Masters of the Planet (34 page)

Apart from those early and unsophisticated émigrés in Israel, we do not have any clear
Homo sapiens
fossils from anywhere outside Africa earlier than the molecular evidence suggests we should find them. A fragmentary mandible some 100 thousand years old from the cave of Zhirendong in southern China has recently been touted as that of a
Homo sapiens;
but its features actually group it most plainly with the endemic “Peking Man”
Homo erectus,
rather than with any potential early modern invaders. Broadly, the molecules indicate that in the period following about 60 thousand years ago, as the rigors of MIS 4 were giving way to the kinder conditions of MIS 3, the bearers of several African DNA lineages left the parent continent. The first principal migration was via Asia Minor into India, whence a coastal route was followed into southeast Asia. All this happened quickly: as we know from archaeological evidence, humans were in Australia by at least 50 thousand years ago. This is all the more remarkable because the first Australians must have crossed at least 50 miles of open ocean to reach their new home: a feat that would have required not only boats—or at least, sophisticated rafts—but excellent navigational skills as well.

Meanwhile, one branch of the migrants continued down into southeast Asia, and another went north to colonize China and Mongolia, eventually doubling back into Central Asia. Migrants of African origin reached Europe, presumably via Asia Minor, by about 40 thousand years ago; and even as climatic conditions were descending to the trough of the last glacial period some 21 thousand years ago, modern people had ventured as far as northern Siberia, above the Arctic Circle. The extraordinary extent of this culturally enabled achievement, involving
as
it did survival in some of the most difficult conditions the world has to offer, is emphasized by the fact that the supposedly cold-adapted Neanderthals had tended to shun such environments by hundreds of miles.

The process that led to the modern human takeover of the Old World—and later of the New World and the Pacific—was not, of course, one of deliberate expeditioneering. Humans almost certainly expanded their ranges largely by simple demographic spread, as populations grew and budded off new groups into new territories. Of course, as local conditions fluctuated, the process would neither have been regular nor inexorable. Tiny populations were certainly washed back and forth by constant climatic and demographic vicissitudes, with numerous local expansions and extinctions. But this didn't mean that on balance human spread could not occur rapidly: if a human population expanded its range by only ten miles in a generation, this would add up to more than 1,500 miles in a mere 2,500 years, something quite feasible on the time-scale involved. Whatever the details, though, just in itself population growth on this scale implies that there was something
different
about these new migrants: namely, an unprecedented ability to intensify their exploitation of the environments around them. This fed back into growing populations, and consequently into further geographical expansion.

This demographic difference is also implicit in the fact that the new
Homo sapiens
was not moving into territory that was virgin for hominids: related species almost certainly already resided in many if not most of the regions into which it expanded. And the larger pattern their encounters took is clear. When behaviorally modern humans moved into Europe, the behaviorally archaic Neanderthals yielded. When they moved into southern Asia it was
Homo erectus,
which flourished equally late in its last southeast Asian island redoubt, that promptly disappeared. The same went, a little later in time, for those unfortunate Hobbits of Flores; and probably also in poorly documented Africa for any other hominids that may have survived the rigors of MIS 4. There was clearly something
special
about the new invaders. From the very beginning of hominid history, the world had typically supported several different kinds of hominid at one time—sometimes several of them on the very same landscape. In striking contrast, once behaviorally modern
humans
had emerged from Africa the world rapidly became a hominid monoculture. This is surely telling us something very important about ourselves: thoughtlessly or otherwise, we are not only entirely intolerant of competition, but uniquely equipped to express and impose that intolerance. It's something we might do well to bear in mind as we continue energetically persecuting our closest surviving relatives into extinction.

THIRTEEN

THE ORIGIN OF SYMBOLIC BEHAVIOR

Our ancestors made an almost unimaginable transition from a non-symbolic, nonlinguistic way of processing and communicating information about the world to the symbolic and linguistic condition we enjoy today. It is a qualitative leap in cognitive state unparalleled in history. Indeed, as I've said, the only reason we have for believing that such a leap
could
ever have been made, is that it
was
made. And it seems to have been made well
after
the acquisition by our species of its distinctive modern biological form.

The earliest firm intimations we have that a symbolic sensibility was astir among populations of newly evolved
Homo sapiens
come from Africa or its immediate environs. The oldest of them are also a bit arguable, consisting principally of suggestions that at Skh
l, over 100 thousand years ago, small marine snail shells were already being pierced for stringing as beads, while lumps of pigment were heated, presumably to change their color from yellow into a more attractive orange or red. The shell beads are particularly interesting, because personal ornamentation using necklaces or bracelets (and, for that matter, bodily coloration using pigments) has usually had deep symbolic significance among historically documented peoples. How you dress and decorate yourself signifies your identity as a member of a group, or of a class or a profession or of an
age-cohort
within your group. Still, the early putative evidence for this kind of thing is slender at this point: two shells perforated (possibly by natural causes) through their weakest points at Skh
l, and a single shell at an Aterian site in Algeria of uncertain age. At both places, however, the shells were of a species that had to have been collected far away along the Mediterranean shore. This implies they were special objects to their possessors, specifically brought in through long-distance exchange. Possibly yet more significantly, at both sites the beads were made from the shells of a genus,
Nassarius,
that was widely used later on elsewhere in better-substantiated ornamental contexts.

