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From: How to Use Your Mind

Though most people understand more or less vaguely that the brain acts
in some way during study, exact knowledge of the nature of this action
is not general. As you will be greatly assisted in understanding mental
processes by such knowledge, we shall briefly examine the brain and its
connections. It will be manifestly impossible to inquire into its
nature very minutely, but by means of a description you will be able to
secure some conception of it and thus will be able better to control
the mental processes which it underlies.

To the naked eye the brain is a large jelly-like mass enclosed in a
bony covering, about one-fourth of an inch thick, called the skull.
Inside the skull it is protected by a thick membrane. At its base
emerges the spinal cord, a long strand of nerve fibers extending down
the spine. For most of its length, the cord is about as large around as
your little finger, but it tapers at the lower end. From it at right
angles throughout its length branch out thirty-one pairs of fibrous
nerves which radiate to all parts of the body. The brain and spinal
cord, with all its ramifications, are known as the nervous system. You
see now that, though we started with the statement that the mind is
intimately connected with the brain, we must now enlarge our statement
and say it is connected with the entire nervous system. It is therefore
to the nervous system that we must turn our attention.

Although to the naked eye the nervous system is apparently made up of a
number of different kinds of material, still we see, when we turn our
microscopes upon it, that its parts are structurally the same. Reduced
to lowest terms, the nervous system is found to be composed of minute
units of structure called nerve-cells or neurones. Each of these looks
like a string frayed out at both ends, with a bulge somewhere along its
length. The nervous system is made up of millions of these little cells
packed together in various combinations and distributed throughout the
body. Some of the neurones are as long as three feet; others measure
but a fraction of an inch in length.

We do not know exactly how the mind, that part of us which feels,
reasons and wills, is connected with this mass of cells called the
nervous system. We do know, however, that every time anything occurs in
the mind, there is a change in some part of the nervous system.
Applying this fact to study, it is obvious that when you are performing
any of the operations of study, memorizing foreign vocabularies, making
arithmetical calculations, reasoning out problems in geometry, you are
making changes in your nervous system. The question before us, then,
is, What is the nature of these changes?

According to present knowledge, the action of the nervous system is
best conceived as a form of chemical change that spreads among the
nerve-cells. We call this commotion the nervous current. It is very
rapid, moving faster than one hundred feet a second, and runs along the
cells in much the same way as a "spark runs along a train of
gunpowder." It is important to note that neurones never act singly;
they always act in groups, the nervous current passing from neurone to
neurone. It is thought that the most important changes in the nervous
system do not occur within the individual neurones, but at the points
where they join with each other. This point of connection is called the
synapse and although we do not understand its exact nature, it may well
be pictured as a valve that governs the passage of the nervous current
from neurone to neurone. At time of birth, most of the valves are
closed. Only a few are open, mainly those connected with the vegetative
processes such as breathing and digestion. But as the individual is
played upon by the objects of the environment, the valves open to the
passage of the nervous current. With increased use they become more and
more permeable, and thus learning is the process of making easier the
passage of the nervous current from one neurone to another.

We shall secure further light upon the action of the nervous system if
we examine some of the properties belonging to nerve-cells. The first
one is _impressibility_. Nerve-cells are very sensitive to impressions
from the outside. If you have ever had the dentist touch an exposed
nerve, you know how extreme this sensitivity is. Naturally such a
property is very important in education, for had we not the power to
receive impressions from the outside world we should not be able to
acquire knowledge. We should not even be able to perceive danger and
remove ourselves from harm. "If we compare a man's body to a building,
calling the steel frame-work his skeleton and the furnace and power
station his digestive organs and lungs, the nervous system would
include, with other things, the thermometers, heat regulators, electric
buttons, door-bells, valve-openers,--the parts of the building, in
short, which are specifically designed to respond to influences of the
environment." The second property of nerve-cells which is important in
study is _conductivity_. As soon as a neurone is stimulated at one end,
it communicates its excitement, by means of the nervous current, to the
next neurone or to neighboring neurones. Just as an electric current
might pass along one wire, thence to another, and along it to a third,
so the nervous current passes from neurone to neurone. As might be
expected, the two functions of impressibility and conductivity are
aided by such an arrangement of the nerve-cells that the nervous
current may pass over definitely laid pathways. These systems of
pathways will be described in a later paragraph.

The third property of nerve-cells which is important in study is
_modifiability_. That is, impressions made upon the nerve-cells are
retained. Most living tissue is modifiable to some extent. The features
of the face are modifiable, and if one habitually assumes a peevish
expression, it becomes, after a time, permanently fixed. The nervous
system, however, possesses the power of modifiability to a marked
degree, even a single impression sufficing to make striking
modification. This is very important in study, being the basis for the
retentive powers of the mind.

