October 20, 2008

The Middle to Upper Paleolithic record of western Eurasia

Journal of Human Evolution doi:10.1016/j.jhevol.2008.04.002

At the end of the 14C time scale—the Middle to Upper Paleolithic record of western Eurasia

Olaf Jöris, and Martin Street


The dynamics of change underlying the demographic processes that led to the replacement of Neandertals by Anatomically Modern Humans (AMH) and the emergence of what are recognized as Upper Paleolithic technologies and behavior can only be understood with reference to the underlying chronological framework. This paper examines the European chronometric (mainly radiocarbon-based) record for the period between ca. 40 and 30 ka 14C BP and proposes a relatively rapid transition within some 2,500 years. This can be summarized in the following falsifiable hypotheses: (1) final Middle Paleolithic (FMP) “transitional” industries (Uluzzian, Chatelperronian, leaf-point industries) were made by Neandertals and date predominantly to between ca. 41 and 38 ka 14C BP, but not younger than 35/34 ka 14C BP; (2) initial (IUP) and early (EUP) Upper Paleolithic “transitional” industries (Bachokirian, Bohunician, Protoaurignacian, Kostenki 14) will date to between ca. 39/38 and 35 ka 14C BP and document the appearance of AMH in Europe; (3) the earliest Aurignacian (I) appears throughout Europe quasi simultaneously at ca. 35 ka 14C BP. The earliest appearance of figurative art is documented only for a later phase ca. 33.0/32.529.2 ka 14C BP. Taken together, the Middle to Upper Paleolithic transition appears to be a cumulative process involving the acquisition of different elements of “behavioral modernity” through several “stages of innovation.”



terryt said...

"the Middle to Upper Paleolithic transition appears to be a cumulative process involving the acquisition of different elements of 'behavioral modernity' through several 'stages of innovation'".

I'd hope most of us would have already assumed that. After all that's how evolution usually proceeds. Or do some here believe "behavioural modernity" sprang up overnight in just some single small group?

eurologist said...

It's not evolution in this case, though. The time scales are way too short.

I really like the paper and cannot find much fault with it.

Basically, with strict credibility limits on available data, the autors come to the conclusion that we had a period of early/initial Upper Paleolithic carried by AMHs about 2,500 years before the CI eruption (~40,000 years ago), and Neanderthals largely disappearing before then or latest, during that time.

Just after the CI eruption, the climate turned cold, and both events in combination meant a severely restricted habitat, leading to the Aurignacian inventions. Here I slightly disagree with the authors.

I believe that the initial AMH occupation of Europe was via somewhat atypical, robust ("tough") people inclined and uninhibited to venture into this area, which could explain reports of mixed-in Neanderthal-like skeletal signatures. I don't know if any interbreeding or much cultural exchange occurred, but whether aided by diseases or dogs, getting rid of the Neanderthals did not seem to be much of a problem for these folks across most of Europe within a millennium, or so, despite the low numbers of AMH individuals.

When the known usable area drastically shrank due to the eruption and onset of the cold event, it certainly would have spurred competition and innovation. However, I think that the initial group of AMHs was too narrow (genetically and culturally) to respond effectively on its own. I believe that the large pool of AMHs to the East would have been in a better position to do this and to deliver both people and cold-adapted culture shortly after the onset of the event.

Apart from the presence of Neanderthals, the earliest/initial UP folks in Europe encountered a fairly benign, moderate-temperature environment with many obvious and easy resources. They were able to live an easy, unsophisticated life because of that, and their marginal tool set confirms it.

The mainstream Aurignacians clearly had a different challenge and world view, altogether.

Yet, the ~5,000 years span between the earliest European AMHs and mainstream Aurignacian (with associated tool sets and figurative art) is way too short for any type of regular evolution. More likely, the changes were able to happen quickly due to the novel development of rapid cultural (and people) pathways across Europe and the adjacent Near East.

terryt said...

"It's not evolution in this case, though. The time scales are way too short". Surely evolution is simply just the product of a longer series of such small changes?

eurologist said...

Sure there are changes over a span of a few thousand years, and they do add up. But most people think the UP revolution was cultural and driven by geographic and climate factors, migration, and a newly-developing network that span Europe and Western Asia - not by any significant genetic change in humans during that time.

IMO there likely was significant ongoing evolution (and more importantly, selection) during the preceding 20,000 years, but by 40,000 years ago the necessary pieces had mostly come together. And even if researchers would find that the DNA of the earliest UP people in Europe is different from those 5,000 years later (like the bones look different), that could just be a temporary selection effect - in the big picture, perhaps nothing changed.

What I mean by that is that the first AMHs arriving in Europe were a very small subset of the people living in Asia. Surely, more people arrived later during opportune times. 35,000 years ago, the gene pool would have been a lot wider than 40,000 ago, and likely more representative of Western Asia, although still a subset, and by then with its own peculiar selections.

In general, I like to think of what makes us modern as a mosaic or entire bakery of pies made of many ingredients. Today, most of us have a good chance of having inherited a lot of raisins in the speaking, abstract thinking, social thinking, music, and arts departments - each themselves made up of their own pie with hundreds of raisins.

100,000 years ago, or even 60,000 years ago, only a few lucky ones had a lot of raisins, and it took a while for the raisins to become more widely spread throughout the gene pool. Environmental and population strain certainly helped with this process, while it is slowed when food is plenty and life in general is easy.

terryt said...

"But most people think the UP revolution was cultural". Totally agree. I also suspect the Levallois' spread was cultural, not necessarily associated with genetic change. As, presumably, the hand-ax or even the original Oldowan. Although in the latter case especially groups with it would certainly have been at an evolutionary advantage.

I like your bit about raisins. But I would add genes to "speaking, abstract thinking, social thinking, music, and arts departments". Not all genes have made it to all populations. But to believe, because of that, these populations are somehow 'inferior' is not at all justified. (I've just been reading, and commenting, about 'race' at another blog).

Unknown said...

Dear Eurologist,

I don't agree with you that the first AMH disappeared by a new stock or that they have been wiped out by a natural disaster like the Campanian ash spread in ca 40000 BC. Proof of my words is the fact that the types found in Kostenki - Borshchevo of Russia are including Negroid types like the Kostenki XIV (Markina Gora) individual.
This particular racial type survives in later times through out Europe and it is the famous Grimaldi type!!!
This race is found from the Iberian peninsula, to Italy and up the Crimea and finally Voronezh.