals. They can be, and so far appear to have been. But we need an explanation for the above situation.

The biggest problem is, very few people appreciate the issue (IIRC, I've seen it occasionally discussed in this blog, though). On the top of my mind, I remember just two or three major papers on this topic, and their solutions didn't seem very convincing.

Clay said...

I enjoy the discussion of linguistics. However,it seems to me the larger question is whether this change in technology and behavior as revealed in the record is the result of cultural changes or genetic/biological changes. Is this great leap forward the result of the expansion of a small population with new skills or something that happened everywhere as a result of other pressures (like climactic change or intensification of populations)?

It seems that the comments here lean toward an expansion of a small, behaviorally modern population. But it seems to me the most parsimonious explanation is the other one. Didn't native Australians and other similarly isolated groups display modern behavior, like abstract artwork left on stone surfaces, before admixture of populations is credible? Isn't the most conservative explanation that we all behave in the same way and have the same capabilties because we inherited the same "software" from a common group of ancestors?

Dienekes said...

Geology and climate have thrown challenges at humans many times; but apparently humans did not adapt in the way they did in the UP/LSA when that happened.

Also, if different groups of humans independently adapted to some big shock (what would that be?) during this transition, then we would not see the proliferation of modern skull forms and the coalescence of Y-chromosome lineages on a global scale. Rather, we would see a transformation of regional populations (e.g., Neandertals in Europe) in response to the new challenge.

Belenos said...

@Teo

There are no Pygmy languages, but there is strong evidence for a shared substrata of unknown origin, relating to forest specific vocabulary.

Solís said...

http://www.sciencenews.org/view/generic/id/342701/title/Sticks%2c_stones_and_bones_reveal_emergence_of_a_hunter-gatherer_culture

Onur said...

Most of Sub-Saharan Africa was ethnically cleansed during the Bantu expansion by the migrating Bantus. The non-Bantu parts of SS Africa too show strong signs of recent population and language expansions. Pre-Neolithic SS Africa must have been immensely more ethnically and linguistically diverse than today's SS Africa. Same for Europe and West Asia.

terryt said...

"Is this great leap forward the result of the expansion of a small population with new skills or something that happened everywhere as a result of other pressures (like climactic change or intensification of populations)? It seems that the comments here lean toward an expansion of a small, behaviorally modern population".

Some sort of combination of the two is not impossible, and I think likely to be the explanation. The haplogroups were carried originally by a small population with new skills but the expanding population mixed with the local inhabitants as they expanded.

Teo. said...

@Belenos
That idea is still controversial, and views differ wildly. Although we could expect such a substrate, the evidence I've seen so far is not very clear. But maybe you know things that I don't. I'm certainly no expert in Niger-Congo.

@Onur
Obviously the Bantu expansion must have wreaked linguistic havoc (just like the neolithic expansions in Europe and SE Asia), but it still doesn't explain the scale of what happened. If human presence in SS Africa was so old, we'd expect the pre-Bantu diversity to be huge everywhere (certainly much higher than, say, New-Guinean levels or South American levels) and that even with a major replacement event like the Bantu expansion there would be some hint of the former diversity left.

However, with a few exceptions, there is no trace of that. Either it wasn't there in the first place, or the changes caused by the Bantu expansion in Africa must have been something so catastrophic that nothing of that scale is visible anywhere else.

And btw the European case is different, because that is not where the deepest genetic clades are, or where the alleged most divergent populations are. It is not supposed to have been as diverse as Africa in the first place, if the “mainstream” assumptions are/were right.

Also, not all major agricultural expansions necessarily wiped out indigenous languages/populations. In New Guinea, for example, there have been many such expansions (the main ones associated with Trans-New-Guinea and Austronesian), and yet most of the diversity is still there. Huge diversity! So the question is: what the heck happened with the languages of Africa? Or perhaps nothing happened and our assumptions are wrong?

Belenos said...

@Teo

The substrata of several pygmy languages is debated, but not in terms of whether it exists, as to whether it is Pygmy or the survival of another non-pygmy isolate. But it must be recognised that the substrata is very limited in extent, not covering even a 5th of pygmy range.

But pygmies by no means exclusively speak Niger-Congo, various groups speak central Sudanic. And those that do speak Niger-Congo speak dialects from different branches of that family, depending who their neighbours are.

All this evidence points to language replacement following the migration of larger statured populations, especially the Niger-Congo expansion.

Onur said...

However, with a few exceptions, there is no trace of that. Either it wasn't there in the first place, or the changes caused by the Bantu expansion in Africa must have been something so catastrophic that nothing of that scale is visible anywhere else.

The impact of the Bantu expansion was catastrophic in the regions it occurred. It not only almost totally wiped out the pre-Bantu languages of those regions but also almost totally wiped out the pre-Bantu peoples there with their genes. The Bantu expansion was not the only recent language expansion in Africa, as the other Niger-Congo branches, the Nilo-Saharan language family and the Afro-Asiatic language family also expanded in Africa during the Neolithic and the following periods. As a result, today's Africa is linguistically immensely less diverse than pre-Neolithic Africa.

