The Science of Human Nature: A Psychology for Beginners — Inside the Classic

PTER I. INTRODUCTION 1

CHAPTER II. DEVELOPMENT OF THE RACE AND OF THE INDIVIDUAL 18

CHAPTER III. MIND AND BODY 34

CHAPTER IV. INHERITED TENDENCIES 50

CHAPTER V. FEELING AND ATTENTION 73

CHAPTER VII. MEMORY 124

CHAPTER VIII. THINKING 152

CHAPTER IX. INDIVIDUAL DIFFERENCES 176

CHAPTER X. APPLIED PSYCHOLOGY 210

THE SCIENCE OF HUMAN NATURE

=Science.= Before attempting to define psychology, it will be helpful to make some inquiry into the nature of science in general. Science is knowledge; it is what we know. But mere knowledge is not science. For a bit of knowledge to become a part of science, its relation to other bits of knowledge must be found. In botany, for example, bits of knowledge about plants do not make a science of botany. To have a science of botany, we must not only know about leaves, roots, flowers, seeds, etc., but we must know the relations of these parts and of all the parts of a plant to one another. In other words, in science, we must not only _know_, we must not only have _knowledge_, but we must know the significance of the knowledge, must know its _meaning_. This is only another way of saying that we must have knowledge and know its relation to other knowledge.

A scientist is one who has learned to organize his knowledge. The main difference between a scientist and one who is not a scientist is that the scientist sees the significance of facts, while the non-scientific man sees facts as more or less unrelated things. As one comes to hunt for causes and inquire into the significance of things, one becomes a scientist. A thing or an event always points beyond itself to something else. This something else is what goes before it or comes after it,--is its cause or its effect. This causal relationship that exists between events enables a scientist to prophesy. By carefully determining what always precedes a certain event, a certain type of happening, a scientist is able to predict the event. All that is necessary to be able to predict an event is to have a clear knowledge of its true causes. Whenever, beyond any doubt, these causes are found to be present, the scientist knows the event will follow. Of course, all that he really _knows_ is that such results have always followed similar causes in the past. But he has come to have faith in the uniformity and regularity of nature. The chemist does not find sulphur, or oxygen, or any other element acting one way one day under a certain set of conditions, and acting another way the next day under exactly the same conditions. Nor does the physicist find the laws of mechanics holding good one day and not the next.

The scientist, therefore, in his thinking brings order out of chaos in the world. If we do not know the causes and relations of things and events, the world seems a very mixed-up, chaotic place, where anything and everything is happening. But as we come to know causes and relations, the world turns out to be a very orderly and systematic place. It is a lawful world; it is not a world of chance. Everything is related to everything else.

Now, the non-scientific mind sees things as more or less unrelated. The far-reaching causal relations are only imperfectly seen by it, while the scientific mind not only sees things, but inquires into their causes and effects or consequences. The non-scientific man, walking over the top of a mountain and noticing a stone there, is likely to see in it only a stone and think nothing of how it came to be there; but the scientific man sees quite an interesting bit of history in the stone. He reads in the stone that millions of years ago the place where the rock now lies was under the sea. Many marine animals left their remains in the mud underneath the sea. The mud was afterward converted into rock. Later, the shrinking and warping earth-crust lifted the rock far above the level of the sea, and it may now be found at the top of the mountain. The one bit of rock tells its story to one who inquires into its causes. The scientific man, then, sees more significance, more meaning, in things and events than does the non-scientific man.

Each science has its own particular field. Zoölogy undertakes to answer every reasonable question about animals; botany, about plants; physics, about motion and forces; chemistry, about the composition of matter; astronomy, about the heavenly bodies, etc. The world has many aspects. Each science undertakes to describe and explain some particular aspect. To understand all the aspects of the world, we must study all the sciences.

=A Scientific Law.= By _law_ a scientist has reference to uniformities which he notices in things and events. He does not mean that necessities are imposed upon things as civil law is imposed upon man. He means only that in certain well-defined situations certain events always take place, according to all previous observations. The Law of Falling Bodies may be cited as an example. By this law, the physicist means that in observing falling bodies in the past, he has noticed that they fall about sixteen feet in the first second and acquire in this time a velocity of thirty-two feet. He has noted that, taking into account the specific gravity of the object and the resistance of the air, this way of falling holds true of all objects at about the level of the sea.

The more we carefully study the events of the world, the more strongly we come to feel that definite causes, under the same circumstances, always produce precisely the same result. The scientist has faith that events will continue to happen during all the future in the same order of cause and effect in which they have been happening during all the past.

