Tuesday, 24 March 2009

Blombos Cave

Blombos Cave (BBC) is located near Still Bay on the southern Cape coast in South Africa. It is 100m (330ft) from the coast and 35m (115ft) above sea-level. The site was discovered by Christopher Henshilwood in 1991 and has been excavated regularly since.

The site is notable for the discovery of two pieces of ochre, 73,000 years old, engraved with abstract designs; 75,000 year old tick shell (Nassarius kraussianus) beads; 70,000 year old bone tools; and evidence of shellfish collection and possibly fishing 140,000 years ago. All of these are considered to be markers of modern human behaviour, emerging millennia before the so-called “human revolution” 50,000 years ago.

Three MSA phases have been excavated; these are separated from overlaying the LSA by wind-blown sediments. The phases, from top to bottom, are known as M1, M2 and M3. Dating by Optically Stimulated Luminescence (OSL) and Thermoluminescence (TL) methods has yielded dates of c. 73,000 years for the M1 Still Bay phase (oxygen isotope stage OIS-5a/4); c. 77,000 years for the M2 Still Bay phase (OIS-5a); c. 80,000 years for the M2 low density (hiatus) phase (layers CGAA, CGAB, CGAC); and c. 125-140,000 years for the M3 phase (OIS-5e/6). The M1 layer is separated from the more recent LSA deposits by a hiatus layer of sterile aeolian (wind-blown) sand; M2 and M3 are also separated by a hiatus layer. M1 comprises layers CA, CB, CC, CD and CE; M2 comprises CFA, CFB/CFC and CGA; M3 comprises CGB/CH, CI, CJ, CK, CL, CM, CN, CO and CP. These occupation layers are generally less than 10cm thick, suggesting sporadic, brief periods of occupation punctuated by long periods when the cave was not in use (Henshilwood, 2007; Henshilwood et al, 2001; Jacobs et al, 2006; Tribolo et al, 2006).

All three phases of occupation have evidence of extensive exploitation of aquatic resources including large fish, shellfish, seals and dolphins. Land mammals were extensively hunted, with mole-rats making a frequent appearance on the menu (Henshilwood et al, 2001; Henshilwood, 1997).

All three phases have wood-ash scattered indicating regular use of fire for cooking purposes.

Still Bay technology:
Bifacial foliate points associated with the Still Bay tradition were recovered from the M1 and upper M2 phases of Blombos. Earlier phases contain lithic artefacts that do not fit into existing MSA 1 typographic traditions. They represent an earlier phase of the MSA (Henshilwood, 2007, citing Soressi & Henshilwood, 2004, unpublished paper).

Still Bay points are soft hammer worked points, predominantly made on
silcrete. They are typically bifacially retouched, narrowly elliptic to lanceolate shaped tools, with two sharply pointed apices. There is a distinct preference for silcrete as a raw material. Increased use of finer-grained stone, relative to earlier MSA phases, is a characteristic of the Still Bay (Henshilwood et al, 2001). The small, highly-standardised bifacial Still Bay stone points are a marker of behavioural change (Klein, 1999).

Bone tools:
Bone tools are known from the M1 and upper M2 phases, corresponding to the Still Bay complex. The tools include points and awls. The majority are shaped on bone fragments or splinters removed from long bone shafts although in some cases the whole bone is shaped. Bovid bone is most widely used but marine mammal bone and a single bird bone were also employed.

Morphology and use-wear patterns suggest most MSA bone tools (85%) were used to perforate fairly soft material such as well-worked hides, possibly during the manufacture of clothing and other items, probably being used as awls. However three artefacts have been interpreted as projectile points, being visually similar to bone projectile points from various LSA and ethnographic collections. These are symmetrical both at the tip and in overall shape, are worked on the entire surface and tend strongly toward a circular cross-section. In contrast, awls are often asymmetrical in shape, may be incompletely worked and mostly have an elliptical cross-section. Blombos cave bone tools interpreted as awls conform to their LSA counterparts. One of the putative projectile points shows signs of hafting; probably all three were.

MSA bone tools at Blombos Cave were extensively used after manufacture, in many cases re-used even after tip breakage, suggesting that tools were maintained at the site. Tools were probably discarded when the breakage occurred nearer the midpoint, rather than the tip, making the tool too small to hold for further use. Projectile points were probably discarded when they broke in the haft.

One question is that if the people of the African MSA possessed the cognitive ability to make bone tools, why have so few been found in the archaeological record in comparison to Upper Palaeolithic Europe? One possibility is that MSA people only worked bone infrequently. African hardwoods are also suitable for the manufacture of tools such as awls and points, are easier to work than bone and may thus have been used in preference. Wood is rarely preserved in MSA sites, so such tools would be absent from the archaeological record. Another possibility is that bone tools in the MSA may have served specific, time limited functions within small populations that were relatively isolated, in contrast to the demographic picture the Upper Palaeolithic in Europe.

Bone tool use in Africa may have been the exception rather than the rule and purely practical considerations may also be a factor. Though generally bone fares better than wood, taphonomic factors do still dictate against its preservation at many MSA sites. In addition, many MSA sites were excavated before modern recovery techniques became available and much evidence may have been lost.

