Revived experience is memory. Since it is memory that enables us to live our lives over again, brings the past up to the present, it is one of the most wonderful aspects of our natures. The importance of memory is at once apparent if we try to imagine what life would be without it. If our life were only perceptual, if it were only the sights and sounds and smells and tastes of the pa.s.sing moment, it would have little meaning, it would be bare and empty. But instead of our perceptions being our whole life, they are only the starting points of life. Perceptions serve to arouse groups of memory images or ideas, and the groups of ideas enrich the pa.s.sing moment and give meaning to the pa.s.sing perceptions, which otherwise would have no meaning.

Suppose I am walking along the street and meet a friend. I see him, speak to him, and pa.s.s on. But after I have pa.s.sed on, I have ideas. I think of seeing my friend the day before. I think of what he said and of what he was doing, of what I said and of what I was doing. Perhaps for many minutes there come ideas from my past experience. These ideas were aroused by the perception of my friend. The perception was momentary, but it started a long train of memory ideas.

I pa.s.s on down the street and go by a music store. Within the store, a victrola is playing _Jesus, Lover of My Soul_. The song starts another train of memory ideas. I think of the past, of my boyhood days and Sunday school, my early home and many scenes of my childhood. For several minutes I am so engrossed with the memory images that I scarcely notice anything along the street. Again, the momentary perception, this time of sounds, served to revive a great number of ideas, or memories, of the past.

These ill.u.s.trations are typical of our life. Every moment we have perceptions. These perceptions arouse ideas of our past life and experience. One of these ideas evokes another, and so an endless chain of images pa.s.ses along. The older we become, the richer is our ideational life. While we are children, the perceptions const.i.tute the larger part of our mental life, but as we become older, larger and larger becomes the part played by our memory images or ideas. A child is not content to sit down and reflect, giving himself up to the flow of ideas that come up from his past experience, but a mature person can spend hours in recalling past experience. This means that the older we grow, the more we live in the past, the less we are bound down by the present, and when we are old, instead of perceptions being the main part of mental life, they but give the initial push to our thoughts which go on in an endless chain as long as we live.

=The Physiological Basis of Memory.= It will be remembered that the basis of perception is the agitation of the brain caused by the stimulation of a sense organ by an external thing or force. If there is no stimulation of a sense organ, there is no sensation, no perception. Now, just as the basis of sensation and perception is brain activity, so it is also the basis of ideas. In sensation, the brain activity is set up from without.

In memory, when we have ideas, the brain activity is set up from within and is a fainter revival of the activity originally caused by the stimulation of the sense organ. Our ideas are just as truly conditioned or caused by brain activity as are our sensations.

Memory presents many problems, and psychologists have been trying for many years to solve them. We shall now see what they have discovered and what is the practical significance of the facts.

=Relation of Memory to Age and s.e.x.= It is a common notion that memory is best when we are young, but such is not the case. Numerous experiments have shown that all aspects of memory improve with age. Some aspects of memory improve more than others, and they improve at different times and rates; but all aspects do improve. From the beginning of school age to about fourteen years of age the improvement of most aspects of memory is rapid.

If we p.r.o.nounce a number of digits to a child of six, it can reproduce but few of them, a child of eight or ten can reproduce more, a child of twelve can reproduce still more, and an adult still more. If we read a sentence to children of different ages, we find that the older children can reproduce a longer sentence. If we read a short story to children of different ages, and then require them to reproduce the story in their own words, the older children reproduce more of the story than do the young children.[5]

[5] See age and s.e.x graphs, pp. 184, 188, 189.

Girls excel boys in practically all the aspects of memory.

In rote memory, that is, memory for lists of unrelated words, there is not much difference; but the girls are somewhat better. However, in the ability to remember the ideas of a story, girls excel boys at every age.

This superiority of girls over boys is not merely a matter of memory. A girl is superior to a boy of the same age in nearly every way. This is merely a fact of development. A girl develops faster than a boy, she reaches maturity more quickly, in mind as well as in body. Although a girl is lighter than a boy at birth, on the average she gains in weight faster and is heavier at twelve than a boy of the same age. She also gains faster in height, and for a few years in early adolescence is taller than a boy of the same age. Of course, boys catch up and finally become much taller and heavier than girls. Similarly, a girl's mind develops faster than the mind of a boy, as shown in memory and other mental functions.

