[net.sci] The neurodevelopment discussion, again

dorettas@iddic.UUCP (Doretta Schrock) (10/30/85)

> Perhaps, Mike, if you could repost your article that started this mini-debate
> this newsgroup may be pointed in an informative and intellectually satisfying
> direction, such that other readers (if any) might then be interested enough
> to actively participate.
> 
> 					Mark Stevans
> 					ritcv!husky!mls


Glad to oblige.  Here goes, as copied from my author_copy file:


Subject: Re: primate crying; language, reference articles [a little long :-]
Newsgroups: net.sci,net.kids
Distribution: net
References: <303@bcsaic.UUCP>

> We have an 8 week old baby boy who spends a certain amount of his
> time crying.  In one of the baby books it states that babies of this
> age cry about 3 hours a day.  I was wondering if other primates cry,
> and, if so, do they do it to the same degree.  If human babies cry
> to a greater extent this would give some support for the idea that
> crying is language preparation.
> 
> 	Doug Schuler

I believe (I can't find the book to be sure) that Jane Goodall relates
stories of gorillas and/or chimps crying, particularly in the case of an
infant in the group dying.  This would be crying in adult apes, not
infants, though.
Crying in humans is certainly used for communicative purposes from very
early on (as is smiling (no it isn't "gas" :-), etc.), though I don't know 
if you could call this language or language-like.  At 8 weeks a child is 
still neurologically immature, in terms of cerebral development, so their 
affective behavior is fairly limited.  There are (of course) about a zillion 
articles dealing with this sort of thing.  Since I'm already here, and since 
I have done a certain amount of reading in this area, I'm going to go ahead 
and plug my own favorite:
	"The Emergence of Emotions and the Development of Consciousness
	 In Infancy" in _The Psychobiology of Consciousness_ by C. Izard
	Edited by Davidson & Davidson (Plenum Press, NY 1980)
This is one of very few articles that encompasses nearly all the facets
of the development of consciousness in early childhood (environmental, 
neurological, genetic, etc.) and is still "correct" according to current 
theory.
  The only other *really* good paper I was able to find (in doing a review
for my own paper "The Neurological Correlates of the Emergence of 
Consciousness" (*ahem* :-)) is titled "The Neuropsychology of Development: 
Hemispheric Laterality, Limbic Language, and the Origin of Thought" by 
Rhawn Joseph (male? female? if anyone knows, please e-mail me!) in the 
Journal of Clinical Psychology, Vol 38 (1982), pp.5-30.  This is a pretty
theoretical article that further work will show to be more or less correct; 
it is nevertheless, a highly seminal work that deserves attention.  It
deals with the development of consciousness and the internal running monologue
as phenomena emerging from some specific attributes of cerebral development.
If you're up to it, a really excellent and wide-ranging view of consciousness.

Whew! My longest posting yet!

		Mike Sellers
		(soon to get a new net address, but this is good for now)
. . .

From postnews Mon Sep 30 13:20:34 1985
Subject: Re: ...what brain tells us about behavior (a little long)
Newsgroups: net.sci
Distribution: net

> >At 8 weeks a child is 
> >still neurologically immature, in terms of cerebral development, so their 
> >affective behavior is fairly limited.
> 
> It's not clear to me what is being said here.  Is someone proposing that the
> reason that young children are said to have limited affective behavior is
> because they lack what we call cerebral development?

I don't think that was my main point, though I guess my answer to your question
would be a partial "yes."  Children from pre-birth to about age 6 or 8 are in
the process of cerebral development.  The amount of activity falls off pretty
sharply after the first 18 to 24 months of infancy, however.  During this
time, there is a lot of developmental activity going on, primarily cortical 
cell growth, division, migration, myelination, and death (some areas of the 
brain lose up to 85% of their initial complement of neurons during early 
childhood (Cowan, Sci Am 1979)).  Barring somewhat extreme dualist/spiritualist
views, this state of dynamic growth (both in terms of numbers of neurons and
in numbers of synapses) must both affect and be affected by the child's type
and range of behavior.  There is much psychological research that has been done
(on animals) that show the cortical effects of differences in early 
environments, up to and including extreme visual impairment in the case of 
kittens who wore special glasses and whose brains did not develop the ability 
to distinguish vertical (or horizontal, depending upon the group) lines in the
environment.  Thus, an infant's brain is capable of a rather limited range
of actions and responses that gradually widens as the child gains experience
and develops neurally.

> What prevents us, having observed "limited affective behavior", and having
> established that it's specific to infants, from saying that we observe
> various sorts of limited development in infants, including the the sort we
> call "neurological"?  What is added to this account by saying that what
> explains the limited affective behavior is the neurologically immaturity?
> -- 
> 					-- Jon Krueger

If I understand your question (and I'm not sure that I do), it would seem
to have been answered above.  In addition, what would you propose as an
explanation of the rate and type of changes in infant behavior if not 
the development of the brain (primarily the cerebral cortex) and
nervous system?  Most of the other bodily systems (with the exception of
the reproductive system -- but most of us don't use that for determining
our behavior :-) are nearly fully developed at birth.  Nor can lack of
experience be the sole or main determinant, as otherwise the Skinnerian 
behaviorist models of language aquisition, etc., would have held up to 
observation and experimentation better than they have.  It is clear that
there are *both* developmental (as an expression of genetics) and 
environmental (i.e., experiential) components to the way a child's range,
type, and depth of behavior changes.  Attributing the locus of change
primarily to the nervous system would seem to simply be the most 
parsimonious theory that fits all the facts.

You might want to read the articles I suggested in my last posting,
or most anything by Pylyshyn.  A lot of William Cowan's work also focuses
on this sort of thing.

		-- Mike Sellers (note the name difference from above)
. . .

There it is.  Jon also mailed to me (are you out there, Jon?), saying that my
reply was "cogent" but that he was not totally convinced.  That was when the
dialogue broke down, so I'm not sure exactly what he meant.  I like the
"cogent" part, though.  Comments, anyone? (How about you folks dozing in the
back of the class, eh?)

	STILL waiting for my new address to come through (Yawn)
		Mike Sellers