The Science of Human Nature

a of this relation, almost universally held till recently, was that the mind or spirit lived in the body but was more or less independent of the body. The body has been looked upon as a hi

ic evidence one way or the other. The only mind that science knows anything about is bound up very closely with body. This is no

of severe bodily injury, of blindness or deafness. We have, perhaps, seen some one struck upon the head by a club, or run over by an automobile, and have noted the tremendous consequences to the person's mind. In su

First of all, we note the dependence of mind upon sense organs. We see only with our eyes. If we close the eyelids, we cannot see. If we are born blind

not hear. In like manner, we taste only by means of the taste organs in the mouth, and smell only with the organs of smell in the nose. In a word,

ed is the nervous system. The sense organs themselves are merely modifications of the nerve ends together with certain mechanisms for enabling stimuli to act on the nerve ends. The eye is merely the optic nerve spread out to form the retina and modified in certain ways to m

an image on each retina. The retina is sensitive to the light. The light produces chemical changes on the retina. These changes set up an excitation in the optic nerves, which is conduct

ut our primary, sensory experience. By primary, sensory experience is meant our immediate, direct knowledge of any aspect of the world. In this field of our conscious life, we are entirely dependent upon sens

eyes to convince himself that the mind sees by means of eyes, which are physical sense organs. One has but t

have before. This close dependence of mind upon body must give to the body a place in our scheme of education that it would not have under any other view of the mind. We wish to emphasize here that this statement of the close relation of the mind and body is not a theory which one may accept or not. It is a simple statement of fact. It is

he sensations are the elementary experiences out of which all mental life is built, it is necessary for us

ina corresponds to the sensitive plate of the camera. The light coming from objects toward which the eyes are directed is focused on the retina, forming there an image of the object. The light thus focused on the retina sets up

give us the colors yellow and red. The intermediate frequencies give us the intermediate colors blue-green and orange. By vibration frequencies is meant the rate at which t

bration than that producing red do not affect the eye, and faster than that producing violet do not affect the eye. The lightness and darkness of a color are dependent upon the int

the fact that certain vibration frequencies neutralize each other in their effect on the retina, so far as producing color is

vibration frequency give the different colors. Changes in intensity give the different brightnesses: black, gray, and wh

ade, already mentioned, some further intere

. Orange induces greenish blue, and greenish blue induces orange. Violet induces yellowish green, and yellowish green induces violet. These color-pairs are known as antagonistic or complementary colors. Each one of a pair enhances the effec

They must be taken account of in all arrangements of colors and tints, fo

n, they neutralize each other and produce only gray. All the pairs of complementary colors mentioned above act in the same way, producing, if mixed in the right proportion, no color, but gray. If colored disks not complementary are mixed by rotation on a motor, they produce an intermediate color. Red and yellow give orange. Blue and green give bluish green. Ye

f he will then gaze steadily at the colored paper for a half-minute, it will be found that if the colored paper is removed one sees its complementary color. If the head is not moved, this complementary color has the same size and shape as the original colored piece of

ng at a certain color for some time, a half-minute or more, then looks at som

s if they were illuminated with white light, losing the yellow aspect. But if one then goes out into white light, everything looks bluish. The negative after-image of the yellow being cast upon everything makes the surroundings look blue, for the after-image of ye

The reader should familiarize himself with the physiology of the ear by reference to physiologies. The drum-skin, the three little bones of the middle ear, and th

of the air vibrations. The low bass notes are produced by the low vibration frequencies. The high notes are produced by the high vibration frequenc

. In each case the sense organ is some special adaptation of the nerve-endings with appropriate ap

s sensitive to sweet, sour, salt, and bitter. In the nose we have an organ that is sensitive t

and definite sensations produced by different kinds of organs. The sense of warmth is produced by different organs from those which produce

ations which are the basis of our perception of motion, and of the position of the body and its members. In the semicircular canals

erve-endings are specially adapted to receive each its particular form of stimulation. This stimulation of our sense organs is the basis or cause of our sensations. And our sensations are the elementary stuff of

all therefore discuss defects of these two organs only. Since sensations are the primary stuff out of which mind is made, and since sight and hearing are the most important

, large or small. To take plastic material and make lenses and shutters and curtains is a great task. The curvature of the front of the eye and of the front and back of the crystalline lens is never qui

about it. In some cases, the eye focuses the light before it reaches the retina. Such cases are known as nearsightedness and are corrected by having placed in front of the eyes concave lenses of the proper strength. These lenses diverge the rays

wings. Consult a good text in physiology. Noyes' University of Missou

one direction is different from that in others. For example, the vertical curvature may be more convex than the horizontal. Such a condition produces a serio

tically becomes thicker, more convex. This adjustment brings the rays to a focus on the retina, which is required for good vision. As we get old, the crystalline lens loses its power to change i

d and green. While only a small percentage of the population has this defect, it is nevertheless very important that those having it be detected. People having the defect should not be allowed to enter occupations in which the seeing of red and green is important. It was recently brought to the author's at

ildren showing any symptoms of eyestrain should be required to have their visual defects corrected by a competent oculist, and should be warned not to have the correction m

rough the Eustachian tube. The careful and frequent medical examination of school children cannot, therefore, be too strongly emphasized. The deafness or

n, nerves, and sense organs. The sense organs are special adaptations of the nerve-ends fo

cts of the sense organs are serious handicaps and should be corrected if possible. Visual defects are usually due to a misshapen eyeball and ca

EXER

dy. Enumerate the different lines of evidence whic

ending to show that the min

colors, and note the result. A simple device can be made for mixing colors, as follows: On a board stand a pane of glass. On one side of the glass put a colored paper and on the other side of the glass put a different color. By looking throug

nd gaze at the colored paper for about a half-minute, then blow the paper away and continue to gaze at the white background. Note the color that appears. Use different colors and tab

tion of the retina. With the eyes covered with several folds of thick black cloth go to a window, uncover the eyes and take a momentary look at the landscape, immediately co

nge comes over objects after the glasses have been worn for fifteen or twenty minutes? Describe your experience after removing the glasses. Plan and perform other

t on white and various shades of gray and bl

s long and one inch wide. Over one window put colored glass or any other colored material through which some light will pass. By holding up a pencil

hich women dress. What do yo

can obtain the Holmgren worsted

ce of cardboard. Above each row of letters on the chart is a number which indicates the distance at which it can be read by a normal eye. If the subject can read only the thirty-foot line, his vision is said to be 20/30; if only the forty-foot

very simply performed by rotating a wheel having spokes. Hold a light stick against the spokes so that it strikes each spoke. If the wheel is rotated so as to gi

s of the class can hear a watch-tick. The teacher can plan an experiment using whis

ld spots" on the skin. Warm the nail to about 40 d

back of the hand, you can s

e point of a needle, you can

or. Therefore in experiments with taste, the nostrils should be stopped up with cotton. It will be found, for example, that quinine and coffee are indistinguishable if their odors be elimi

S FOR CLA

Human Behavior, C

General and Applied, Chap

s of Psychology, Cha

of Educational Psyc

Psychology, Chapter I,