In studying the behaviour of animals, which is the only way of getting
at their mind, for it is only of our own mind that we have direct
knowledge, it is essential to give prominence to the fact that there has
been throughout the evolution of living creatures a strong tendency to
enregister or engrain capacities of doing things effectively. Thus
certain abilities come to be inborn; they are parts of the inheritance,
which will express themselves whenever the appropriate trigger is
pulled. The newly born child does not require to learn its breathing
movements, as it afterwards requires to learn its walking movements. The
ability to go through the breathing movements is inborn, engrained,
enregistered.
In other words, there are hereditary pre-arrangements of nerve-cells and
muscle-cells which come into activity almost as easily as the beating of
the heart. In a minute or two the newborn pigling creeps close to its
mother and sucks milk. It has not to learn how to do this any more than
we have to learn to cough or sneeze. Thus animals have many useful
ready-made, or almost ready-made, capacities of doing apparently clever
things. In simple cases of these inborn pre-arrangements we speak of
reflex actions; in more complicated cases, of instinctive behaviour. Now
the caution is this, that while these inborn capacities usually work
well in natural conditions, they sometimes work badly when the ordinary
routine is disturbed. We see this when a pigeon continues sitting for
many days on an empty nest, or when it fails to retrieve its eggs only
two inches away. But it would be a mistake to call the pigeon, because
of this, an unutterably stupid bird. We have only to think of the
achievements of homing pigeons to know that this cannot be true. We must
not judge animals in regard to those kinds of behaviour which have been
handed over to instinct, and go badly agee when the normal routine is
disturbed. In ninety-nine cases out of a hundred the enregistered
instinctive capacities work well, and the advantage of their becoming
stereotyped was to leave the animal more free for adventures at a higher
level. Being "a slave of instinct" may give the animal a security that
enables it to discover some new home or new food or new joy. Somewhat in
the same way, a man of methodical habits, which he has himself
established, may gain leisure to make some new departure of racial
profit.
[Illustration: _Photo: O. J. Wilkinson._