There is currently a lack of consensus on the evolutionary significance of bone tool technology. It is not known why humans began to produce bone tools or the incidence and consequence of their manufacture in and use in prehistoric societies. Consequently we do not know whether bone tool technology represents one attribute of cultural modernity or that it results from punctuated cultural adaptations that have little evolutionary significance. The association of formal or elaborate bone artefacts and the Upper Palaeolithic in Europe has been used to argue that bone technology is allied with cultural modernity, anatomically modern humans and a package of other euro-centrically derived modern cultural behaviours, but what is observed in one region does not necessarily constitute a general paradigm

Bone tools from Blombos cave may also reflect symbolic behaviour. The techniques used to manufacture objects in many societies are more often a reflection of their symbolic rather than utilitarian function. The careful deliberate polishing of the Blombos MSA bone artefacts interpreted as projectile points has no apparent function and seems to be a technique used to give a distinctive appearance and/or an ‘‘added value’’ to this category of artefacts.

In contemporary hunter-gatherer societies a consequence of the symbolic value of hunting weapons is that they are produced and handled solely by men. The differences in the manufacturing techniques between the projectile points used for hunting and awls used domestically may well reflect the different symbolic functions of these activities; differences that must have been linguistically transmitted (Henshilwood, 2007; Henshilwood et al, 2001).

More than 2000 pieces of ochre have been recovered from the M1 and M2 phases. Two pieces (AA 8937 and AA 8938) from the M1 phase have been unequivocally engraved. Both pieces have a cross-hatched pattern. On AA 8938 this is bounded top and bottom by parallel lines, with a third parallel line running through the middle. The choice of raw material, the situation and preparation of the engraved surface, engraving techniques and final design for both pieces are similar, indicating a deliberate sequence of choices and intent. They are not isolated occurrences or the result of idiosyncratic behaviour (Henshilwood, 2007). Fully syntactical language is arguably an essential requisite to share and transmit the symbolic meaning of beadworks and abstract engravings such as those from Blombos Cave (Henshilwood et al, 2004).

More than 65 “tick” shell (Nassarius kraussianus) beads have been recovered from the MSA levels at Blombos Cave. These shells occur only in estuaries and were probably brought to the site from the Duiwenhoks and Goukou rivers, located around 20km from the cave. This distance rules out the shell having been deposited at the cave by non-human predators. While it is possible that the tick shells were collected as food, the time taken to extract the modest quantities of nutrient available per shell makes this unlikely given the availability of larger shellfish and fish.

All the shells are adult, indicating deliberate selection for size, and arguing again against their presence being the result of non-human agency. All are perforated dorsally with 88 percent having a medium sized perforation near the lip, confirming the perforations to be man-made and deliberate rather than the result of some natural process. A sharp tool, elliptical in section, was most likely used to make the perforations.

The beads show signs of wear from threading with cord or gut and contact with human skin, suggesting they were worn as bracelets or necklaces for a considerable period of time. Traces of ochre suggest possible colouring of beads, though it could also have come from body-paint. Beads were found in groups displaying similar size, colour, perforation type and use-wear pattern, suggesting such groups represented single beadwork items. Wearing of personal ornaments implies a comprehension of self-awareness or self-recognition. As with the engraved ochre, the existence of syntactic language is arguably implied (Henshilwood et al, 2004; d’Errico et al, 2005; Henshilwood, 2007).


Francesco d’Errico, Christopher Henshilwood, Graeme Lawson,Marian Vanhaeren, Anne-Marie Tillier, Marie Soressi, Frederique Bresson, Bruno Maureille, April Nowell, Joseba Lakarra, Lucinda Backwell, and Michele Julien (2003): Archaeological Evidence for the Emergence of Language, Symbolism, and Music – An Alternative Multidisciplinary Perspective, Journal of World Prehistory, Vol. 17, No. 1, March 2003.

Francesco d’Errico, Christopher Henshilwood, Marian Vanhaerend, Karen van Niekerke (2005): Nassarius kraussianus shell beads from Blombos Cave: evidence for symbolic behaviour in the Middle Stone Age, Journal of Human Evolution 48 (2005) 3-24.

Frederick E. Grine, Christopher S. Henshilwood and Judith C. Sealy (2000): Human remains from Blombos Cave, South Africa: (1997–1998 excavations), Journal of Human Evolution (2000) 38, 755–765.

Grine F.E. & Henshilwood C.S. (2002): Additional human remains from Blombos Cave, South Africa: (1999–2000 excavations), Journal of Human Evolution (2002) 42, 293–302.

C. S. Henshilwood (1997): Identifying the Collector: Evidence for Human Processing of the Cape Dune Mole-Rat, Bathyergus suillus, from Blombos Cave, Southern Cape, South Africa, Journal of Archaeological Science (1997) 24, 659–662.

C. S. Henshilwood, J. C. Sealy, R. Yates, K. Cruz-Uribe, P. Goldberg, F. E. Grine, R. G. Klein, C. Poggenpoel, K. van Niekerk, I. Watts (2001): Blombos Cave, Southern Cape, South Africa: Preliminary Report on the 1992–1999 Excavations of the Middle Stone Age Levels, Journal of Archaeological Science (2001) 28, 421–448.