Somewhat firmer bead evidence starts turning up at around the 80-thousand-year point at other Aterian sites. Thus a dozen perforated
Nassarius
shells were found at the Moroccan Grotte des Pigeons. As at the Israeli and Algerian sites, this cave is far from the nearest possible source of the shells, which suggests that they had been deliberately brought in, probably through trade. But, again, there is as yet no definitive evidence that the holes in them were produced by human agency— though a few shells bore traces of pigment suggesting that they might have been deliberately colored, and showed a curious polish that may have come from rubbing against someone's skin.

Similar finds at other sites along the North African coast suggest that the Grotte des Pigeons findings were not isolated. But the best evidence suggesting that these North African manifestations were part of a larger pattern comes, oddly enough, from the opposite end of the African continent, some four thousand miles away. At Blombos Cave, a coastal site not far from the continent's southern tip, archaeologists found numerous perforated
Nassarius
shells that were worn in a way that strongly implies that they had been strung as beads. With a Middle Stone Age industrial context, and dating to about 76 thousand years ago, these beads were convincingly in the same general time range and broad cultural context as their North African equivalents, and their general acceptance as objects of personal adornment has made it look probable that some African MSA populations, at least, had begun to decorate their bodies in the period following about 100 thousand years ago.

But these people also left evidence of more explicitly symbolic behaviors. For Blombos has given us the earliest objects that we can confidently
interpret as symbolic. These come from the same Middle Stone Age levels that yielded the
Nassarius
beads, and they consist of a couple of ochre plaques several inches long, on each of which a deliberately smoothed surface displays a distinctly engraved cross-hatched pattern. What the pattern was intended to convey we may never know; but the two pieces were found several vertical inches apart in the deposits, suggesting that this geometric pattern was a consistent one that retained its meaning over time, and didn't simply represent a single individual's idle doodlings. Another piece of ochre, found at a rock shelter some 250 miles away and possibly created only fractionally later in time, bears what may be a simplified version of the same motif, providing yet more evidence that the pattern contained meaning. What's more, in the same deposits at Blombos were found bone tools, probably originally hafted, of the kind that are so conspicuously missing from the Neanderthals' contemporary tool kits in Europe.

Not too far from Blombos is another coastal cave complex, at Pinnacle Point. This was also inhabited by MSA humans, beginning around 164 thousand years ago and continuing with hiatuses (possibly because high sea levels washed out intervening deposits during MIS 5e) until well under 70 thousand years ago. At the 164-thousand-year point, occupants of these caves were already expanding their diet to incorporate hard-to-obtain marine resources, possibly in response to the cold climatic conditions of MIS 6. At the same time, they were regularly processing
pigments
and producing “bladelets”—small stone flakes that were sunk into handles, the likes of which were not seen outside of Africa until very much later. This was clearly a time of significant cultural change, though it is arguable that any of these technological expressions was
necessarily
a harbinger of symbolic cognition.

One of the geometrically engraved ochre plaques from Blombos Cave on the southern African coast. Around 77,000 years old, this piece is the earliest evidently symbolic object. Drawing by Patricia Wynne.

Still, while I've already claimed that there is very little in Old Stone Age technology that we can take as
prima facie
evidence of the workings of symbolic minds, if there is an exception to this rule we find it at Pinnacle Point. Good materials for stoneworking are pretty rare in the area; and there is good evidence that by around 72 thousand years ago the people who stayed there were using complex technology to improve at least one of the indifferent raw materials available to them: silcrete, a type of rock that occasionally forms in silica-rich soils. Silcrete is suitable for flaking by stone tool makers, but in its natural state it doesn't hold an edge for long. However, the Pinnacle Point people discovered that, if it is appropriately heated and cooled in an elaborate series of steps, silcrete hardens and makes much better tools. The technology involved is so complex, and involves so many stages of forward planning, that it could almost certainly never have been imagined and carried out by minds incapable of abstracting and visualizing long chains of cause and effect. So at 72 thousand years ago, right around the time when the Blombos people produced those symbolic plaques (but in an entirely different way), their Pinnacle Point neighbors were also exhibiting dawning symptoms of symbolic reasoning. Silcrete tools occur in the earlier levels of the Pinnacle Point complex as well, but at that more remote time the evidence is less good that the material from which they were made was deliberately heat-treated.