Masters of the Planet (35 page)

As if in riposte to the findings at Pinnacle Point, the latest report from Blombos indicates that, around 75 thousand years ago, the people there were also exhibiting advanced technological prowess. For not only have fire-hardened silcrete tools now been confirmed at Blombos, but it's recognized that their edges had been improved by an approach called pressure flaking: a delicate technique that is otherwise known only after about 20 thousand years ago in Europe, where it was the work of late Cro-Magnons. This unexpected finding is pretty amazing, but it does make it much easier to believe a reported date of around 90 thousand
years
for some bone harpoons found at a site called Katanda in the Eastern Congo. This is many tens of thousands years than the earliest previously known barbed harpoons, made by Cro-Magnons in Europe well after the appearance there of pressure flaking. Evidence is thus beginning to pile up very impressively that something really important was astir in Africa during the middle and later phases of the MSA.

Exactly who the southern MSA people were remains a conundrum. They do not seem to have practiced burial at or near their living places, so few of their bones have been preserved. Several isolated teeth from Pinnacle Point are not very informative, but one notable exception to the lack of human fossils in association with the MSA occurs at the caves of the Klasies River Mouth, a couple hundred miles east along the coast from Blombos. In MSA levels at Klasies, archaeologists found evidence for a symbolic division of the living space into distinct functional areas by over 100 thousand years ago; and at 80 to 90 thousand years ago, some highly fragmentary human remains were discovered that may represent the cooked remnants of a cannibal feast. The remains themselves have usually been interpreted as those of
Homo sapiens;
and if they do not fall precisely within the envelope of variation shown by our species today, they are certainly very close.

Following all the excitement of Blombos times, the symbolic trail cools a bit. A few MSA sites in southern and eastern Africa have produced fragments of ostrich eggshell bearing what seem to be deliberately incised patterns. Such pieces are most numerous at South Africa's Diepkloof rock shelter. At 60 thousand years or so, this site is a bit later than Blombos, but it is still firmly in the MSA. The fragments seem to have originally formed part of water containers decorated with symbolic motifs, and they convincingly confirm an ongoing South African symbolic tradition during the later part of the MSA. Ostrich eggshell was also used as a material for symbolic artifacts at East African sites, though later in time. The best-known such locality is Enkapune Ya Muto (EKP) rock shelter, in the Kenyan Rift Valley. EKP is dated to about 40 thousand years ago, which places it at the local point of transition from the MSA to the Late Stone Age (LSA). The LSA is a period of African prehistory that originated at around the same time the Upper Paleolithic arrived in Europe, and the two are considered broadly equivalent; as far as we
can
tell, the LSA was the work everywhere of fully modern humans. The EKP ostrich shell objects are unengraved but beautifully shaped disks that were strung as beads; so they differ in category from the decorated containers from Diepkloof. Nonetheless, some cultural continuity with the South African LSA may be hinted at by similar beads found at South African LSA sites.

Africa is a very large continent, vast tracts of which are
terra incognita
to Paleolithic archaeologists. It is thus particularly frustrating that, apart from such tantalizing finds such as those from Katanda, we really don't have much of a clue as to what was happening midcontinent in the symbolic domain, at the time when hominids both in the far north and the far south were showing those intriguing signs of dawning modernity in their ways of dealing with the world. How much indirect contact there may have been between human populations in the north and south of Africa during the later MSA has to remain largely conjectural, as does just how much those populations may have been differentiated biologically from each other. The fact that
Nassarius
shells were the chosen bead-making objects early on in both regions is suggestive, but perhaps not a lot more than that. During the wet phase 120 thousand years ago the dramatic ecological barrier that nowadays separates the northern fringes of the African continent from its sub-Saharan south really didn't exist, and it is not unreasonable to suppose that in a period of awakening symbolic awareness, regular trading routes crossed what has now become the hyperarid Sahara. But during the following MIS 4 the desert reasserted itself as a formidable barrier, at least intermittently; and by the time that we find those intriguing hints of a new cognitive style around 80 thousand years ago, it is by no means clear that routine cultural and biological interchange would have been possible, except maybe via the Nile Valley.