Christopher S. Henshilwood, Francesco d’Errico, Curtis W. Marean, Richard G. Milo, Royden Yates (2001): An early bone tool industry from the Middle Stone Age at Blombos Cave, South Africa: implications for the origins of modern human behaviour, symbolism and language, Journal of Human Evolution (2001) 41, 631–678.

Christopher S. Henshilwood, Francesco d’Errico, Royden Yates, Zenobia Jacobs, Chantal Tribolo, Geoff A. T. Duller, Norbert Mercier, Judith C. Sealy, Helene Valladas, Ian Watts, Ann G. Wintle (2002): Emergence of Modern Human Behavior: Middle Stone Age Engravings from South Africa, Science 295, 1278 (2002).

Christopher Henshilwood, Francesco d’Errico, Marian Vanhaeren, Karen van Niekerk, Zenobia Jacobs (2004): Middle Stone Age Shell Beads from South Africa, Science 16 April 2004: Vol. 304. no. 5669, p. 404

Henshilwood C (2007): Fully Symbolic Sapiens behaviour: Innovation in the Middle Stone Age at Blombos Cave, South Africa, Rethinking the human Revolution, Macdonald Institute.

Zenobia Jacobs, Geoffrey A.T. Duller, Ann G. Wintle, Christopher S. Henshilwood (2006): Extending the chronology of deposits at Blombos Cave, South Africa, back to 140 ka using optical dating of single and multiple grains of quartz, Journal of Human Evolution 51 (2006) 255-273.

McBrearty S & Brooks A (2000): The revolution that wasn’t: a new interpretation of the origin of modern human behaviour, Journal of Human Evolution (2000) 39, 453–563.

Scarre C (2005) (Ed): “The human past”, Thames & Hudson.

C. Tribolo, N. Mercier, M. Selo, H. Valladas, J.-L. Joron, J.-L. Reyss, C. Henshilwood, J. Sealy and R. Yates (2006): TL dating of burnt lithics from Blombos Cave (South Africa): further evidence for the antiquity of modern human behaviour, Archaeometry 48, 2 (2006) 341–357.

© Christopher Seddon 2009

Tuesday, 17 March 2009

Modern humans & Neanderthals in the Levant

The first evidence for modern humans leaving Africa comes from the Levant, where the caves of Mugharet es-Skhul and Jebel Qafzeh (Israel) have yielded the remains of over 20 individuals, many of whom appeared to have been intentionally buried. The remains have been dated to between 110,000-90,000 years ago on the basis of ESR and luminescence dating. Though possessing some archaic features such as robustness, they are essentially modern, anatomically lying within the range of Homo sapiens.

However Neanderthal burials are known from much later at Kebara, Amud and Tabun (Israel), dating to between 60,000-50,000 years ago; and Shanidar Cave (Iraq) and Dederiyeh Cave (Syria) dating to as late as 45,000 years ago: this suggests a later re-occupation of the region by Neanderthals.

Modern humans had returned to the region by 35,000 years ago, and possibly as early as 45,000 years ago.

The likeliest explanation is that the ranges of modern humans and Neanderthals fluctuated back and forth in accordance with climate change. Whenever the climate was warm, the region would be occupied by modern humans; when it was cool it would be occupied by Neanderthals. Faunal evidence shows that in cooler times Palearctic fauna spread down from Europe, but when the climate warmed Afrotropical fauna would move in and replace the Palearctic. The two human species were merely “going with the flow” like any other animal species.

The lithic technology employed by both human species was, up until 50,000 years ago, very similar, being fairly typical Middle Palaeolithic/MSA and it has been described as Levalloiso-Mousterian, dominated by the Levallois reduction technique.

Lieberman & Shea (1994) suggest that hunting strategies between the two species did in fact differ. Analysis of seasonally-deposited cementum in the teeth of mountain gazelle and other ungulates indicates that the Neanderthals hunted these animals over both dry and wet seasons, but modern humans only hunted them during the dry season. Analysis of the lithic hunting technology further suggests more extensive hunting by the Neanderthals. Far more points are found at Neanderthal sites; these show greater signs of wear; and raw materials were procured only a short distance away from each site.

Lieberman & Shea interpret this to mean that the Neanderthals practiced a locally-intensive “radiating mobility” strategy. Their activities were primarily organized from large general-purpose sites, with more specialized or seasonal activities being carried out at smaller sites on the periphery of the main one.

By contrast, the modern humans practiced a seasonal-based “circulating mobility” strategy, living at different sites at different times of the year to facilitate exploitation of seasonal resources.

Both strategies have their pros and cons. The “radiating mobility” strategy permits an increased capacity for storage and investment in material culture (site facilities and hard-to-transport items). The main problem is that resources around the central camp become depleted due to year-long exploitation and a law of diminishing returns begins to effect hunting and foraging activities.

The “circulating mobility” strategy avoids these problems by ability to relocate to sites near periodically-abundant resources, which will then have a year to recover after the group have moved on to the next site. The drawbacks are that the group has to do without items that cannot readily be moved from site to site.

