Re: Human language (long)
Phillip Bigelow (bh162@scn.org)
Fri, 10 Jan 1997 21:34:17 -0800
John A. Halloran wrote:
>
> In article <32D5ADF8.22E@scn.org> Phillip Bigelow <bh162@scn.org> writes:
> >The problem with this idea is that in extant animals that hunt in packs
> >(canids, for instance), they possess a *non*-"descended" larynx.
> >There is really no need for a "descended" larynx for long-range
> >oral communication. In fact, the plesiomorphic condition of
> >the carnivoran larynx makes it *advantageous* for increased
> >volume with an associated higher pitch. In humans, the relaxed
> >laryngeal structure has made it possible to produce
> >a wider range of pitches (including intermediate pitches that many
> >other animals cannot reproduce), but it also incurred a cost
> >(slightly less volume, when compared to carnivorans that obligatively
> >communicate long distances (such as canids)).
>
> Thanks for jumping in here. Canids seem to achieve a high volume with
> explosive barks and long howls.
Exactly. Their vocal tracts are well adapted for this ability.
Coincidentally, though (and a point that you seem to miss)
is that the hyal bone arrangement in canids is essentially
a plesiomorphy shared by many other members of the
Mammalia; it is not a specialization.
> What special adaptations do their vocal
> tracts have to produce this volume? Michael has brought up the primate
> example of the howler monkey, which had to evolve an enlarged, hollow hyoid to
> act as a resonating chamber for its long-distance calls.
I am interested in this particular case. I have never read of any
taxa possessing hollow hyal bones. If someone knows of a reference
that describes this osteology, I would love to get it.
>Would it have been
> possible for primates to evolve the vocal apparatus that canids possess?
It is important to remember at this point in the discussion that
the "vocal tract" or "vocal apparatus" (comprising soft tissues *and*
bones) is distinctly different from the *fossilized* remains from this
region of the throat (i.e., only the ossified elements of the
hyoid apparatus). A lot of conclusions can be drawn from
analyzing just the hyal bones, but to get *really* detailed about
the evolution of speech...well...it just ain't going to happen
by studying just the fossil hyal bones.
>It
> is a fact that canid vocalizing is part and parcel of their lifestyle, a
> lifestyle that primates evolving into hominids began to adopt.
I'm not sure I follow. Where is the data to support this contention?
> >> The main factor in language as in speech or talking is the brain, not
> >> the vocal tract.
> > Are you claiming that the enlarged hominid brain
> >evolved prior to the re-arrangement of the laryngeal/pharyngeal
> >structure? If so, what evidence do you know of that supports this
> >order of development?
> I think that the vocal tract preadapted itself to language for nonlinguistic
> reasons.
This could very well be the case. There is some *semi*-analogous
research literature that deals with this topic. In the case of
two closely-related extant species of sloth (Bradypus and Choleopus),
both the hyal apparatus AND the associated hyoid soft tissues of
the two animals are significantly different.
The reason for this morphological difference was attributed
to *slightly* different feeding styles between the two species of
sloth.
Virginia Naples, PhD published this work about 15 years ago in
the _Journal of Mammology_.
> I also think that the brain preadapted itself to language for
> nonlinguistic reasons, for which I am quite willing to adopt the
> missile-throwing theories of William H. Calvin. I would then point to the
> trend over the last 10,000 years which has involved expansion of the temporal
> lobes of the brain at the expense of the parietal lobes.
Last 10,000 years? Are you sure that this isn't just a statistical
artifact in a generally-sparce fossil dataset? For instance, what about
the possibility that one is sampling (unknowingly) different
ethnic groups, rather than sampling a time-change in temporal
lobe dimmensions in one group of fossils?
I guess I am dubius of your point.
> Language
> comprehension is located in the temporal lobes. This trend is called
> brachycephalization.
Not to purposefully throw a wrench into a well-oiled machine, but:
Bonobo chimpanzees (such as the research subject "Kansi") have
excellent human language *comprehension* (roughly approximating
the human language comprehension of a 6 year-old human).
> "The best documented but least well understood case of recent
> evolution has been the increasing brachycephalization of the species."
> Frederick S. Hulse, The Human Species (New York, 1963), p. 400.
How can one be so certain of the purported relationship between
degree of brachycephalization and the level of comprehension
of complex language? (Particularly, taking into consideration the
example <above> of the small-brained Bonobo chimpanzee having
nearly a complete understanding of human speech).
As one of the Georgia researchers who is involved in the "Kansi"
study said, "If Kansi had the vocal morphology to *talk* like a human,
we could have a conversation equivalent to conversing with a
6 year-old." (I believe that quote is attributed to Dr. Rumbaugh,
herself).
> "One of the most baffling and precipitous phyletic trends in
> Homo Sapiens has been the appreciable shortening and moderate
> widening of the head." Edward E. Hunt, Jr. "The Continuing
> Evolution of Modern Man," Cold Spring Harbor Symposia on
> Quantitative Biology, 24 (1959): 250.
I am very unimpressed with interpretations of such relationships.
Two problems:
1) Emphasis is placed on one species (no inter-species
comparisons between communicative ability and cortex dimmensions).
and;
2) How can a *reliable* correlation be made between larger
cortex size and a level of speech advancement? Is there any
reliable data in the journals on this?
As to what I mean by this statement, I advise reading
(or re-reading) Steven Jay Gould's book _The Mismeasure of Man_.
<pb>
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