Sunday, July 10, 2005

Did Neanderthals stutter?

I am currently reading about the Neanderthal people in a book on human evolution. They are a human species that died out some 20'000 years ago, and co-existed with Modern Humans. I am wondering whether they stuttered, too! :-) I am sure some of them did, too. As my old physics professor used to say: "What can happen, will happen!". If they have speech and it can break down, it will break down in some people. What I am really interested in is whether there were a higher proportion of people who stuttered? Maybe they died out, because they were all stutterers. Stuttering is not helpful while hunting. Just imagine, a Neanderthal warning others:" Thhhheerrrrreee is a bbbbbbbbear". Well then it's definitely too late!

But seriously, maybe Modern Humans in the past or other human species were stuttering more. And then they got selected out by nature. So what I mean is the following. If you have two kinds of humans with different genes, the one stutters and the other doesnt. Then the group who doesnt stutter might have more off-spring for various reasons social exclusion, greater difficulties in influencing others, etc. Even if the difference is just 0.1% per generation, after 1'000 generation the trait will be eliminated.

The question really is how did speech arise? Apes for example they make sounds but they dont speak. Sometime along human evolution, the brain must have evolved to integrate inner thinking into speech (sequence of sounds with grammatical rules). So the ability to speak must have some evolutionary advantage, and thus the inability is a disadvantage. This disadvantage is greater the more complex the society I would guess? So if we now only see 1% of the population stuttering, it might be that 100'000 years ago ist was 10% or 20%. If the selection is harsher in societies, we should expect to see a higher proportion of stuttering in Aborigenes or the people from isolated Indonesian islands. Is this true?? Does anyone have data on this?

This could lead to the conclusion that stuttering or PDS is not really a disorder as such, but the remainder of what the brain in speech areas in early human being were. I always knew that I had some deep deep animalistic roots... :-)

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