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East Africa, 60,000 to 80,000 years ago. The relative stasis of early humans was being shaken by a series of population expansions. The last one went global, spreading out of Africa, into Eurasia and, eventually, throughout the whole world (Watson et al., 1997). Those humans became us.
This expansion took place at the expense of more archaic humans: Neanderthals in Europe, the Middle East, and Central Asia; Denisovans in East Asia; and mysterious hobbit-like creatures in parts of Southeast Asia.
And in Africa itself? We know less about those archaic humans, partly because the archeological record is so patchy and partly because ancient DNA does not survive as long in the tropics. Over time, the double helix breaks down, and this decomposition occurs faster at higher ambient temperatures. We’ll probably never be able to reconstruct the genome of archaic Africans.
Yet they did exist. Surprisingly, they held out longer in parts of Africa than their counterparts did much farther away. A Nigerian site has yielded a skull that is only about 16,300 years old and yet looks intermediate in shape between modern humans on the one hand and Neanderthals and Homo erectus on the other. It resembles the skull of a very early modern human, like the ones who once lived at Skhul and Qafzeh in Israel some 80,000 to 100,000 years ago (Harvati et al., 2011; Stojanowski, 2014).
Archaic humans also held out in southern Africa. The Broken Hill or Kabwe skull, from Zambia has been dated to 110,000 years ago and looks very much like a Homo erectus (Bada et al., 1974; Stringer, 2011). This pre-sapiens human seems to have lasted into much later times. Hammer et al. (2011) found that about 2% of the current African gene pool comes from a population that split from ancestral modern humans some 700,000 years ago. They dated the absorption of this archaic DNA to about 35,000 years ago and placed it in Central Africa, since the level of intermixture is highest in pygmy groups from that region.
Cognitive modernity: less awesome on its home turf
Why did archaic humans survive longer in Africa than elsewhere? Some of them were more advanced than the Neanderthals or Denisovans, and perhaps better able to fend off invasive groups. This was the case with archaic West Africans, who seem to have been transitional between pre-sapiens and sapiens. They may have met modern humans on a more level playing field while enjoying the home team advantage.
On the other hand, archaic southern Africans look clearly pre-sapiens. What was levelling their playing field? Perhaps modern humans had advantages that were more useful outside Africa. Klein (1995) has argued that this advantage was cognitive, specifically a superior ability not only to create ideas but also to share them with other individuals via language—in a word, culture. This cognitive edge may have been more useful outside the tropics, where the yearly cycle forced humans to plan ahead collectively and keep warm collectively by building shelters and making garments. The result was a much wider range of human technology: deep storage pits for meat refrigeration; hand-powered rotary tools; kilns for ceramic manufacture; woven textiles; eyed sewing needles; traps and snares; and so on (Frost, 2014).
Modern humans were thus pre-adapted in Africa for later success elsewhere. We see this in their rapid penetration of cold environments unlike anything in their place of origin. By 43,500 years ago, they were already present in Central Europe at a time when it was barren steppe with some boreal forest in sheltered valleys (Nigst et al., 2014).
Pre-adaptation is a recurring oddity of evolution. A new ability may initially be a bit helpful and only later truly awesome. Does this mean that evolution anticipates future success? Well, no. It’s just that the difference between failure and success—or between so-so success and the howling kind—often hinges on a few things that may or may not exist in your current environment. By moving to other environments, you increase your chances of finding one that will put your talents to better use. Success is fragile, but so is failure.
Bada, J.L., R.A. Schroeder, R. Protsch, & R. Berger. (1974). Concordance of Collagen-Based Radiocarbon and Aspartic-Acid Racemization Ages, Proceedings of the National Academy of Sciences (USA), 71, 914-917.
http://www.pnas.org/content/71/3/914.short
Frost, P. (2014). The first industrial revolution, Evo and Proud, January 18
/pfrost/the-first-industrial-revolution/
Hammer, M.F., A.E. Woerner, F.L. Mendez, J.C. Watkins, and J.D. Wall. (2011). Genetic evidence for archaic admixture in Africa,Proceedings of the National Academy of Sciences (USA), 108, 15123-15128.
