9

DEPRIVATION AND DEVELOPMENT

Up to now we have been 
thinking of the brain as a fully 
formed, mature machine. We 
have been asking how it is 
connected, how the parts 
function in terms of everyday 
situations, and how they serve 
the interests of the animal. But 
that leaves untouched an 
entirely different and most 
important question: How did the 
machine get there in the first 
place?

    The problem has two major 
components. Much of the 
brain's development has to go 
on in the mother's uterus, 
before the animal is born. A 
glance at the brain of a 
newborn human tells us that 
although it has fewer creases 
and is somewhat smaller than 
the adult brain, it is otherwise 
not very different. But a glance 
can hardly tell us the whole 
story, because the baby is 
certainly not born knowing the 
alphabet or able to play tennis 
or the harp. All these 
accomplishments take 
training, and by training, we 
surely mean the molding or 
modification of neuronal 
circuits by environmental 
influences. The ultimate form 
of the brain, then, is a result of 
both prenatal and postnatal 
development. First, it involves 
a maturation that takes care of 
itself, depends on intrinsic 
properties of the organism, and 
occurs before or after the time 
at which birth happens to 
occur; second, it involves 
postnatal maturation that 
depends on instruction, 
training, education, learning, 
and experience--all more or 
less synonymous terms.