Teo. said...

@Belenos

Thanks. Of course, even if they did speak other, pre-contact languages, that doesn't mean these had to be fundamentally different from Niger-Congo or Nilo-Saharan. If they were already related to begin with, btw, that would explain why finding an exotic substrate appears to be so hard. But we really have no hard evidence either way, and their languages may indeed have been very diverse and then were wiped out (but see my reply to Onur below).


@Onur

I don't deny that is possible at all. That is apparently what happened. But then we need an explanation. Again, the question faced by linguists and anthropologists is, why was this replacement so much more severe in SS Africa? Because this was no trivial language replacement.

Other areas that experienced similar traumatic effects during post-neolithic expansions did preserve a lot more linguistic diversity. The Americas suffered one such catastrophe, with the aggravated circumstances of modern warfare and disease, and yet even today in, e.g., Peru alone there are way more linguistic phyla than in the whole of Africa.

To sum up the issue, at the risk of becoming repetitive: why SS Africa, of all places, an area which, given certain assumptions at least, was supposed to harbour more linguistic diversity than everywhere else during pre-neolithic times, is precisely where diversity appears to have been most ruthlessly culled?

Onur said...

To sum up the issue, at the risk of becoming repetitive: why SS Africa, of all places, an area which, given certain assumptions at least, was supposed to harbour more linguistic diversity than everywhere else during pre-neolithic times, is precisely where diversity appears to have been most ruthlessly culled?

Africa is not alone in losing most of its linguistic diversity beginning from the Neolithic revolution: Eurasia too lost most of its linguistic diversity beginning from the Neolithic revolution. In fact, the Americas and New Guinea are unique in remaining linguistically diverse even after the Neolithic.

Slumbery said...

Teo.

I still keep my opinion that New Guinea is an extremity and mainly because of isolation. You say there were migrations too, but the Austronesian migration did not wash trough the mainland New Guinea. Combine this with the archaic human admixture results (Denisovan admixture remained intact only here) and you have to deal with possibility that the human population was mostly continuous and berely disturbed here in the last 40kY or so. So far you can't say the same about any part of Africa.

At the other hand Peruvian language diversity proves more my point that yours in a sense. We know that Peru was populated less than 20kY ago. If this time was enough for such a diversity to rise then other diverse regions does not need to be especially ancient either.
This is one of the reasons why I said that 40k+ Y is too much time for linguistic.

Teo. said...

“This is one of the reasons why I said that 40k+ Y is too much time [to explain linguistic diversity]”

And I agree with you on this, Belenos. But that is not the standard assumption of many anthropologists and linguists. I was only saying that, under those assumptions, we'll have a lot of trouble explaining linguistic diversity. Something is not right.

As for the New Guinea example, yes, Austronesian was literally a ripple on the water, although even in the coastal areas reached by it it did not lead to the extinction of most phyla. Even at the supposed cradle of Proto-Oceanic there are Papuan languages to this day. But anyway, the real test is Trans-New-Guinea, which is associated with a sweeping agricultural expansion throughout the region that nevertheless left behind a lot of linguistic diversity.



“Africa is not alone in losing most of its linguistic diversity beginning from the Neolithic revolution: Eurasia too lost most of its linguistic diversity”

Onur, again, that is ok. But there are two problems:

a) Eurasia had multiple neolithic “bursts” and the resulting crops and herds are easily adaptable from one end of the continent to the other under most climatic conditions, so a general “wipe-out” and a series of sweeping expansions (IE, Turkic, Sinnitc etc.) are not unexpected. I'm not sure the same is true of SS Africa. Even if there were pre-Bantu expansions, they don't seem to have been as numerous or as successful as the multiple Eurasian ones.
But, even if that “wipe-out” scenario is possible, there is another problem:

b) Again, if language as we know it was an early phenomenon, the diversity in Africa was supposed to be much much higher than elsewhere pre-Neolithic, so that even a wipe-out should leave at least some hint of that former diversity intact in isolated pockets. We see very little of that. Why did the “linguistic culling” have to be so complete?

The Eurasian situation is supposed to be an already smaller diversity reduced to very little after countless Neol. Expansions for a long time, whereas the African one is supposed to be huge diversity reduced to very little after a handful of expansions (certainly fewer than Eurasia, and beginning later). Why? That is what is unique and requires explanation.

Teo. said...

@Belenos

Sorry, I read your reply again and in the first part of my latest post I believe I misinterpreted your point. You were talking about linguistic methods, I was talking about data on linguistic diversity. My opinion on the issue I mention is the same, though.

Teo. said...

Oh my! And on top of the previous slip, I realise now I mistook Slumbery for Belenos in my reply. Sorry to both. I think that just means I need some sleep - and some time off this debate for a while heheh.

Onur said...

Teo,

Why do you assume linguistic diversity always increases in pre-Neolithic contexts? By now, it should be clear to you that many regions of the world, including Africa, have experienced multiple population replacements whether pre-Neolithic or post-Neolithic. Today's SS Africans are vastly different from the SS Africans of just a few ten thousand years ago; they are even racially totally different.

terryt said...

