The child, on the other hand, has an extremely long period of infancy, and
as a result, the nervous system is so plastic that it may be moulded,
fashioned and developed in almost any manner or direction, according to the
will of parents and the nature of the environment. The child, consequently,
may be educated. By education we mean the training and developing of
desirable instincts and capacities and the inhibiting of undesirable ones
so that the child may be able constantly to adjust himself to an
ever-changing environment.

Fiske, in "The Meaning of Infancy," Chapter 1, says: "The bird known as the
fly-catcher no sooner breaks the egg than it will snap at and catch a fly.
This action is not very simple, but because it is something the bird is
always doing, being indeed one of the very few things that this bird ever
does, the nervous connections needful for doing it are all established
before birth, and nothing but the presence of the fly is required to set
the operation going. With such creatures as the codfish, the turtle, or the
fly-catcher, there is nothing that can properly be called infancy. With
them, the sphere of education is extremely limited. They get their
education before they are born. In other words, heredity does everything
for them, education nothing.

"All mammals and most birds have a period of babyhood that is not very
long, but it is on the whole longer with the most intelligent creatures.
The period of helpfulness is a period of plasticity. The creature's career
is no longer exclusively determined by heredity. There is a period after
birth when its character can be slightly modified by what happens to it
after birth, that is, by its experience as an individual. It is no longer
necessary for each generation to be exactly like that which has preceded.
The door is opened through which the capacity for progress can enter.