These differing strategies may highlight behavioural differences between modern humans and Neanderthals, with the “circulating mobility” strategy arising from modern human behaviour (which it is inferred the Neanderthals were incapable of). Another possibility is that the heavily-built Neanderthals were not physically adapted for a highly-mobile lifestyle.

The final, conclusive re-occupation of the Levant by modern humans, followed by their expansion into Europe has been taken to support the “Big bang” theory of behavioural modernity arising only 50,000 years ago, after which modern humans were able to overcome the “climate barrier” and move into Europe. This theory is however predicated on a modern human migration out of Africa proceeding via the Levant rather than taking a southern route across the Red Sea, a possibility rejected by some authorities such as Stephen Oppenheimer (Oppenheimer, 2003).


Daniel E. Lieberman and John J. Shea (1994): Behavioral Differences between Archaic and Modern Humans in the Levantine Mousterian, American Anthropological Association.

Oppenheimer S (2003): “Out of Eden”, Constable.

© Christopher Seddon 2009

Monday, 16 March 2009

Modern Human Behaviour

Anthropologists use the term modern human behaviour to refer to a list of behavioural traits that distinguish present day and recent anatomically-modern humans from earlier human species and possibly from earlier anatomically-modern humans. It is generally accepted that the “package” includes the use of abstract thought, symbolic behaviour (such as art and creative expression), use of syntactically-complex language and the ability to plan ahead, but there is no universally-agreed theoretical definition of what modern human behaviour actually is and there is considerable disagreement as to both when and how humans became behaviourally modern.

Trait lists:
Many researchers have adopted an empirical approach by drawing up a list of supposedly-modern traits and then seeking evidence of their emergence in the archaeological record. Henshilwood and Marean (2003) list the following traits as frequently viewed as evidence of modern human behaviour:

1. Burial of the dead as an indicator of ritual
2. Art, ornamentation, and decoration
3. Symbolic use of ochre
4. Worked bone and antler
5. Blade technology
6. Standardization of artifact types
7. Artifact diversity
8. Complex hearth construction
9. Organized use of domestic space
10. Expanded exchange networks
11. Effective large-mammal exploitation
12. Seasonally focused mobility strategies
13. Use of harsh environments
14. Fishing and fowling

The problem, as they point out, with this approach, is that even genuine evidence of absence of many of these traits does not preclude behavioural modernity as other environmental factors could also be responsible, making certain activities problematic or simply unnecessary.

A possible definition:
Henshilwood and Marean define modern human behaviour as “behaviour that is mediated by socially constructed patterns of symbolic thinking, actions, and communication that allow for material and information exchange and cultural continuity between and across generations and contemporaneous communities.” All extant humans are thus defined as modern by the ability to store or display data external to the human brain, rather than by their technology itself. The key criterion for modern human behaviour is not the capacity for symbolic thought but the use of symbolism to organize behaviour.

The distinction between capacity and actual use is important because the capacity for an action doesn’t mean it will necessarily happen immediately: behaviourally-modern humans clearly had the capacity for aeroplanes, mobile phones and the internet long before these things actually appeared.

Henshilwood and Marean believe that the term “modern human behaviour” should be replaced with “fully symbolic sapiens behaviour” and regard it as the culmination of a long line of developments toward modernity; the point at which it is to be recognized archaeologically being when artefacts or features carry a clear symbolic message that is exosomatic (i.e. recorded outside the brain) such as art, ornaments or decoration. Even the earliest behaviourally-modern societies should have been able to transmit arbitrary systems of beliefs and innovations, resulting in identifiable evidence of symbolism in the archaeological record.

Big Bang versus Gradualism:
There are two main views concerning the origins of modern human behaviour. The Big Bang or Great Leap Forward model views it as a single punctuated event, though opinions vary as to when it happened. Richard Klein sees it happening about 50,000 years ago, possibly as the result of a genetic mutation, but at all events long after the appearance of the first anatomically-modern humans around 200,000 years ago (Klein, 1999; Klein & Edgar, 2002). Other proponents include Jared Diamond and Steven Mithen (Diamond, 1991; Mithen, 1996).

However this view is disputed by others including Stephen Oppenheimer, Robert Foley, Sally McBrearty and Alison S. Brooks, who claim there was no “big bang” and knowledge, skills and culture gradually developed over hundreds of millennia (see Oppenheimer, 2003; Lewin & Foley, 2004; McBrearty & Brooks, 2000; McBrearty, 2007).

Evidence for the Big Bang:
What the Big Bang theory is in essence saying is that while humans who were living in Africa around 200,000 years ago might have resembled people living today, but cognitively they weren’t quite “with it” and to us would have appeared simple-minded. On the face of it, this would seem to be an odd state of affairs. Why would people with brains comparable in size to our own lack our mental capabilities?

Until fairly recently, the archaeological evidence did seem to suggest that this was indeed the case. Support for a “great leap forward” came from the Levant and from Europe.