http://www.u.arizona.edu/~flmendez/papers/Hammer_2011.pdf
Harvati, K., C. Stringer, R. Grün, M. Aubert, P. Allsworth-Jones, C.A. Folorunso. (2011). The Later Stone Age Calvaria from Iwo Eleru, Nigeria: Morphology and Chronology. PLoS ONE 6(9): e24024. doi:10.1371/journal.pone.0024024
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0024024
Klein, R.G. (1995). Anatomy, behavior, and modern human origins,Journal of World Prehistory, 9, 167-198.
http://link.springer.com/article/10.1007/BF02221838
Nigst, P.R., P. Haesaerts, F. Damblon, C. Frank-Fellner, C. Mallol, B. Viola, M. Gotzinger, L. Niven, G. Trnka, and J-J. Hublin. (2014). Early modern human settlement of Europe north of the Alps occurred 43,500 years ago in a cold steppe-type environment, Proceedings of the National Academy of Sciences (USA), published online before print
http://www.pnas.org/content/early/2014/09/16/1412201111.short
Stojanowski, C.M. (2014). Iwo Eleru’s place among Late Pleistocene and Early Holocene populations of North and East Africa, Journal of Human Evolution, epub ahead of print
http://www.sciencedirect.com/science/article/pii/S0047248414000876
Stringer, C. (2011). The chronological and evolutionary position of the Broken Hill cranium. American Journal of Physical Anthropology,144(supp. 52), 287
Watson, E., P. Forster, M. Richards, and H-J. Bandelt. (1997). Mitochondrial footprints of human expansions in Africa, American Journal of Human Genetics, 61, 691-704. 0024024
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0024024
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There was someone a while back who posted a comment on E&P with a link to study of chimp society. It said the males had expanded chests and looked scared apart from the boss chimp. I have read the boss chimp tends to bash up females so he and his pals can mate with her. Chimps are known to make war on neighbouring chimps too. For chimps avoiding violence from rival males and rival groups seems to have been a salient problem.
Bonobos:”Bonobos are much more likely to keep the peace by offering a sexual favor, whereas a chimpanzee’s first instinct is to secure dominance through battle. In chimp groups, the highest-ranking male is the only one allowed to mate with the females, but in bonobo cultures, everyone has sexual freedom”.
So the adaptations of the archaic-ancestry humans might have been more like chimps (where there is ever present risk of violence adaptation to it would be useful), while modern humans were more like bonobos. There is a belief that bonobos would not be able to survive around chimps, but bonobo don’t have to deal with chimps as bonobos only live in the resource rich and isolated bend of the Congo basin. Bonobos are really smart Bonobo Stone Tools as Competent as Ancient Human?. Genius ape Kanzi.
Anyway, maybe modern humans’ intelligence had something to do with them having less need to be fearful, or aggressive.
Hey Peter, its true that jews have a high rate of neanderthal genes?
I doubt it. The first signs of human culture (cavepaintings, music instruments and sculptures) are from Europe, where humans and Neanderthals were competing with each other.
I have read a modest amount about evolution (lots of the Gould books included), and with that reservation noted about it, as with this piece by Mr. Frost, one of the most interesting aspects of it doesn’t seem explored much, despite what appears (again, to me at least) to be its huge importance.
I’m not sure exactly how to define it, but that relatively unremarked upon aspect seems to me to be the lack of attention paid to the … social/cultural contribution to evolution in the form of intra-species aggression.
That is, while Mr. Frost here so typically talks so much (if not almost exclusively) about the evolution of physiological adaptations and how no doubt crucial they are to evolutionary success, look at what happened, say, to the neanderthals.
After all for a long long time they seem to have had plenty of adaptations to do well and spread wide.
But what seems to have happened to them? Did they lose their adaptations? No. Unlikely. Indeed the logic of natural selection would argue that if anything they gained some.
Instead of course their demise seems to be tied to the influx of more advanced humanoids, and its very difficult for me to believe that what happened to the neanderthals en masse wasn’t their being essentially massacred by their new neighbors. Just like Mr. Frost off-handedly mentions the reasonable proposition that archaic humans in Africa might have persisted longer than others elsewhere because of a better ability to “fend off” their more modern wanna-be new neighbors.
Or perhaps as another possible example the eradication of the Dorset arctic people with the influx of the more modern Innuit. With the former not even seeming to be in all that direct a competition with the Innuit for resources given that they seem to have been far more sea-based focused than the early Innuit at least.
