Re: Indo-European question

Rik Roots wrote:
>
> > a) "Within a few generations" is most certainly not "overnight".
>
>In biological terms, it is. Assuming 20 years to a generation, and a
>possible timescale of, say, 100,000 years, then "a few generations"
>(let's say 5) equates to 0.1% of the timescale.
OK, but when I used the word for the first time in this discussion, I meant
it in a more "everyday" sense - within hours or at most a couple of days.
Even five generations is enough for some biological development to take
place.
>
>Personally, I lean towards the view that modern humans have been
>around for at least 500k years, and possibly more than 1m years
>(0.01-0.02%).
>
> > b) Human children are "predisposed" to learn language. This must, I'm
>led to
> > believe, mean that somewhere in the human genome there's something which
> > makes us acquire langauge during childhood. A such genetic adaption
>could,
> > in theory, indeed arise overnight (due to a mutation), but it wouldn't
>have
> > much effect until a reasonable porportion of the population had it. More
> > probably, this genetic mechanism consists of several mutations that
>occured
> > at different times and each one had an more or less immediate advantage
>for
> > the individual - that's how genetic adaptions usually work. Exactly
>where
> > along the line of development the acoustic communication became
>"langauge"
> > is, I guess, mostly a question of terminology (perhaps when the
> > phoneme-morpheme system was into place?).
> >
>That children have an innate ability to acquire language, and this
>ability is largely lost after the first dozen years or so, is accepted
>fact. The question is: where does this ability come from?
>
>I would argue that the purpose of the juvenile phase of any mammal's
>development is to acquire enough information to allow the mammal to
>survive and thrive in its environment. The brain is the organ used for
>this purpose, and it is arguable that much of the information gathered
>and stored is through a mechanism of pattern matching and cross
>referencing. This juvenile phase ends with the onset of sexual
>maturation, when other skills become more important.
>
>Now, there is an argument that a unique, defining difference between
>humans and apes is that humans delay the onset of sexual maturation by
>a significant period. This also increases the period allowed for
>information and skills gathering, and social development.
>
>Evolutionary development is not only about the rate of genetic
>mutation and survival of the fittest. It is also about using existing
>skills and abilities in novel ways to gain an advantage over competing
>species in a given ecological niche.
But the skills must've arisen at SOME time.
>
>And when genetic mutation is involved in a small, geographically
>discrete population, the effects of the mutation can spread through
>the population in a handful (3-4) of generations - spectacularly
>quick.
>
>So, what if - rather than recieving a magical gift, or a fortunate
>genetic mutation - humans were able to put an existing skill
>(information gathering, pattern matching and cross referencing in the
>brain) to a new use, such as the development of a sophisticated
>communication system. What if delaying sexual maturation allowed this
>to happen quickly?
>
>Certainly, understanding and using human language is a complex skill
>relying on whole reams of biological and neural systems. But delaying
>the onset of sexual maturation is a simple thing, principly delaying
>the release of the sex hormones testosterone, oestrogen, progesterone
>(and a few others) into the blood stream at the appropriate time. This
>(I believe) can be achieved through a small number of genetic
>mutations. And the change could be significant, for instance
>increasing the juvenile period from 2-3 years to 10-12 years at a
>stroke.
>
>This change would allow language skills to develop over the course of
>a few generations. Then natural selection can swing into force: a
>group of hominids capable of communicating and interacting effectively
>will survive longer and breed more effectively than similar hominids
>without this skill.
>
A complementing theory I've seen advanced alot recently is that speech was
perceived as "sexy" by the early hominids. Sexual selection can promote
"sexy" features very quickly.

>And this could happen time after time in separate lineages. A mutation
>that alters the vocal tract in some way to allow that hominid to be a
>better mimic (thus possibly a better hunter) could easily have
>happened 1-6 million years ago, and would quickly offer an
>evolutionary advantage.
Note that the advantage must've been reaonably large, as the reorganization
of the human vocal tract greatly increased the risk of choking to death. Our
vocal tracts are better suited to speaking that to eating!

>a genetic change in the neural network to
>accommodate better aural pattern matching and cross referencing could
>have extended a simple aural communication system from a dozen sounds
>to a couple of hundred sounds. Then a genetic change to delay the
>onset of puberty, thus allowing existing information gathering,
>pattern matching and cross referencing skills to be put to a new use -
>the development of a complex language - could have led to a cascade
>effect of rapid evolutionary development and an exponential
>(or greater) explosion in numbers of the lucky population(s) where it
>happened.
>
>In effect, language maketh man.
>
>I'm not saying this is the way it happened. I'm just offering a
>hypothesis of how it could have happened. And at least this hypothesis
>can be tested and challenged, through the study of evolution in other
>species, and developments in the ever-burgeoning fields of brain and
>cognitive studies, etc.
>
> >                                                        Andreas
>
>Rik, knee deep.
                                                           Andreas
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