The evidence from the Levant suggested the boundary between Neanderthals and modern humans fluctuated with environmental change, with Neanderthals moving east and south into the Levant with colder climates, while modern humans moved out of Africa into the Levant with warmer conditions. These fluctuations continued for tens of thousands of years until about 40,000 years ago, modern humans suddenly broke through the climate barrier and spread north and west into Europe. Within a comparatively short space of time the Neanderthals became extinct.

The archaeological record of Europe reveals an astonishing transformation from about 40,000 years ago, when the relatively crude tools of the Mousterian tradition are give way to the finely worked blade-based tools of the Upper Palaeolithic. Unequivocal evidence of artistic expression is seen for the first time in the form of beads, ornaments, figurines, carvings and the magnificent cave paintings at sites such as Chauvet, Cosquer and Lascaux.

It suggests to many a “human revolution”: the beginning of human culture: the arrival on the scene of modern Homo sapiens, fully-loaded and ready to roll. From Europe the revolution spread, eventually reaching all parts of the world. The Sistine Chapel, Shakespeare’s sonnets and Beethoven’s late stringed quartets all lay in the future, but it was on the steppes of Ice Age Europe that it all began.

Cognitive Fluidity:
But all of this begs the question: fully-modern humans are now thought to have appeared at least 200,000 years ago. If fully-modern behaviour didn’t appear until 50,000 years ago, as Klein believes, what was happening in the meantime – a matter of 150,000 years?

Steven Mithen, Professor of Archaeology at Reading University, believes that early humans, including early Homo sapiens, lacked what he refers to as “cognitive fluidity”.

In a theory first proposed in his 1996 book “The Prehistory of the Mind”, Mithen claims that the human brain originally had separate cognitive “domains” for different functions, such as social interaction, tool-making, food and resource gathering (“natural history”), etc. Modern human behaviour came about when the barriers between these domains broke down, allowing them to interact with each other. Art, religion and language all arose from the synergistic interactions between the various domains, but this was restricted to anatomically modern humans. Homo erectus and the Neanderthals quite literally never made the connection.

Mithen originally viewed “big bangs” occurring in different parts of the world at different times between 60,000-30,000 years ago, with the final leaps to full cognitive fluidity occurring by parallel evolution, though he has now revised his date for the emergence of cognitive fluidity to between 200,000-70,000 years ago, in Africa (Mithen, 1996 & 2007).

Mithen draws heavily on the work of Jerry Fodor, Annette Karmiloff-Smith, Michael Tomasello, Howard Gardiner, Leda Cosmides and John Tooby, but the idea of initially separate domains interacting may have been inspired in part by Julian Jaynes’ controversial theory about “bicameral minds”, proposed in 1976. (See Mithen, 1996; Fodor, 1983; Karmiloff-Smith, 1992; Tomasello, 1999; Gardiner, 1983 & 1999; Jaynes, 1976).

Mithen’s theory is well-argued and the existence of multiple intelligences in early humans is an intriguing possibility. Personally, though, I am somewhat sceptical as to whether anatomically-modern humans ever had this type of brain.

Stanford University’s Richard Klein is a long-time supporter of the Big Bang theory. Unlike many “big bangers” Klein does present a specific biological case for the emergence of modern human behaviour. His original “prime suspect” for the genetic mutation leading to modern human behaviour was a gene known as FOXP2, or forkhead box P2, which regulates a number of other genes, some of which are believed to play a role in the development of the parts of the brain associated with speech, although the exact genes involved are not known. The FOXP2 gene is not unique to humans, but exists with very few differences in other animals.

The first clue that FOXP2 might be a “speech gene” came from studies of Family KE, an extended British family living in London (their actual identity is not in the public domain). Some members of the family have problems with aspects of grammar, including the use of inflexions for marking tense. They also have difficulty in producing the fine movements of the tongue and lips required for normal speech. The problem affects three generations of the family and has been studied since the 1990s. In 2001 geneticists determined that the affected members of the family all have a defective version of the FOXP2 gene.

In 2002 a team led by Wolfgang Enard at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany compared the human version of the FOXP2 gene with that of the chimpanzee, gorilla, orang-utan, rhesus macaque and mouse. They found that the gene is highly conserved, with differences of just three amino acid positions out of around 700 between the human version and the mouse version. But curiously two of these changes had occurred since the split between humans and chimps, a far more recent occurrence than the split between humans and mice. They suggested that these two changes might be critical to speech and language. The beneficial mutation has been positively selected for by natural selection and they estimated that it had become fixed in the human population at some stage in the last 200,000 years (Enard et al, 2002).

Klein believed the actual date would be 50,000 years, and that FOXP2 was the “smoking gun” responsible for the Great Leap Forward. But even a date of 200,000 years would rule out behavioural modernity in the Neanderthals, who had diverged from Homo sapiens much earlier.

Then in 2007 came a complete volte-face from the Max Planck Institute. The sequencing of the Neanderthal genome had revealed that Neanderthals possessed exactly the same version of FOXP2 as do modern humans (Krause et al, 2007). This not only pulled the rug from under Klein’s argument, it was also rather embarrassing for the group whose earlier 200,000 year estimate was now seen to be off by a factor of at least two. Dr. Svante Paabo, who was involved with both studies, admitted that the earlier estimates were “not flawed but rely on assumptions that are necessary but also universally known to be oversimplifications of the reality”.