Moreover this dynamic also seems to resonate with what we see in social animals, often to absolutely characteristic degree: One wolf pack gets too big for its territory and splits and one part moves elsewhere and there it doesn’t just compete “fairly” for the resources there, instead what does one inevitably see but fierce battles to the death. Genocidal in nature really.
Since this implicates matters of psychological mentality and instincts and emotions I suppose this ventures ultimately into the realm of socio-biology/evolutionary psychology. But, nevertheless, I can’t help but believe that it is *just*as important a part of the evolutionary story of what we see today as the story of the evolution of physiological adaptations to environment.
I.e., with many species, the reason they are here today is that not only because they are to some successful degree physiologically adapted to their environment, but also only because they were conquerers essentially. They didn’t just “outcompete” their relatives in the sense of being better hunter-gatherers or even farmers: They slaughtered out the others.
And again, that this is *just* as important a part of the story as the physiological adaptations to environment have been for many species.
If so seems to say something very deep and profound about our nature since one can hardly imagine that we are one of the species that this dynamic did not work its will with.
By my way of thinking, the hulking barrel chested Cro Magnons with their enormous heads seem adapted to being big boss man rather than fiddling about with tools, and they were not replaced–the later Europeans were their descendants. Brian Hare /Bruce Hood’s theory is that there was a process similar to wolf domestication into domestic dog or the Russian fox domestication experiment, and it made the Europeans progressively smarter. The sharpest reduction in size was during the Magdalenian.
Well thank you Sean not only for the ideas to chew on but the cite to some apparent authors to look into.
Animals in Europe may well have been a lot easier to hunt that the ones in Africa, which had evolved with human predation. The Falkland Islands wolf – ‘foolish dog o’ the south’ was easy to kill because in had no fear. Cro magnons were oversized bull necked thugs, and to me they look like they evolved where the main problem was not getting the groceries, but fighting for females.
Sean,
I don’t know about modern humans being less warlike. There does seem to be a cognitive difference, with Neanderthals relying more on domain-specific hardwired algorithms. Cochran and Harpending wrote about this point in one of their outtakes:
“Our favorite hypothesis is that Neanderthals and other archaic humans had a fundamentally different kind of learning than moderns. One of the enduring puzzles is the near-stasis of tool kits in early humans – as we have said before, the Acheulean hand-axe tradition last for almost a million years and extended from the Cape of Good Hope to Germany, while the Mousterian lasted for a quarter of a million years. Somehow these early humans were capable of transmitting a simple material culture for hundreds of thousands of years with little change. More information was transmitted to the next generation than in chimpanzees, but not as much as in modern humans. At the same time, that information was transmitted with surprisingly high accuracy. This must be the case, since random errors in transmission would have caused changes in those tool traditions, resulting in noticeable variation over space and time – which we do not see.
It looks to us as if toolmaking in those populations was, to some extent, innate: genetically determined. Just as song birds are born with a rough genetic template that constrains what songs are learned, early humans may have been born with genetically determined behavioral tendencies that resulted in certain kinds of tools. Genetic transmission of that information has the characteristics required to explain this pattern of simple, near-static technology, since only a limited amount of information can be acquired through natural selection, while the information that is acquired is transmitted with very high accuracy.”
http://isteve.blogspot.ca/2009/01/neanderthals.html
Peltast,
Not that I know of. The consensus seems to be that Ashkenazi Jews are about half Middle Eastern and half European by origin. Strangely enough, their European origin looks more Italian than Slavic (I suspect “Italian” is a proxy for the European population that existed along the Rhone valley over a thousand years ago, this having been one of the main areas of Jewish settlement).
A group than merely reduced the level of intra-group aggression could have less mortality and more numbers, and doom all the the other groups even if the the nicey- nicey group were relatively pacifistic toward other groups. Better to be genes of a cave wimp in the nicey-nicey (and hence flourishing) group that the genes of a big boss man in a relatively dwindling group (where only the strong are respected).
Maybe what C &H say is correct for early CroMagnons (who I believe are supposed to have used thrusting not throwing spears). But there is a lot of difference in the robustness of the skeleton between CroMagnons and Magdelenian hunters (and women and men).
I think the steppe tundra sexual selection hypothesis can be pushed further; tools get developed by paying attention to what others are doing and showing others what to do. To me that is intra -group communication, which is not only more like the bonobos’ than the common chimps’ behaviour, it’s more like women’s behaviour than men’s.