PERCEPTION
No young child at first sees objects as we see them, or hears sounds as
we hear them. This power, the power of perception, is a gradual
development. It grows day by day out of the learner's experience in his
world of sights and sounds, and whatever other fields his senses respond
to.
1. THE FUNCTION OF PERCEPTION
NEED OF KNOWING THE MATERIAL WORLD.--It is the business of perception to
give us knowledge of our world of material _objects_ and their relations
in _space_ and _time_. The material world which we enter through the
gateways of the senses is more marvelous by far than any fairy world
created by the fancy of story-tellers; for it contains the elements of
all they have conceived and much more besides. It is more marvelous than
any structure planned and executed by the mind of man; for all the
wonders and beauties of the Coliseum or of St. Peter's existed in nature
before they were discovered by the architect and thrown together in
those magnificent structures. The material advancement of civilization
has been but the discovery of the objects, forces, and laws of nature,
and their use in inventions serviceable to men. And these forces and
laws of nature were discovered only as they were made manifest through
objects in the material world.
The problem lying before each individual who would enter fully into this
rich world of environment, then, is to discover at first hand just as
large a part of the material world about him as possible. In the most
humble environment of the most uneventful life is to be found the
material for discoveries and inventions yet undreamed of. Lying in the
shade of an apple tree under the open sky, Newton read from a falling
apple the fundamental principles of the law of gravitation which has
revolutionized science; sitting at a humble tea table Watt watched the
gurgling of the steam escaping from the kettle, and evolved the steam
engine therefrom; with his simple kite, Franklin drew down the lightning
from the clouds, and started the science of electricity; through
studying a ball, the ancient scholars conceived the earth to be a
sphere, and Columbus discovered America.
THE PROBLEM WHICH CONFRONTS THE CHILD.--Well it is that the child,
starting his life's journey, cannot see the magnitude of the task before
him. Cast amid a world of objects of whose very existence he is
ignorant, and whose meaning and uses have to be learned by slow and
often painful experience, he proceeds step by step through the senses in
his discovery of the objects about him. Yet, considered again, we
ourselves are after all but a step in advance of the child. Though we
are somewhat more familiar with the use of our senses than he, and know
a few more objects about us, yet the knowledge of the wisest of us is at
best pitifully meager compared with the richness of nature. So
impossible is it for us to know all our material environment, that men
have taken to becoming specialists. One man will spend his life in the
study of a certain variety of plants, while there are hundreds of
thousands of varieties all about him; another will study a particular
kind of animal life, perhaps too minute to be seen with the naked eye,
while the world is teeming with animal forms which he has not time in
his short day of life to stop to examine; another will study the land
forms and read the earth's history from the rocks and geological strata,
but here again nature's volume is so large that he has time to read but
a small fraction of the whole. Another studies the human body and learns
to read from its expressions the signs of health and sickness, and to
prescribe remedies for its ills; but in this field also he has found it
necessary to divide the work, and so we have specialists for almost
every organ of the body.
2. THE NATURE OF PERCEPTION
HOW A PERCEPT IS FORMED.--How, then, do we proceed to the discovery of
this world of objects? Let us watch the child and learn the secret from
him. Give the babe a ball, and he applies every sense to it to discover
its qualities. He stares at it, he takes it in his hands and turns it
over and around, he lifts it, he strokes it, he punches it and jabs it,
he puts it to his mouth and bites it, he drops it, he throws it and
creeps after it. He leaves no stone unturned to find out what that thing
really is. By means of the _qualities_ which come to him through the
avenues of sense, he constructs the _object_. And not only does he come
to know the ball as a material object, but he comes to know also its
uses. He is forming his own best definition of a ball in terms of the
sensations which he gets from it and the uses to which he puts it, and
all this even before he can name it or is able to recognize its name
when he hears it. How much better his method than the one he will have
to follow a little later when he goes to school and learns that "A ball
is a spherical body of any substance or size, used to play with, as by
throwing, kicking, or knocking, etc.!"