Klein has nevertheless stuck to his guns. He said he was disappointed to have lost the genetic support from Paabo's work but had not changed his views. "The archaeological record suggests a major change in human behaviour 50,000 years ago," he said, "and I think there is overwhelming evidence for that" (quoted in the New York Times, 18 October 2007).

Has anybody thought of this?
There is for my mind a serious problem with the notion that a behaviourally-modern human brain could have achieved its present set of capabilities without any increase in size over the older model. We are in effect being asked to believe that while both early and present-day members of our own species had same brain-size, the version used by people today is far superior to that in use prior to 50,000 years ago.

Brains are very expensive things to run. In modern humans, they account for just 2% of our body weight, yet they take up 20% of the body’s energy-budget. Not only that giving birth to a large-brained infant poses considerable problems for women which are only partially-alleviated by human babies doing a considerable amount of their initial brain growth after birth, which in turn increased their postnatal dependency to a level way above that of other mammals (compare, for example, with a foal, which can literally hit the ground running).

Now consider the considerable increase in human brain size over that of apes. This occurred in two phases: firstly around 2.5 million years ago with the appearance of Homo habilis: and secondly around half a million years ago with the appearance of large-brained hominins such as Homo heidelbergensis. There is no doubt that these increases were driven by Darwinian selective pressure, meaning that the advantages of these larger brains outweighed the disadvantages as outlined above.

But the Big Bang theory implies that it is possible to increase brain-power by a few genetic tweaks, with no increase in actual size being necessary. This would surely give the best of both worlds – a small, fuel-efficient brain packing the same punch as a larger “gas guzzler”. If such a thing is possible, why didn’t it happen much earlier? Why did Homo habilis evolve a large, expensive-to-run brain rather than “tweaking” the smaller brain possessed by its australopithecine predecessors? The same argument could be applied to the second phase of brain expansion, 500,000 years ago.

But of course it didn’t happen that way: Nature took the apparently sub-optimal option of increasing physical brain size. This suggests to me that it wasn’t sub-optimal and was in fact the only available option for increasing brain-power.

If increasing brain-power without increasing brain-size was not possible for the first 2.5 million years of human evolution, how did it suddenly become possible 50,000 years ago?

Down with the Revolution:
In their seminal 2000 paper, Sally McBrearty and Alison Brooks suggest that the traditional interpretation of the archaeological record is seriously flawed:

“This view of events stems from a profound Eurocentric bias and a failure to appreciate the depth and breadth of the African archaeological record. In fact, many of the components of the ‘‘human revolution’’ claimed to appear at 40–50 ka are found in the African Middle Stone Age tens of thousands of years earlier.

These features include blade and microlithic technology, bone tools, increased geographic range, specialized hunting, the use of aquatic resources, long distance trade, systematic processing and use of pigment, and art and decoration. These items do not occur suddenly together as predicted by the ‘‘human revolution’’ model, but at sites that are widely separated in space and time. This suggests a gradual assembling of the package of modern human behaviours in Africa, and its later export to other regions of the Old World.” (McBrearty & Brooks, 2000).

McBrearty and Brooks claim that the “Big Bang” is in fact an illusion, arising from the fact that Europe has been studied archaeologically in far more depth than Africa, and that evidence of modern human behaviour can in fact be found in Africa that is far earlier than any seen for Europe. This is of course exactly what one would expect to find if Homo sapiens evolved in Africa and only later migrated to Africa.

The paper presents evidence for the gradual acquisition of the elements of so-called modern human behaviour over the course of 300,000 years:

Images: 40k
Beads: 60k
Microliths: 65k
Notational pieces (incised): 100k
Mining: 100k
Barbed points: 100k
Bone tools: 100k
Fishing: 110k
Long-distance exchange: 140k
Shellfishing: 140k
Points: 300k
Pigment processing: 300k
Grindstones: 300k
Blades: 300k

Four of the fourteen skills are present even before modern humans evolved and nearly all of the rest had appeared before the onset of the Upper Palaeolithic in Europe, where such technologies are associated with the supposed human revolution. While there is still not conclusive evidence to dismiss the "Big Bang" theory, my feeling is that it is now on its way out.


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Christopher S. Henshilwood and Curtis W. Marean (2003): The Origin of Modern Human Behavior: Critique of the Models and Their Test Implications, Current Anthropology Volume 44, Number 5, December 2003.

Jaynes J (1976): “The Origin of Consciousness in the Breakdown of the Bicameral Mind”, Mariner Books, USA.

Karmiloff-Smith A (1992): “Beyond Modularity”, MIT Press, Cambridge, MA.

Klein, R. (1999): The Human Career (2nd Edition), University of Chicago Press.

Klein R & Edgar B (2002): “The Dawn of Human Culture”, John Wiley & Sons Inc., New York.

Lewin, R and Foley, R (2004): Principles of Human Evolution (2nd edition), Blackwell Science Ltd.

McBrearty S (2007): “Down with the Revolution”, Macdonald Institute Monographs.

