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 thought, Modern 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.
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.