Sunday, October 9, 2011 - 0 comments

Once We are NOT Alone : 4. Competing Scenarios

By : Ian Tattersall

IN ALL THESE WAYS, early Upper Paleolithic people contrasted dramatically with the Neandertals. Some Neandertals in Europe seem to have picked up new ways of doing things from the arriving H. sapiens, but we have no direct clues as to the nature of the interaction between the two species. In light of the Neandertals’
rapid disappearance and of the appalling subsequent record of H.sapiens, though, we can reasonably surmise
that such interactions were rarely happy for the former. Certainly the repeated pattern found at archaeological
sites is one of short-term replacement, and there is no convincing biological evidence of any intermixing of peoples in Europe.

In the Levant, the coexistence ceased—after about 60,000 years or so—at right about the time that Upper Paleolithic– like tools began to appear. About 40,000 years ago the Neandertals of the Levant
yielded to a presumably culturally rich H. sapiens, just as their European counterparts had.

The key to the difference between the European and the Levantine scenarios lies, most probably, in the emergence of modern cognition—which, it is reasonable to assume, is equivalent to the advent
of symbolic thought. Business had continued more or less as usual right through the appearance of modern bone structure, and only later, with the acquisition of fully modern behavior patterns, did H. sapiens become completely intolerant of competition from its nearest—and, evidently, not its dearest—co-inhabitors.

To understand how this change in sensibility occurred, we have to recall certain things about the evolutionary process. First, as in this case, all innovations must necessarily arise within preexisting species—for where else can they do so? Second, many novelties arise as “exaptations,” features acquired in one context before (often long before) being coopted in a different one. For example, hominids possessed essentially modern vocal tracts for hundreds of thousands of years before the behavioral record  gives us any reason to believe that they employed the articulate speech that the peculiar form of this tract permits.

And finally, it is important to bear in mind the phenomenon of emergence— the notion that a chance coincidence gives rise to something totally unexpected. The classic scientific example in this regard is water, whose properties are holly unpredicted by those of hydrogen and oxygen atoms alone. If we combine these various observations, we can see that, profound as the consequences of achieving symbolic thought may have been, the process whereby it came about was unexceptional .

We have no idea at present how the modern human brain converts a mass of electrical and chemical discharges into what we experience as consciousness. We do know, however, that somehow our lineage passed to symbolic thought from some nonsymbolic precursor state. The only plausible possibility is that
with the arrival of anatomically modern H. sapiens, existing exaptations were fortuitously linked by a relatively minor genetic innovation to create an unprecedented potential.

Yet even in principle this deduced scenario cannot be the full story, because anatomically modern humans behaved archaically for a long time before adopting modern behaviors. That discrepancy may be the result of the late appearance of some key hardwired innovation not reflected in the skeleton, which is all that fossilizes. But this seems unlikely, because it would have necessitated a wholesale Old World–wide replacement
of hominid populations in a very short time, something for which there is no evidence.

It is much more likely that the modern human capacity was born at—or close  to—the origin of H. sapiens, as an ability that lay fallow until it was activated by a cultural stimulus of some kind. If sufficiently advantageous, this behavioral novelty could then have spread rapidly by cultural contact among populations
that already had the potential to acquire it. No population replacement would have been necessary to spread the capability worldwide.

It is impossible to be sure what this innovation might have been, but the best current bet is that it was the invention of language. For language is not simply the medium by which we express our ideas and experiences to one another. Rather it is fundamental to the thought process itself. It involves categorizing and naming
objects and sensations in the outer and inner worlds and making associations between resulting mental symbols.

It is, in effect, impossible for us to conceive of thought (as we are familiar with it) in the absence of language, and it is the ability to form mental symbols that is the fount of our creativity. Only when  we are able to create such symbols can we recombine them and ask such questions as “What if...?”

We do not know exactly how language might have emerged in one local population of H. sapiens, although linguists have speculated widely. But we do know that a creature armed with symbolic skills is a formidable competitor— and not necessarily an entirely rational one, as the rest of the living world, including H. neanderthalensis, has discovered to its cost.

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Ian Tattersall was born in England and raised in East Africa. He is a curator in the department of anthropology at the American Museum of Natural History. His books include Becoming Human: Evolution and Human Uniqueness (Harvest Books, 1999) and The Last Neanderthal: The Rise, Success, and Mysterious Extinction of Our Closest Human Relatives (Westview Press, 1999, revised).


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