From: Ramez Naam (mez@apexnano.com)
Date: Wed Apr 16 2003 - 10:18:11 MDT
From: Christian Weisgerber [mailto:naddy@mips.inka.de]
> Ramez Naam <mez@apexnano.com> wrote:
>
> > I'm using the common conjecture that grammatical language
> > arose around 40,000 years ago and fueled the "great leap
> > forward".
>
> Huh? In what circles is this a common conjecture?
> Has anybody bothered to tell the linguists?
This is common in anthropological circles. It is also held by many
linguists. For an example of a linguist agreement with this
conjecture, see
http://www.esat.kuleuven.ac.be/~compi/pub/spoken_language/ch1.pdf
> > You're right that there is no firm proof that this was when
> > grammatical language arose, but the circumstantial evidence
> > appears to have convinced most anthropologists.
>
> I'd love to know what this circumstantial evidence is.
There's evidence from both anthropology and genetics.
1) 40 - 50,000 years ago there is a sudden shift in human culture. At
that time we very suddenly see:
- The widespread appearance of art. This is the first real evidence
for symbolic thinking in humans. Prior to about 40,000 years ago,
there is no archeological evidence of symbolic thinking.
- The design of the first complex (multi-part) tools.
- The first /reproduced/ tool designs. Prior to this point each stone
or bone tool we find is fairly idiosyncratic. After about 50k years
ago we suddenly find many tools built from several pieces and in the
exact same way.
- A noticeable increase in life expectancy.
All of these lead us to believe that human culture of this time took a
large step upwards. It appeared to support more complex memes (art,
more complex tools), to suddenly allow the transmission of memes from
individual to individual with higher accuracy (many tools built to
same design), and to provide greater protection of the tribe against
external threats (increased life expectancy).
2) Prior to this 40-50k point, Europe and Asia were peopled by
Neanderthals.
- Neanderthals were physically much tougher than cro-magnon men (our
ancestors). Neanderthal brains were as large as cro-magnon brains.
So prima facia, we'd expect Neanderthals to compete with and perhaps
out-compete Cro-Magnons.
- However, within a very short timespan after the first evidence of
cro-magnon man in Africa, they had spread to the farthest corners of
Europe and Asia. What's more, while cro-magnon man flourished,
Neanderthals /went extinct/. And, while there is still a bit of
controversy over this, the consensus among both geneticists and
anthropologists is the Cro-Magnons and Neanderthals did not cross
breed.
3) Relevant to the cross-breeding issue is this observation: In modern
humans, when a technologically superior culture has come in contact
with a technologically inferior culture a wide variety of outcomes
ensue. In some cases the tech inferior population is wiped out. More
frequently, the tech inferior culture assimilates the technology of
the tech superior culture. For example, agriculture was developed
independently about half a dozen times in human history, but spread to
a few thousand different cultures.
However, /this never happened between Cro-Magnons and Neanderthals!/
Neanderthals never adopted the superior technology of cro-magnon man.
This suggests that they were in some way unable. The specific
suggestion here is that they lacked the power of speech necessary for
the effective transmission of these technological memes.
4) From the genetic side, we have the emergence of the FOXP2 gene.
Mutations in FOXP2 in humans result in a variety of severe speech
deficits. Virtually all mammals, including other primates, share an
earlier, non-human version of FOXP2 which is not compatible with
spoken language. The modern version that we humans have arose fairly
recently. Population genetic studies put the cap on when this arose
at about 200,000 years. This doesn't prove the 40,000 number, but
puts something of an upper bound on how long ago human speech could
have arisen. Specifically, it suggests that modern language abilities
were not around at the dawn of homo sapiens half a million years ago.
Put this all together and you don't have an ironclad case, but it's
rather suggestive that /something/ important in human symbolic
thinking and meme-processing and meme-communicating ability happened
around 40k - 50k years ago. Language is a pretty good fit for that
something.
cheers,
mez
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