THE PERCEPT INVOLVES ALL RELATIONS OF THE OBJECT.--Nor is the case in
the least different with ourselves. When we wish to learn about a new
object or discover new facts about an old one, we do precisely as the
child does if we are wise. We apply to it every sense to which it will
afford a stimulus, and finally arrive at the object through its various
qualities. And just in so far as we have failed to use in connection
with it every sense to which it can minister, just in that degree will
we have an incomplete perception of it. Indeed, just so far as we have
failed finally to perceive it in terms of its functions or uses, in that
far also have we failed to know it completely. Tomatoes were for many
years grown as ornamental garden plants before it was discovered that
the tomatoes could minister to the taste as well as to the sight. The
clothing of civilized man gives the same sensation of texture and color
to the savage that it does to its owner, but he is so far from
perceiving it in the same way that he packs it away and continues to go
naked. The Orientals, who disdain the use of chairs and prefer to sit
cross-legged on the floor, can never perceive a chair just as we do who
use chairs daily, and to whom chairs are so saturated with social
suggestions and associations.
THE CONTENT OF THE PERCEPT.--The percept, then, always contains a basis
of _sensation_. The eye, the ear, the skin or some other sense organ
must turn in its supply of sensory material or there can be no percept.
But the percept contains more than just sensations. Consider, for
example, your percept of an automobile flashing past your windows. You
really _see_ but very little of it, yet you _perceive_ it as a very
familiar vehicle. All that your sense organs furnish is a more or less
blurred patch of black of certain size and contour, one or more objects
of somewhat different color whom you know to be passengers, and various
sounds of a whizzing, chugging or roaring nature. Your former experience
with automobiles enables you to associate with these meager sensory
details the upholstered seats, the whirling wheels, the swaying movement
and whatever else belongs to the full meaning of a motor car.
The percept that contained only sensory material, and lacked all memory
elements, ideas and meanings, would be no percept at all. And this is
the reason why a young child cannot see or hear like ourselves. It lacks
the associative material to give significance and meaning to the sensory
elements supplied by the end-organs. The dependence of the percept on
material from past experience is also illustrated in the common
statement that what one gets from an art exhibit or a concert depends on
what he brings to it. He who brings no knowledge, no memory, no images
from other pictures or music will secure but relatively barren percepts,
consisting of little besides the mere sensory elements. Truly, "to him
that hath shall be given" in the realm of perception.
THE ACCURACY OF PERCEPTS DEPENDS ON EXPERIENCE.--We must perceive
objects through our motor response to them as well as in terms of
sensations. The boy who has his knowledge of a tennis racket from
looking at one in a store window, or indeed from handling one and
looking it over in his room, can never know a tennis racket as does the
boy who plays with it on the court. Objects get their significance not
alone from their qualities, but even more from their use as related to
our own activities.
Like the child, we must get our knowledge of objects, if we are to get
it well, from the objects themselves at first hand, and not second hand
through descriptions of them by others. The fact that there is so much
of the material world about us that we can never hope to learn it all,
has made it necessary to put down in books many of the things which have
been discovered concerning nature. This necessity has, I fear, led many
away from nature itself to books--away from the living reality of things
to the dead embalming cases of words, in whose empty forms we see so
little of the significance which resides in the things themselves. We
are in danger of being satisfied with the _forms_ of knowledge without
its _substance_--with definitions contained in words instead of in
qualities and uses.
NOT DEFINITIONS, BUT FIRST-HAND CONTACT.--In like manner we come to know
distance, form and size. If we have never become acquainted with a mile
by actually walking a mile, running a mile, riding a bicycle a mile,
driving a horse a mile, or traveling a mile on a train, we might listen
for a long time to someone tell how far a mile is, or state the distance
from Chicago to Denver, without knowing much about it in any way except
word definitions. In order to understand a mile, we must come to know it
in as many ways as possible through sense activities of our own.
Although many children have learned that it is 25,000 miles around the
earth, probably no one who has not encircled the globe has any
reasonably accurate notion just how far this is. For words cannot take
the place of perceptions in giving us knowledge. In the case of shorter
distances, the same rule holds. The eye must be assisted by experience
of the muscles and tendons and joints in actually covering distance, and
learn to associate these sensations with those of the eye before the
eye alone can be able to say, "That tree is ten rods distant." Form and
size are to be learned in the same way. The hands must actually touch
and handle the object, experiencing its hardness or smoothness, the way
this curve and that angle feels, the amount of muscular energy it takes
to pass the hand over this surface and along that line, the eye taking
note all the while, before the eye can tell at a glance that yonder
object is a sphere and that this surface is two feet on the edge.