Having examined the action of the nervous system in its simplicity, we
have now to examine the ways in which the parts of the nervous system
are combined. We shall be helped if we keep to the conception of it as
an aggregation of systems or groups of pathways. Some of these we shall
attempt to trace out. Beginning with those at the outermost parts of
the body, we find them located in the sense-organs, not only within
the traditional five, but also within the muscles, tendons, joints,
and internal organs of the body such as the heart, and digestive
organs. In all these places we find ends of neurones which converge at
the spinal cord and travel to the brain. They are called sensory
neurones and their function is to carry messages inward to the brain.
Thus, the brain represents, in great part, a central receiving station
for impressions from the outside world. The nerve-cells carrying
messages from the various parts of the body terminate in particular
areas. Thus an area in the back part of the brain receives messages
from the eyes; another area near the top of the brain receives messages
from the skin. These areas are quite clearly marked out and may be
studied in detail by means of the accompanying diagram.

There is another large group of nerve-cells which, when traced out, are
found to have one terminal in the brain and the other in the muscles
throughout the body. The area in the brain, where these neurones
emerge, is near the top of the brain in the area marked _Motor_ on the
diagram. From here the fibers travel down through the spinal cord and
out to the muscles. The nerve-cells in this group are called motor
neurones and their function is to carry messages from the brain out to
the muscles, for a muscle ordinarily does not act without a nervous
current to set it off.

So far we have seen that the brain has the two functions of receiving
impressions from the sense-organs and of sending out orders to the
muscles. There is a further mechanism that must now be described. When
messages are received in the sensory areas, it is necessary that there
be some means within the brain of transmitting them over to the motor
area so that they may be acted upon. Such an arrangement is provided by
another group of nerve-cells in the brain, having as their function the
transmission of the nervous current from one area to another. They are
called association neurones and transmit the nervous current from
sensory areas to motor areas or from one sensory area to another. For
example, suppose you see a brick falling from above and you dodge
quickly back. The neural action accompanying this occurrence consists
of an impression upon the nerve-cells in the eye, the conduction of the
nervous current back to the visual area of the brain, the transmission
of the current over association neurones to the motor area, then its
transmission over the motor neurones, down the spinal cord, to the
muscles that enable you to dodge the missile. The association neurones
have the further function of connecting one sensory area in the brain
with another. For example, when you see, smell, taste and touch an
orange, the corresponding areas in the brain act in conjunction and are
associated by means of the association neurones connecting them. The
association neurones play a large part in the securing and organizing
of knowledge. They are very important in study, for all learning
consists in building up associations.

From the foregoing description we see that the nervous system consists
merely of a mechanism for the reception and transmission of incoming
messages and their transformation into outgoing messages which produce
movement. The brain is the center where such transformations are made,
being a sort of central switchboard which permits the sense-organs to
come into communication with muscles. It is also the instrument by
means of which the impressions from the various senses can be united
and experience can be unified. The brain serves further as the medium
whereby impressions once made can be retained. That is, it is the great
organ of memory. Hence we see that it is to this organ we must look for
the performance of the activities necessary to study. Everything that
enters it produces some modification within it. Education consists in a
process of undergoing a selected group of experiences of such a nature
as to leave beneficial results in the brain. By means of the changes
made there, the individual is able better to adjust himself to new
situations. For when the individual enters the world, he is not
prepared to meet many situations; only a few of the neural connections
are made and he is able to perform only a meagre number of simple acts,
such as breathing, crying, digestion. The pathways for complex acts,
such as speaking English or French, or writing, are not formed at birth
but must be built up within the life-time of the individual. It is the
process of building them up that we call education. This process is a
physical feat involving the production of changes in physical material
in the brain. Study involves the overcoming of resistance in the
nervous system. That is why it is so hard. In your early school-days,
when you set about laboriously learning the multiplication table, your
unwilling protests were wrung because you were being compelled to force
the nervous current through new pathways, and to overcome the inertia
of physical matter. Today, when you begin a train of reasoning, the
task is difficult because you are opening hitherto untravelled
pathways. There is a comforting thought, however, which is derived from
the factor of modifiability, in that with each succeeding repetition,
the task becomes easier, because the path becomes worn smoothly and the
nervous current seeks it of its own accord; in other words, each act
and each thought tends to become habitualized. Education is then a
process of forming habits, and the rest of the book will be devoted to
the description and discussion of habits which a student should form.


Reading: Herrick (7)

Exercise 1. Draw a picture of the brain, showing roughly what takes
place there (a) when you read a book, (6) listen to a lecture, (c) take



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