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
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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.