3. THE PERCEPTION OF SPACE
Many have been the philosophical controversies over the nature of space
and our perception of it. The psychologists have even quarreled
concerning whether we possess an _innate_ sense of space, or whether it
is a product of experience and training. Fortunately, for our present
purpose we shall not need to concern ourselves with either of these
controversies. For our discussion we may accept space for what common
sense understands it to be. As to our sense of space, whatever of this
we may possess at birth, it certainly has to be developed by use and
experience to become of practical value. In the perception of space we
must come to perceive _distance_, _direction_, _size_, and _form_. As a
matter of fact, however, size is but so much distance, and form is but
so much distance in this, that, or the other direction.
THE PERCEIVING OF DISTANCE.--Unquestionably the eye comes to be our
chief dependence in determining distance. Yet the muscle and joint
senses give us our earliest knowledge of distance. The babe reaches for
the moon simply because the eye does not tell it that the moon is out of
reach. Only as the child reaches for its playthings, creeps or walks
after them, and in a thousand ways uses its muscles and joints in
measuring distance, does the perception of distance become dependable.
At the same time the eye is slowly developing its power of judging
distance. But not for several years does visual perception of distance
become in any degree accurate. The eye's perception of distance depends
in part on the sensations arising from the muscles controlling the eye,
probably in part from the adjustment of the lens, and in part from the
retinal image. If one tries to look at the tip of his nose he easily
feels the muscle strain caused by the required angle of adjustment. We
come unconsciously to associate distance with the muscle sensations
arising from the different angles of vision. The part played by the
retinal image in judging distance is easily understood in looking at two
trees, one thirty feet and the other three hundred feet distant. We note
that the nearer tree shows the _detail_ of the bark and leaves, while
the more distant one lacks this detail. The nearer tree also reflects
more _light_ and _color_ than the one farther away. These minute
differences, registered as they are on the retinal image, come to stand
for so much of distance.
The ear also learns to perceive distance through differences in the
quality and the intensity of sound. Auditory perception of distance is,
however, never very accurate.
THE PERCEIVING OF DIRECTION.--The motor senses probably give us our
first perception of direction, as they do of distance. The child has to
reach this way or that way for his rattle; turn the eyes or head so far
in order to see an interesting object; twist the body, crawl or walk to
one side or the other to secure his bottle. In these experiences he is
gaining his first knowledge of direction.
Along with these muscle-joint experiences, the eye is also being
trained. The position of the image on the retina comes to stand for
direction, and the eye finally develops so remarkable a power of
perceiving direction that a picture hung a half inch out of plumb is a
source of annoyance. The ear develops some skill in the perception of
direction, but is less dependable than the eye.
4. THE PERCEPTION OF TIME
The philosophers and psychologists agree little better about our sense
of time than they do about our sense of space. Of this much, however, we
may be certain, our perception of time is subject to development and
training.
NATURE OF THE TIME SENSE.--How we perceive time is not so well
understood as our perception of space. It is evident, however, that our
idea of time is simpler than our idea of space--it has less of content,
less that we can describe. Probably the most fundamental part of our
idea of time is _progression_, or change, without which it is difficult
to think of time at all. The question then becomes, how do we perceive
change, or succession?
If one looks in upon his thought stream he finds that the movement of
consciousness is not uniformly continuous, but that his thought moves in
pulses, or short rushes, so to speak. When we are seeking for some fact
or conclusion, there is a moment of expectancy, or poising, and then the
leap forward to the desired point, or conclusion, from which an
immediate start is taken for the next objective point of our thinking.
It is probable that our sense of the few seconds of passing time that
we call the _immediate present_ consists of the recognition of the
succession of these pulsations of consciousness, together with certain
organic rhythms, such as heart beat and breathing.
NO PERCEPTION OF EMPTY TIME.--Our perception does not therefore act upon
empty time. Time must be filled with a procession of events, whether
these be within our own consciousness or in the objective world without.
