tuba@ur-tut.UUCP (Jon Krueger) (11/18/85)
Mike, thanks for re-posting your original article, along with quotes from relevant articles that followed. Permit me to summarize: Mike Sellers wrote: >>>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, its >>>affective behavior is fairly limited. I (Jon Krueger) wrote: >>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? Mike Sellers replied: >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 [Mike names some brain and >CNS structures, and provides development periods]. 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. [Mike notes some >experiments] 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. My comment now: Mike, it's interesting that you name some experiments which show differing [visual] environments generating different behavior. You seem to be saying that the change in behavior is due to a change in brain. But what failed to develop normally was the organism's visual system. It's quite possible that the change in environment also produced a change in brain. It may be that the brain is more responsible for the aspects of vision in question than the organism's peripheral sense organs or motor functions. But we aren't permitted to assume that. The researchers didn't change brains, they changed environments. They produced a chage in behavior. The brain is at best an indirect factor, which you might posit between environment and behavior. Later in my first posting, I (Jon Krueger) wrote >>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? Mike writes: >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? My comment now: As a rule, I don't try to explain a phenomenon until I can establish it. This saves me the trouble of accounting for things that never happened. For instance, I've never felt I had to explain why Libras are better athletes than Taurus people. Some people say it's true, but they never have any data on the subject. Before I explain a change in affective behavior, I want some way of measuring affective behavior. During our discussion, Mike cited some literature, none of which would appear to tell me how to go about measuring affective behavior. Is there a way? Can two labs measure the same behavior and come out with the same numbers? If not, nothing needs explaining. Can you even define "affective behavior" so I know when I'm looking at it? Suppose I tell you that my affective behavior detect-o-matic (detects affects while you watch) is on the fritz, and the vendor refuses to admit it's broken. He claims it's my PC interface, not his machine. How would we go about proving to him that his machine is dead? Mike also writes: >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. My comment: Skinner's model doesn't require special brain structures to explain language development. A good refutation of his model would be discovery of such structures. You could then validate the discovery by developing techniques whereby properties of such structures could predict properties of language acquisition. For instance, statements like "Bob's more articulate than Bill because Bob's brain differs from Bill's in the following ways". This is the kind of observation and experimentation that would refute Skinner. Can you cite references to it? By the way, Skinner gives a technology whereby we can make Bill more articulate. Is there a brain technology to do this? Mike also writes: >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 of change primarily to the nervous system would seem to simply be >the most parsimonious theory that fits all the facts. I reply: Yes, there are both, and I sure hope this doesn't degenerate into a nature-nurture discussion. I'm more interested in what makes good science. My kind of parsimony generates predictions that can be tested experimentally. It's easier to define and manipulate independant variables in the environment than in the genetic endowment. Genetic engineering may someday change this, but I suspect not within my lifetime. Human behavior that's determined by the human genetic endownment represents millions of years of environments acting on behavior (presumably by selecting for survival or reproduction). Most of that history is inaccessible to us. By contrast, human behavior that's determined by the environment represents behavior under control of factors in the present time, factors the experimenter can manipulate. I expect more predictions about behavior to be made and tested from researchers who use the tools available to them.