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Ray
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 Posted: Mon Oct 06, 2008 5:53 am Post subject: evolutionary adapation for speech production |
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Hi,
Rsearch has shown that some birds and primates produce formants (time-
varying acoustic energy bands) in their vocalizations by manipulating
the supralaryngeal vocal tract, a talent formerly thought to be
uniquely human. Does this constitute an argument against evolutionary
adapation for speech production in the human species?
I>d appreciate your help.
Ray |
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Entertained by my own EIM
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| Posted: Mon Oct 06, 2008 4:12 pm Post subject: Re: evolutionary adapation for speech production |
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"Ray" <raymondaliasapollyon@yahoo.com.tw> wrote in message
news:gcc95e$12ri$1@darwin.ediacara.org...
[quote]Hi,
Rsearch has shown that some birds and primates produce formants (time-
varying acoustic energy bands) in their vocalizations by manipulating
the supralaryngeal vocal tract, a talent formerly thought to be
uniquely human. Does this constitute an argument against evolutionary
adapation for speech production in the human species?
I>d appreciate your help.
Ray
[/quote]
No, it most certainly does not!
You will would have to look infinitely long and hard to find a physical,
chemical, physiological, phylogenetic or (even) an "experience plotting
type-collecting" argument for the impossibility of human speech -- in this
universe, that is.
;-) |
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Perplexed in Peoria
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| Posted: Wed Oct 08, 2008 4:07 pm Post subject: Re: evolutionary adapation for speech production |
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"Ray" <raymondaliasapollyon@yahoo.com.tw> wrote in message news:gcc95e$12ri$1@darwin.ediacara.org...
[quote]Hi,
Rsearch has shown that some birds and primates produce formants (time-
varying acoustic energy bands) in their vocalizations by manipulating
the supralaryngeal vocal tract, a talent formerly thought to be
uniquely human. Does this constitute an argument against evolutionary
adapation for speech production in the human species?
I>d appreciate your help.
[/quote]
I guess I don>t understand the question. To illustrate the reason I am
perplexed, consider this alternate question:
Research has shown that bats and some (now extinct) reptiles are capable
of flying, a talent formerly thought to be uniquely avian. Does this constitute
an argument against evolutionary adaptation for flight in the birds? |
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Lorentz
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| Posted: Wed Oct 08, 2008 4:07 pm Post subject: Re: evolutionary adapation for speech production |
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On Oct 6, 1:53=A0am, Ray <raymondaliasapoll...@yahoo.com.tw> wrote:
[quote]Hi,
Rsearch has shown that some birds and primates produce formants (time-
varying acoustic energy bands) in their vocalizations by manipulating
the supralaryngeal vocal tract, a talent formerly thought to be
uniquely human. Does this constitute an argument against evolutionary
adapation for speech production in the human species?
I>d appreciate your help.
Ray
[/quote]
Logically, it would strengthen the case for Darwinian evolution
provided the case wasn>t so strong already.
A common argument made against the evolution of any complex
capability is that since the historic sequence of events leading to
the capability is highly improbable because the intermediate features
leading to that capability do not increase fitness. In the case of
speech, the argument would be that since formants produced by the
supralaryngeal vocal tract have no adaptive value outside of speech,
the development of formant production by the supralaryngeal vocal
tract could not evolve.
However, you just said that some birds and primates have evolved
the capability to make formants by the supralaryngeal vocal tract is
used by both birds and primates. These birds and primates do not have
fully developed speech like human beings, yet they find the capability
of making formants useful, increasing their chance to survive and make
babies. So you can>t argue that this capability can>t be useful
outside of speech. However these creatures acquired it, the fact that
they have and use these formants shows that formants are useful for
their survival.
Some people would argue that the fact some birds make such
formants is not applicable to human speech, since the brains of birds
are so different from human beings. For instance, the argument would
go, birds have almost no grey matter. So maybe there is some unseen
law of nature that doesn>t permit both grey matter and supralaryngeal
formants evolving together in one species.
But you said some primates have can make supralaryngeal formants.
All primates have large amounts of grey matter, although most do not
have the high amounts human beings do. Some primates can not make
supralaryngeal formants, but have grey matter. And some primates have
a little grey matter, can make supralaryngeal formants, and can>t
speak. So there is no such law forbidding supralaryngeal formants and
grey matter arising independently of speech. Both features have uses
that have nothing to do with speech.
The people who would argue that speech evolved now have a
hypothetical mechanism for doing it. They can claim that for whatever
reason the primates and birds without speech use formants, the primate
ancestors of human beings could have started using it the same way.
There may be more than one hypothesis here, as each species may use
formants a different way. However, no one can argue that "half a vocal
tract" is useless without speech.
Two intermediate steps toward speech, grey matter and
supralaryngeal formants, have been shown to be useful independently of
each other. So the "half an eye" argument no longer applies to speech.
Not if what you said is true about primates and birds having
supralaryngeal formant vocalization. |
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