Still, if the molecular anthropologists are right (and they are backed up by the archaeological record, as far as it goes), the cognitively modern humans who eventually took over the world originated in an eastern African population, probably a rather small one, that very likely lived
after
Blombos times. It is also probably relevant in this respect that, not long after the spurt of symbolic innovation between 80 and 60 thousand years ago, southern Africa was plunged into a prolonged period
of
drought during which its interior became largely depopulated. Under these conditions it is surely only moderately likely, at best, that the cultural practices of the Blombos and Pinnacle Point people were directly antecedent to later expressions of similar kind farther to the north. It seems far more likely that there was a quickening of the creative hominid spirit in a variety of places during the later part of the MSA, capitalizing everywhere on a general predisposition toward symbolic thinking that had been born rather earlier, with the origin of
Homo sapiens
as a hugely distinctive physical entity at some time after the MSA had begun.

Wherever in Africa the population ancestral to all living humans emerged, and whatever route its descendants took during their exodus, it is clear that cognitively modern humans had made their appearance in Eurasia by not long after 60 thousand years ago, at latest. We've seen that humans were in Australia by around 50 thousand years ago; and they were leaving traces of artistic activity there not long thereafter. Sites in southern India that may also be in this date range yield stone tools remarkably similar to those that were produced at sites in southern and eastern Africa at places such as Blombos, Diepkloof, and EKP; and at one of them fragments of ostrich eggshell have been found that bear cross-hatched motifs similar to those from Blombos and Diepkloof. Most remarkably of all, we have evidence both from the physical remains and the art of the Cro-Magnons that people with an entirely full-blown modern sensibility had arrived in Europe, a relatively remote and inaccessible peninsula, soon after we begin to find the presence of shell beads at early Upper Paleolithic sites in Lebanon and Turkey. This evidence dates to over 40 thousand years ago and confirms that Cro-Magnon predecessors were already spreading north and west by that time.

The Cro-Magnons have left us all the evidence we could possibly need that they were people cognitively like us. Yet the fact that we have this proof of the Cro-Magnons' cognitive attainments is largely an accident of both cultural expression and topography. Decorating the dank and dangerous depths of caves with fabulous animal images and a whole vocabulary of geometrical symbols is, to put it mildly, a rather unusual pursuit; and while all historically documented human societies have clearly been symbolic, few others have expressed this capacity in so durable a way. What's more, most Cro-Magnon art was preserved in caves
and
crannies in the limestone landscapes these people just happened to inhabit; in other geological settings we might not expect parallel expressions to be preserved. Still, the accident is a happy one indeed, and it certainly gives us a minimum date for the attainment of fully modern consciousness.

Some scholars have suggested that the dazzling Cro-Magnon art represented such a break with the past that a recent genetic modification must have been acquired in the Cro-Magnons' lineage to make all this creativity possible: a modification whose effects were confined to their neural information processing, and were not reflected in the fossil bones which are all the physical evidence we have of them. But biologically this seems less plausible than other possibilities; and the hints from Blombos and Pinnacle Point give us excellent reason to believe that the symbolic sensibility, of which Cro-Magnon art was the finest and most exhaustive early expression, was already initially astir much earlier in human history. Beyond this, there really is no reason whatever to think that the earliest possessors of the cognitive capacity that underwrites this sensibility should have discovered all of its dimensions at once. Indeed, the subsequent technological and economic histories of humankind have been virtually synonymous with the exploration of this relatively newfound capacity. And we are still groping toward its invisible limits today.

