Genes, Brains, and Human Potential The Science and Ideology of Intelligence

INTELLIGENT DEVELOPMENT 157

of hype and publicity mentioned in chapter 1, these parents are mostly

convinced that the potential for desirable qualities like intelligence, or

special talent of some sort, resides and varies in the genes. And they think

of it as already residing in the egg, in that homunculus state mentioned

earlier.

As we have already seen, though, what is assumed to be ge ne tic is really

the manifestation of a whole developmental system. So, with the excep-

tion of rare disorders, the anxiety is prob ably unwarranted. And there is

certainly no test for the ge ne tic potential of eggs or sperm from diff er ent

individuals, however much the idea inspires the pipe dreams of some

behavioral ge ne ticists.

INTERIM SUMMARY

So far this chapter has dealt with development in multicellular organisms.
Th e general message is that development itself is an intelligent pro cess, not
a fi xed program. It generates almost incredible variation of form and
function on the basis of structural information gathered from internal
and external environments. Developmental pro cesses among cells also
incorporate and regulate the intelligent systems within them, adding
a new level to a regulatory hierarchy. It all ensures that functional poten-
tials are not merely expressed; they are made.
Some developmental systems provide plasticity throughout life. But
they remain limited in their speeds of response to change. Other intelli-
gent systems— physiology, brains, be hav ior and cognition— are needed to
deal with more rapid environmental changes. Th e emergence of such in-
telligent systems has been the most signifi cant and exciting manifestation
of evolution, though it is oft en overlooked as such. Th e rest of this chap-
ter deals with the fi rst of these systems.

PHYSIOLOGY

Intelligent developmental systems ensure that the myriad diff er ent cells

diff erentiate and fi nd their proper places, at the right times, in a whole

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