The astronomer, knowing the relations of the members of the solar system--the sun and planets--can successfully predict the occurrence of lunar and solar eclipses. In other fields, too, the scientist can predict with as much certainty as does the astronomer, provided his knowledge of the factors concerned is as complete as is the knowledge which the astronomer has of the solar system. Even in the case of human beings, uncertain as their actions seem to be, we can predict their actions when our knowledge of the factors is sufficiently complete. In a great many instances we do make such predictions. For example, if we call a person by name, we expect him to turn, or make some other movement in response. Our usual inability to make such predictions in the case of human beings is not because human beings are not subject to the law of cause and effect, it is not that their acts are due to chance, but that the factors involved are usually many, and it is difficult for us to find out all of them.

=The Science of Psychology.= Now, let us ask, what is the science of psychology? What kind of problems does it try to solve? What aspect of the world has it taken for its field of investigation?

We have said that each science undertakes to describe some particular aspect of the world. Human psychology is the science of human nature. But human nature has many aspects. To some extent, our bodies are the subject matter for physiology, anatomy, zoölogy, physics, and chemistry. Our bodies may be studied in the same way that a rock or a table might be studied. But a human being presents certain problems that a rock or table does not present. If we consider the differences between a human being and a table, we shall see at once the special field of psychology. If we stick a pin into a leg of the table, we get no response. If we stick a pin into a leg of a man, we get a characteristic response. The man moves, he cries out. This shows two very great differences between a man and a table. The man is _sensitive_ and has the power of action, the power of _moving himself_. The table is not sensitive, nor can it move itself. If the pin is thrust into one's own leg, one has _pain_. Human beings, then, are sensitive, conscious, acting beings. And the study of sensitivity, action, and consciousness is the field of psychology. These three characteristics are not peculiar to man. Many, perhaps all, animals possess them. There is, therefore, an animal psychology as well as human psychology.

A study of the human body shows us that the body-surface and many parts within the body are filled with sensitive nerve-ends. These sensitive nerve-ends are the sense organs, and on them the substances and forces of the world are constantly acting. In the sense organs, the nerve-ends are so modified or changed as to be affected by some particular kind of force or substance. Vibrations of ether affect the eye. Vibrations of air affect the ear. Liquids and solutions affect the sense of taste. Certain substances affect the sense of smell. Certain organs in the skin are affected by low temperatures; others, by high temperatures; others, by mechanical pressure. Similarly, each sense organ in the body is affected by a definite kind of force or substance.

This affecting of a sense organ is known technically as _stimulation_, and that which affects the organ is known as the _stimulus_.

Two important consequences ordinarily follow the stimulation of a sense organ. One of these is movement. The purpose of stimulation is to bring about movement. To be alive is to respond to stimulation. When one ceases to respond to stimulation, he is dead. If we are to continue alive, we must constantly adjust ourselves to the forces of the world in which we live. Generally speaking, we may say that every nerve has one end in a sense organ and the other in a muscle. This arrangement of the nerves and muscles shows that man is essentially a sensitive-action machine. The problems connected with sensitivity and action and the relation of each to the other constitute a large part of the field of psychology.

We said just now, that a nerve begins in a sense organ and ends in a muscle. This statement represents the general scheme well enough, but leaves out an important detail. The nerve does not extend directly to a muscle, but ordinarily goes by way of the brain. The brain is merely a great group of nerve cells and fibers which have developed as a central organ where a stimulation may pass from almost any sense organ to almost any muscle.

But another importance attaches to the brain. When a sense organ is stimulated and this stimulation passes on to the brain and agitates a cell or group of cells there, _we are conscious_. Consciousness shifts and changes with every shift and change of the stimulation.

The brain has still another important characteristic. After it has been stimulated through sense organ and nerve, a similar brain activity can be revived later, and this revival is the basis of _memory_. When the brain is agitated through the medium of a sense organ, we have _sensation_; when this agitation is revived later, we have a _memory idea_. A study of consciousness, or mind, the conditions under which it arises, and all the other problems involved, give us the other part of the field of psychology.

We are not merely acting beings; we are _conscious_ acting beings. Psychology must study human nature from both points of view. We must study man not only from the outside; that is, objectively, in the same way that we study a stone or a tree or a frog, but we must study him from the inside or subjectively. It is of importance to know not only how a man _acts_, but also how he _thinks and feels_.

It must be clear now, that human action, human behavior, is the main field of psychology. For, even though our main interests in people were in their minds, we could learn of the minds only through the actions. But our interests in other human beings are not in their minds but in _what they do_. It is true that our interest in ourselves is in our minds, and we can know these minds directly; but we cannot know directly the mind of another person, we can only guess what it is from the person's actions.

=The Problems of Psychology.= Let us now see, in some detail, what the various problems of psychology are. If we are to understand human nature, we must know something of man's past; we must therefore treat of the origin and development of the human race. The relation of one generation to that preceding and to the one following makes necessary a study of heredity. We must find out how our thoughts, feelings, sensations, and ideas are dependent upon a physical body and its organs. A study of human actions shows that some actions are unlearned while others are learned or acquired. The unlearned acts are known as _instincts_ and the acquired acts are known as _habits_. Our psychology must, therefore, treat of instincts and habits.

