dorettas@iddic.UUCP (Doretta Schrock) (09/30/85)
> >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)