McBrearty S & Brooks A (2000): The revolution that wasn’t: a new
interpretation of the origin of modern human behaviour, Journal of Human Evolution (2000) 39, 453–563.

Mellars P, Boyle K, Bar-Yosef O & Stringer C (eds.) (2007): Rethinking the human revolution, Macdonald Institute Monographs.

Mithen S (1996): “The Prehistory of the Mind”, Thames & Hudson.

Mithen S (2005): The Singing Neanderthal, Weidenfeld & Nicholson.

Oppenheimer S (2002): “Out of Eden”, Constable.

Tomasello (1999): “The Cultural Origins of Human Cognition”, Harvard University Press, Cambridge, MA & London.

© Christopher Seddon 2009

Saturday, 14 March 2009

Unusual coins from Austria

Issued by the Munze Osterreich (Austrian Mint), this pair of bimetallic coins feature metals not normally associated with currency. The left hand coin is a pre-Euro 100 Schilling denomination, struck in 2000 to mark the Millennium. The right hand coin was struck in 2008 with a face value of 25 Euro and is entitled “Faszination Licht” (fascination of light). Both coins are 40mm in diameter and are comprised of an outer ring of 90% fine silver. The inner “plug” of the left hand coin is titanium; that of the right hand coin is niobium.

Titanium was discovered by the Cornish mineralogist William Gregor in 1791 and later named by the German chemist Martin Heinrich Klaproth for the Titans of Greek mythology. It is often referred to as “high tech”, “space age” etc on account of its combination of low density, high tensile strength and resistance to corrosion, which makes it ideal for a very wide range of applications in the aeorospace and other industries. Accordingly it seemed an appropriate choice of metal for use in the 100 Schilling coin which was struck as Austria’s contribution to a world-wide series of Millennium coins which all had at least one unusual feature (others featured unusual shapes, denominations, etc.).

The coin’s reverse features a computer chip ringed by the words “Republik Osterreich 100 Schilling”. The obverse features a world map with the words “Millennium 2000” ringed by electrical pylons, atoms, planets and other symbols of a high-tech age.

(The 21st Century of course did not actually begin until 1 January 2001.)

Niobium is a transitional metal named for Niobe, the daughter of Tantalus. The metal is always found in association with the metal Tantalum, with which it shares many properties. Tantalum was named for Tantalus because when placed in acid it did not “take up” the acid, i.e. react with it. (In Greek mythology Tantalus was punished by the gods by being placed in a pool of water, which always receded when he tried to drink from it.) Niobium is used to alloy steel and in superconductors and has recently become popular in tinted forms in jewellery. Although fairly expensive, Niobium is not considered to be a precious metal.

The Austrian Mint began issuing silver/niobium 25 Euro coins in 2003. Each year the niobium “plug” has been tinted a different colour. The 2008 coin is a celebration of light and commemorates the Austrian inventor Carl Auer von Welsbach, whose inventions included the “flints” used in lighters, the mantles used in 19th Century gas-lighting, and the metal-filament light bulb which was an improvement on Edison’s carbon-filament.

The coin’s obverse features a lamp-lighter in front of the Vienna City Hall.
The reverse has a partial portrait of Welsbach. The green niobium pill portrays the shining sun and several methods of illumination from the gas light through electric light bulbs, neon lights, LEDs etc are featured on the silver ring.

In common with other commemorative coins issued within the Eurozone, the coin is not legal tender outside its country of issue, i.e. Austria.

© Christopher Seddon 2009

Sunday, 8 March 2009

Klasies River Caves

The Klasies River Caves are a complex of five caves located to the east of the Klasies River mouth in Eastern Cape Province, on the Tsitsikama coast of South Africa. The caves show evidence of occupation by anatomically modern humans dating from 125,000 years ago. They share a common stratigraphic sequence up to 16m deep which reveals further occupations around 110,000 years ago; 90,000 years ago and 60,000 years ago. These dates have been obtained by Electron Spin Resonance (ESR) and luminescence dating methods.

The caves have been excavated since the 1960s. They form an important source of information about the African Middle Stone Age (MSA) (250,000-40,000 years ago). Quantities of hearth ash, shell, animal bones and human remains have been recovered in association with MSA industries. From the base upwards, these have been associated with sub-phases MSA I, MSA II, Howison’s Poort and MSA III.

The Howieson’s Poort lithics were apparently used as hafted elements in a composite toolkit. They were made from non-local raw materials either obtained by people ranging far afield or long-distance trade. All of these things are suggestive of modern human behaviour, once believed to have only emerged much later.

The animal assemblages include small terrestrial vertebrates, larger herbivores, fish and shellfish. The latter are present in deep accumulations, suggesting extensive exploitation. Some of the human remains show cutmarks suggestive of cannibalism.

In 1998, the South African Provincial Heritage Committee proposed the caves as a UNESCO World Heritage Site. The caves were inscribed on the Heritage List in December 1999.


Conroy G (1997): “Reconstructing Human Origins: A Modern Synthesis”, W.W. Norton & Co. Inc, New York, NY & London.

Scarre C (2005) (Ed): “The human past”, Thames & Hudson.