How man gets experience, and retains and organizes this experience must be our problem in the chapters on sensations, ideas, memory, and thinking. Individual differences in human capacity make necessary a treatment of the different types and grades of intelligence, and the compilation of tests for determining these differences. We must also treat of the application of psychology to those fields where a knowledge of human nature is necessary.

=Applied Psychology.= At the beginning of a subject it is legitimate to inquire concerning the possibility of applying the principles studied to practical uses, and it is very proper to make this inquiry concerning psychology. Psychology, being the science of human nature, ought to be of use in all fields where one needs to know the causes of human action. And psychology is applicable in these fields to the extent that the psychologist is able to work out the laws and principles of human action.

In education, for example, we wish to influence children, and we must go to psychology to learn about the nature of children and to find out how we can influence them. Psychology is therefore the basis of the science of education.

Since different kinds of work demand, in some cases, different kinds of ability, the psychology of individual differences can be of service in selecting people for special kinds of work. That is to say, we must have sometime, if we do not now, a psychology of professions and vocations. Psychological investigations of the reliability of human evidence make the science of service in the court room. The study of the laws of attention and interest give us the psychology of advertising. The study of suggestion and abnormal states make psychology of use in medicine. It may be said, therefore, that psychology, once abstract and unrelated to any practical interests, will become the most useful of all sciences, as it works out its problems and finds the laws of human behavior.

At present, the greatest service of psychology is to education. So true is this that a department has grown up called "educational psychology," which constitutes at the present time the most important subdivision of psychology. While in this book we treat briefly of the various applications of psychology, we shall have in mind chiefly its application to education.

=The Science of Education.= Owing to the importance which psychology has in the science of education, it will be well for us to make some inquiry into the nature of education. If the growth, development, and learning of children are all controlled and determined by definite causal factors, then a systematic statement of all these factors would constitute the science of education. In order to see clearly whether there is such a science, or whether there can be, let us inquire more definitely as to the kind of problems a science of education would be expected to solve.

There are four main questions which the science of education must solve: (1) What is the aim of education? (2) What is the nature of education? (3) What is the nature of the child? (4) What are the most economical methods of changing the child from what it is into what it ought to be?

The first question is a sociological question, and it is not difficult to find the answer. We have but to inquire what the people wish their children to become. There is a pretty general agreement, at least in the same community, that children should be trained in a way that will make them socially efficient. Parents generally wish their children to become honest, truthful, sympathetic, and industrious. It should be the aim of education to accomplish this social ideal. It should be the aim of the home and the school to subject children to such influences as will enable them to make a living when grown and to do their proper share of work for the community and state, working always for better things, and having a sympathetic attitude toward neighbors. Education should also do what it can to make people able to enjoy the world and life to the fullest and highest extent. Some such aim of education as this is held by all our people.

The second question is also answered. Psychological analysis reveals the fact that education is a process of becoming adjusted to the world. It is the process of acquiring the habits, knowledge, and ideals suited to the life we are to live. The child in being educated learns what the world is and how to act in it--how to act in all the various situations of life.

The third question--concerning the nature of the child--cannot be so briefly answered. In fact, it cannot be fully answered at the present time. We must know what the child's original nature is. This means that we must know the instincts and all the other inherited capacities and tendencies. We must know the laws of building up habits and of acquiring knowledge, the laws of retention and the laws of attention. These problems constitute the subject matter of educational psychology, and at present can be only partially solved. We have, however, a very respectable body of knowledge in this field, though it is by no means complete.

The answer to the fourth question is in part dependent upon the progress in answering the third. Economical methods of training children must be dependent upon the nature of children. But in actual practice, we are trying to find out the best procedure of doing each single thing in school work; we are trying to find out by experimentation. The proper way to teach children to read, to spell, to write, etc., must be determined in each case by independent investigation, until our knowledge of the child becomes sufficient for us to infer from general laws of procedure what the procedure in a particular case should be. We venture to infer what ought to be done in some cases, but generally we feel insecure till we have proved our inference correct by trying out different methods and measuring the results.

Education will not be fully scientific till we have definite knowledge to guide us at every step. What should we teach? When should we teach it? How should we teach it? How poorly we answer these questions at the present time! How inefficient and uneconomical our schools, because we cannot fully answer them! But they are answerable. We can answer them in part now, and we know how to find out the answer in full. It is just a matter of patient and extensive investigation. We must say, then, that we have only the beginnings of a science of education. The problems which a science of education must solve are almost wholly psychological problems. They could not be solved till we had a science of psychology. Experimental psychology is but a half-century old; educational psychology, less than a quarter-century old. In the field of education, the science of psychology may expect to make its most important practical contribution. Let us, then, consider very briefly the problems of educational psychology.