All longer periods of time, such as hours, days, or years, are measured
by the events which they contain. Time filled with happenings that
interest and attract us seems short while passing, but longer when
looked back upon. On the other hand, time relatively empty of
interesting experience hangs heavy on our hands in passing, but, viewed
in retrospect, seems short. A fortnight of travel passes more quickly
than a fortnight of illness, but yields many more events for the memory
to review as the "filling" for time.
Probably no one has any very accurate feeling of the length, that is,
the actual _duration_ of a year--or even of a month! We therefore divide
time into convenient units, as weeks, months, years and centuries. This
allows us to think of time in mathematical terms where immediate
perception fails in its grasp.
5. THE TRAINING OF PERCEPTION
In the physical world as in the spiritual there are many people who,
"having eyes, see not and ears, hear not." For the ability to perceive
accurately and richly in the world of physical objects depends not alone
on good sense organs, but also on _interest_ and the habit of
_observation_. It is easy if we are indifferent or untrained to look at
a beautiful landscape, a picture or a cathedral without _seeing_ it; it
is easy if we lack interest or skill to listen to an orchestra or the
myriad sounds of nature without _hearing_ them.
PERCEPTION NEEDS TO BE TRAINED.--Training in perception does not depend
entirely on the work of the school. For the world about us exerts a
constant appeal to our senses. A thousand sights, sounds, contacts,
tastes, smells or other sensations, hourly throng in upon us, and the
appeal is irresistible. We must in some degree attend. We must observe.
Yet it cannot be denied that most of us are relatively unskilled in
perception; we do not know how, or take the trouble to observe. For
example, a stranger was brought into the classroom and introduced by the
instructor to a class of fifty college students in psychology. The class
thought the stranger was to address them, and looked at him with mild
curiosity. But, after standing before them for a few moments, he
suddenly withdrew, as had been arranged by the instructor. The class
were then asked to write such a description of the stranger as would
enable a person who had never seen him to identify him. But so poor had
been the observation of the class that they ascribed to him clothes of
four different colors, eyes and hair each of three different colors, a
tie of many different hues, height ranging from five feet and four
inches to over six feet, age from twenty-eight to forty-five years, and
many other details as wide of the mark. Nor is it probable that this
particular class was below the average in the power of perception.
SCHOOL TRAINING IN PERCEPTION.--The school can do much in training the
perception. But to accomplish this, the child must constantly be brought
into immediate contact with the physical world about him and taught to
observe. Books must not be substituted for things. Definitions must not
take the place of experiment or discovery. Geography and nature study
should be taught largely out of doors, and the lessons assigned should
take the child into the open for observation and investigation. All
things that live and grow, the sky and clouds, the sunset colors, the
brown of upturned soil, the smell of the clover field, or the new mown
hay, the sounds of a summer night, the distinguishing marks by which to
identify each family of common birds or breed of cattle--these and a
thousand other things that appeal to us from the simplest environment
afford a rich opportunity for training the perception. And he who has
learned to observe, and who is alert to the appeal of nature, has no
small part of his education already assured.
6. PROBLEMS IN OBSERVATION AND INTROSPECTION
1. Test your power of observation by walking rapidly past a well-filled
store window and then seeing how many of the objects you can name.
2. Suppose a tailor, a bootblack, a physician, and a detective are
standing on the street corner as you pass by. What will each one be most
likely to observe about you? _Why?_
3. Observe carefully green trees at a distance of a few rods; a quarter
of a mile; a mile; several miles. Describe differences (1) in color, (2)
in brightness, or light, and (3) in detail.
4. How many common birds can you identify? How many kinds of trees? Of
wild flowers? Of weeds?
5. Observe the work of an elementary school for the purpose of
determining:
a. Whether the instruction in geography, nature study, agriculture,
etc., calls for the use of the eyes, ears and fingers.
b. Whether definitions are used in place of first-hand information in
any subjects.
c. Whether the assignment of lessons to pupils includes work that would
require the use of the senses, especially out of doors.
d. Whether the work offered in arithmetic demands the use of the senses
as well as the reason.
e. Whether the language lessons make use of the power of observation.