© Christopher Seddon 2009

Saturday, 7 March 2009

Gantry at Deptford Creek

Taken on a fine day in July 2005.

© Christopher Seddon 2009

Monday, 2 March 2009


In 1965, as the space race between the United States and the Soviet Union was hotting up, officials at NASA realised that they did not have “space rated” wristwatch that could be used for the upcoming Project Gemini. Given that the program was slated to include an EVA or space walk, there was an obvious need for a watch that could withstand exposure to vacuum and other rigours of spaceflight. In addition to being able to keep good time under such conditions, the watch would have to incorporate a chronograph or stop-watch function, so astronauts could see at a glance how long they had spent outside their spacecraft and to help carry out other tasks that required accurate timing.

Rather than go through the time consuming procedure of inviting bids for a “space watch”, NASA decided to send a couple of engineers to out to downtown Houston with instructions to procure a variety of off-the-shelf chronographs for testing. The tests included exposure to extreme temperatures, vacuum, intense humidity, shock, acceleration, pressure and vibration. At the end of the tests, NASA had a clear winner as the watch most suitable for spaceflight: the Omega Speedmaster.

The Speedmaster was first introduced by in 1957 and utilised the Lemania 2310 (AKA Omega 321) manual-wind movement. It is often stated that NASA specified a manual-wind movement because they thought automatic (“self-winding”) movements would not function in zero-gravity conditions, but this is incorrect on two counts. Firstly an automatic works by inertia and is not dependent on gravity; secondly the simple reason NASA selected a manual-wind chronograph is that at the time that was the only type available. The first automatic chronograph movement – the Zenith el Primero – did not come into use until near the end of the decade. However it is likely that in the cramped conditions of a Gemini or Apollo spacecraft, there would be insufficient activity to keep an automatic fully wound and a manual-wind would be more suitable.

On 3 June 1965, Gemini 4 pilot Edward White became the first US astronaut to make a spacewalk. He was wearing an Omega Speedmaster, strapped to the outside of his spacesuit with a Velcro strap. Curiously it was not until almost a year later that Omega finally learned the use to which NASA had been putting their watches. As might be expected, they wasted little time in cashing in and photographs of White’s spacewalk were soon featuring in their advertising literature. The watch itself was renamed the Speedmaster Professional, but its finest hour was yet to come.

Early on the morning of 21 July 1969, Buzz Aldrin stepped out onto the surface of the Moon wearing a Speedmaster Professional, which thus became the first watch to be worn on the Moon. Earlier, Neil Armstrong had had to leave his own watch in the Eagle lunar module after the lander’s onboard chronometer developed a malfunction. Sadly this historic watch was later stolen while on loan to the Smithsonian and has never been recovered.

In April the following year a Speedmaster Professional was used to time a crucial engine burn aboard the crippled Apollo XIII during the desperate and ultimately successful endeavour to return the spacecraft safely to Earth.

Meanwhile feeling was growing that an American watch should be used on NASA moon missions and the US-owned Bulova company lobbied the White House for their watches to be used instead of the “Speedy Pro”. Eventually NASA was persuaded to test a fresh batch of watches, including a specially-manufactured Bulova chronograph, but the Omega again came out on top with the Bulova stopping several times during testing.

By now, not only NASA was equipping its astronauts with the Speedmaster Professional. In 1975, when an Apollo spacecraft rendezvoused with a Soviet Soyuz in Earth orbit, both crews were wearing what had by now become known as the Moonwatch.

In 1978 NASA held a fresh series of tests ahead of the Space Shuttle program. Once again the Speedmaster Professional triumphed. The watch had by now received an updated movement, the Lemania 1873 (AKA Omega 861), which featured a shuttle/cam system rather than a column-wheel. The former design is simpler and thus is cheaper to both manufacture and service, but it yields nothing in terms of performance and reliability. The 1873 is again a manual-wind movement.

Externally however the Speedmaster Professional has changed very little in over half a century, even retaining its old-fashioned Hessalite (plexiglass) crystal in preference to a modern scratch-resistant sapphire crystal. This has been at the request of NASA. Plexiglass scratches quite easily, but it is virtually indestructible. By contrast, a sharp blow can shatter a sapphire crystal. Having sapphire fragments floating about inside the zero-g environment of a spacecraft is obviously not a good idea! A sapphire version, also featuring a sapphire display back, is available at extra cost but many enthusiasts prefer the Hessalite model, which is the only flight-qualified version.

The Speedy Pro is certainly not the only watch to go into space (and was probably not even the only watch worn on the Moon – contra Omega’s website), but even now it is the only watch permitted to be used for EVAs from the International Space Station or from the Space Shuttle. The Casio G-Shock – a watch almost as iconic as the Speedy – is routinely worn aboard the ISS, but because their batteries may explode in a vacuum, they cannot be used for spacewalking.

Who knows, the Omega Speedmaster Professional may even eventually become known as the Marswatch.

© Christopher Seddon 2009

Sunday, 1 March 2009


Inspired by the Soviet photographer Alexander Rodchenko, these photographs were taken in Newcastle and Gateshead in November 2006.

© Christopher Seddon 2009