Simple v. complex systems

[from Jeff Vancouver 950919.1545]

Regarding Bruce A. and Bolles.

There is an interesting parallel here between control system investigation
and molecular genetics. In a recent article by Plomin in Current
Directions in psychological science (August, 1995). Plomin discusses the
work of the human genome project and the kinds of relationships one finds
between genes and phenotypes (usually disorders). Most of the work trys
for the simple one-gene, one-disorder hypothesis (OGOD). This has and can
work (e.g., PKU). But is not likely to work when the disorder (or
phenotype) is more complex. And I quote:

        "Looking for single genes for complex behaviors reminds me of the
old story of losing your wallet in a dark alley but looking for it under
the streetlamp because the light is better there." (p. 115)

Instead, complex behaviors are likely to emerge from 1) complex sets of
genes, and/or 2) interactions between genes and the environment. One of
the interesting aspects of this analogy is that weak (relatively low
correlations) associations between genes and behaviors are exciting
because they indicate progress toward identifying the set of genes, or the
gene that may be interacting with the environment. Thus, imperfect
control, not necessary of the level regarded as adequate, could indicate
one was on to something with regard to a control process, but that one
might need to hypotheses other systems as being involved as well.

Another variation of the OGOD hypothesis is that some complex disorder
(e.g., schizophrenia) is actually a variety of disorders, each with a
single gene associated with it. This is not unlike the situation of
multiple behaviors serving multiple goals.

Continuing to participate



                           Jeffrey B. Vancouver
Assistant Professor Phone: (212)998-7816
Department of Psychology Fax: (212)995-4018
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