"we'd expect the pre-Bantu diversity to be huge everywhere (certainly much higher than, say, New-Guinean levels or South American levels)"

Not necessarily. New Guinea and South America are heavily forested (and mountainous). Such regions lend themselves to linguistic (and genetic) diversity. Much of populated Africa was more open woodland although it is interesting that where populations have moved into jungle they seem to have adopted neighbouring languages. Africa linguistically is probably more akin to Australia where I don't think there is the linguistic diversity of New Guinea in spite of it having a larger area.

"you have to deal with possibility that the human population was mostly continuous and berely disturbed here in the last 40kY or so. So far you can't say the same about any part of Africa".

True.

"the diversity in Africa was supposed to be much much higher than elsewhere pre-Neolithic, so that even a wipe-out should leave at least some hint of that former diversity intact in isolated pockets. We see very little of that. Why did the 'linguistic culling' have to be so complete?"

Perhaps because contact across much wider regions has always been possible in Africa (outside jungle and desert) than in most other regions.

German Dziebel said...

@Teo

"The Eurasian situation is supposed to be an already smaller diversity reduced to very little after countless Neol. Expansions for a long time, whereas the African one is supposed to be huge diversity reduced to very little after a handful of expansions (certainly fewer than Eurasia, and beginning later). Why? That is what is unique and requires explanation."

Your point is well taken, and it's true that there were more language extinctions going on outside of Africa than in Africa in the past 40,000 years, including LGM, Neolithic replacements, not to mention the most recent, post-1492 language loss in the New World. PNG, the New World, Caucasus are the refugia that have retained ancient levels of linguistic diversity and population fragmentation. There are no comparable refugia in Africa.

There's a very simple explanation for this: Africa is not as ancient, as a behaviorally modern human occupied region, as Papua New Guinea, the New World or parts of Asia. As we can see from the distribution of the Y-DNA DE clade, it's not found in America or Papua New Guinea suggesting that they had been colonized before the expansion of this clade in Africa and parts of Asia. Also, it's precisely in the New World and PNG that we see the highest frequencies of Denisovan alleles. May be a coincidence or an artifact, but could be a systemic property related to the linguistic diversity phenomenon.

Broadly speaking, East Africa has the largest linguistic diversity in Africa, with all major language families represented there via their most divergent branches (Kordofanian, Hadza, Sandawe, etc.). East Africa must have been then the route by which Africa was colonized by behaviorally modern humans.

The question of course that looms large, under this scenario, is what to do with genetic diversity in Africa. The simplest solution is to consider all the particularly divergent branches in Africa as
products of admixture with "anatomically modern humans" who, as Richard Klein would confirm, didn't have languages and other aspects of modern human behavior.

There may be other explanations (cycles of genetic divergence followed by admixture in Africa, increased mutation rate in Africa, selection, relaxation of inbreeding depression, etc.) but archaic admixture may be the easiest to visualize.

In all the refugia areas outside of Africa (New World, PNG, caucasus), we observe reduced levels of genetic diversity. In Africa, Hadza also show reduced genetic diversity. All of this may suggest that African diversity is a product of both a) archaic admixture and b) intraspecific admixture among various human populations. Hadza is an isolate that maintained the original high inbreeding rates, low heterozygosity, etc., while all other African populations absorbed a lot of gene flow.

Teo. said...

@German

Yes. There could be other explanations, but it seems increasingly likely that the “cultural phenomenon of language” (as opposed to the biological capacity that allows it) came later to much of SS Africa. I doubt Hofmeyer-type people or their immediate successors left any linguistic descendants, either. It could be even more recent, perhaps a lot more.

German Dziebel said...

@Teo

I just finished a blog post in which I discuss Joseph Jordania's hypothesis that low linguistic diversity in Africa and Europe vs. the New World, Papua New Guinea, etc. comes from the fact that in Africa and Europe humans shifted to articulated speech (from a "musical protolanguage") later than in the New World , PNG and Asia. I argue against Jordania's theory but it's a very clear way to explain a pattern that others dismiss as epiphenomenal.

Teo. said...

Thanks, German. I've checked the post. I'll just reinforce one point here.

I think we should be careful not to confuse the human capacity for language with its physical manifestation(s).

I think it's perfectly possible that the capacity for language evolved only once and then began to be explored universally through prosody and music (as well as gesture), whereas articulated speech as we know it evolved later out of these previous uses, and then spread through cultural diffusion.

This is anathema to orthodox Chomskyans, but certainly not as far-fetched as it seems. Some phonologists, such as April MacMahon, have expressed similar views.

terryt said...

"I think it's perfectly possible that the capacity for language evolved only once and then began to be explored universally through prosody and music (as well as gesture)"

To me it is very likely that the capacity for speech involves far more than just a single gene. There were probably a series of genes that sprang up in different places and at different times, to spread from those separate regions through the human species.

"articulated speech as we know it evolved later out of these previous uses, and then spread through cultural diffusion".

I agree that the final capacity for speech as we know it probably came to fruition in a single region and spread from there. At the moment we have no way of knowing when that happened, or where. However we are all free to guess.