FOURTEEN

IN THE BEGINNING WAS THE WORD

In biological terms the birth of anatomical
Homo sapiens,
maybe as much as a hundred thousand years before the first
Nassarius
bead was ever pierced, was a huge event. We differ from our closest known relatives in numerous features of the skull and of the postcranial skeleton, in important features of brain growth, and almost certainly in critical features of internal brain organization as well. These differences exist on an unusual scale. At least to the human eye, most primate species don't differ very much from their closest relatives. Differences tend to be largely in external features such as coat color, or ear size, or even just in vocalizations; and variations in bony structure tend to be minor. In contrast, and even allowing for the poor record we have of our close extinct kin,
Homo sapiens
appears as distinctive and unprecedented. Still, we evidently came by our unusual anatomical structure and capacities very recently: there is certainly no evidence to support the notion that we gradually became who we inherently are over an extended period, in either the physical or the intellectual sense. As I have already observed, this suggests that the physical origin of our species lay in a short-term event of major developmental reorganization, even if that event was likely driven by a rather minor structural innovation at the DNA level. Such an occurrence is made more plausible by the
fact
that genetic innovations of the kind that probably produced us are most likely to become “fixed” (i.e., the norm) in small and genetically isolated populations, such as those into which climatic vagaries would regularly have fragmented our already thinly spread African forebears. In other words, conditions in the late Pleistocene would have been as propitious as you could imagine for the kind of event that would necessarily have had to underwrite the appearance of a creature as unusual as ourselves.

As far as we know,
Homo sapiens
is totally unique in significantly expressing an ability to manipulate information symbolically. And understanding how we acquired this capacity is fundamental to any complete understanding of ourselves. Some possibilities we can eliminate right away. To begin with, our novel way of dealing with information was hardly a predictable outcome of any identifiable trend that preceded it. And neither was it simply a threshold effect of acquiring a greater and greater brain volume over vast spans of time, as smarter individuals outreproduced dumber ones in our ancestral lineage. We know this not only because the nonsymbolic Neanderthals had brains that were on average larger than ours, but because our own brains appear to have shrunk by as much as ten percent since Cro-Magnon times, and we haven't slipped below the symbolic threshold yet. Whatever you want to make of this latter tidbit, it is at the very least evident that we have to look to more than simple increase in brain mass to explain our unusual cognitive style.

The only evident alternative is that our strange intellectual faculty is attributable to a novel neural conformation, a change in the internal organization and wiring of our brains. Acquisition of such a novelty would not in itself be unprecedented; after all, the human brain has a long and largely accretionary history going right back to the earliest vertebrate brains half a billion years ago—and beyond. Nothing inherently new there. But the
results
of this acquisition were revolutionary: in today's jargon, they were “emergent,” whereby an adventitious change or addition to a pre-existing structure led to a whole new level of complexity in function.

Exactly when our amazing capability was initially acquired is something we cannot read directly from the fossil record: the paleoneurologists, those specialists who specialize in the form of fossil brains as
determined
from the impressions they leave inside the cranial vault, cannot even agree in principle if there is any functional significance to the minor external shape differences we see between modern human and Neanderthal brains. All we know for sure, from the archaeological evidence, is that the two species
behaved
differently. The Neanderthals seem to have possessed a sophisticated version of the “old-style” hominid way of dealing with stimuli, using purely intuitive processes. In contrast, we symbolic
Homo sapiens
are processing information in an entirely revolutionary and unprecedented way, even though the “old” brain is still very much there, deep inside.

GENES, LANGUAGE, AND LARYNXES

I mentioned briefly that some believe our new way of doing business is due to the very recent acquisition of a “symbolic” gene. Excitement about this possibility ran high after scientists discovered that the human version of a gene called FOXP2 was intimately involved in our language abilities, at least to the extent that people possessing a mutated form are unable to speak properly (though they don't seem to be more broadly cognitively impaired). Imaging studies showed that such people have reduced activity in Broca's area of the brain. The excitement increased yet further when various Neanderthals were shown to have possessed the normal human version of the FOXP2 gene, sparking speculation that here was proof that the Neanderthals had possessed language. If this speculation had been on the mark, it would have been huge in its implications for complex consciousness; for language is a supremely symbolic system that depends on the creation and manipulation of mental symbols for its very existence. Any organism able to generate language would almost certainly have been capable of exhibiting all of the other correlates of symbolic thought. But if only it were that simple: it turns out that numerous genes (all of them working as they should) are involved in determining normal language and speech production in humans. Indeed, so many genes are intimately choreographed in the developmental process that sometimes it seems a miracle that any of us ever develops normally. In view of all this it is evident that the notion of a single gene “for” language (even a regulating gene, like FOXP2) is an
illusion,
albeit an attractive one. What the Neanderthals possessed was a necessary condition for language, but it wasn't sufficient.