=The Improvement of Memory by Practice.= All aspects of memory can be improved by practice, some aspects much, other aspects little. The memory span for digits, or letters, or words, or for objects cannot be much improved, but memory for ideas that are related, as the ideas of a story, can be considerably improved. In extensive experiments conducted in the author's laboratory, it was found that a person who at first required an hour to memorize the ideas in a certain amount of material, could, after a few months' practice, memorize the same amount in fifteen minutes. And in the latter case the ideas would be better remembered than they were at the beginning of the experiment. Not only could a given number of ideas be learned in less time, but they would be better retained when learned in the shorter time. If a person comes to us for advice as to how to improve his memory, what should we tell him? In order to answer the question, we must consider the factors of a good memory.

=Factors of a Good Memory.= (1) The first requirement is to get a good impression in the beginning. Memory is revived experience. The more vivid and intense the first experience, the more sure will be the later recall. So if we wish to remember an experience, we must experience it in the first place under the most favorable conditions. The thing must be seen clearly, it must be understood, it must be in the focus of consciousness.

The best teaching is that which leads the child to get the clearest apprehension of what is taught. If we are teaching about some concrete thing, a plant, a machine, we should be sure that the child sees the essential points, should be sure that the main principles enter his consciousness. We should find out by questioning whether he really does clearly understand what we are trying to get him to understand. Often we think a pupil or student has forgotten, when the fact is that he never really knew the thing which we wished to have him remember.

The first requisite to memory, then, is to _know in the first place_. If we wish to remember knowledge, the knowledge must be seen in the clearest light, really _be_ knowledge, at the outset. Few people ever really learn how to learn. They never see anything clearly, they never stick to a point till it is apprehended in all its relations and bearings; consequently they forget, largely because they never really knew in the fullest sense.

Most teaching is too abstract. The teacher uses words that have no meaning to the pupil. Too much teaching deals with things indirectly. We study _about_ things instead of studying things. In geography, for example, we study about the earth, getting our information from a book.

We read about land formations, river courses, erosion, etc., when instead we should study these objects and processes themselves. The first thing in memory, then, is clear apprehension, clear understanding, vivid and intense impression.

(2) The second thing necessary to memory is to repeat the experience.

First we must get a clear impression, then we must repeat the experience if we would retain it. It is a mistake to believe that if we have once understood a thing, we will always thereafter remember it. We must think our experiences over again if we wish to fix them for permanent retention.

We must organize our experience. To organize experience means to think it over in its helpful relations. In memory, one idea arouses another.

When we have one idea, what other idea will this arouse? It depends on what connections this idea has had in our minds in the past. It depends on the a.s.sociations that it has, and a.s.sociations depend on our thinking the ideas over together.

Teachers and parents should help children to think over their experiences in helpful, practical relations. Then in the future, when an idea comes to mind, it brings along with it other ideas that have these helpful, practical relations. We must not, then, merely repeat our experiences, but must repeat them in helpful connections or a.s.sociations. In organizing our experience, we must systematize and cla.s.sify our knowledge.

One of the chief differences in men is in the way they organize their knowledge. Most of us have experiences abundant enough, but we differ in the way we work over and organize these experiences. Organization not only enables us to remember our experience, but brings our experience back in the right connections.

The advice that should be given to a student is the following: Make sure that you understand. If the matter is a lesson in a book, go through it trying to get the main facts; then go through it again, trying to see the relation of all the facts. Then try to see the facts in relation to your wider experience. If it is a history lesson, think of the facts of the lesson in their relation to previous chapters. Think of the details in their bearing on wider and larger movements.

A teacher should always hold in mind the facts in regard to memory, and should make her teaching conform to them. She should carefully plan the presentation of a new topic so as to insure a clear initial impression.

A new topic should be presented orally by the teacher, with abundant ill.u.s.tration and explanation. It cannot be made too concrete, it cannot be made too plain and simple.

Then after the teacher has introduced and made plain the new topic, the pupil reads and studies further. At the next recitation of the cla.s.s, the first thing in order should be a discussion, on the part of the pupils. This will help the pupils to get the facts cleared up and will help the teacher to find out whether the pupils have the facts right.

The first part of the recitation should also be a time for questions.

Everything should now be made clear, if there are any errors or misunderstandings on the pupil's part. Of course any procedure in a recitation should depend upon the nature of the material and to some extent on the stage of advancement of the pupil; but in general such a procedure as that just outlined will be most satisfactory and economical: first clear initial presentation by the teacher; then reading and study on the part of the pupil, and third, discussions on the following day.

Teachers should also endeavor to show students how to study to the best advantage. Pupils do not know how to study. They do not know what to look for, and do not know how to find it after they know what they are looking for. They should be shown. Of course, some of them learn without help how to study. But some never learn, and it would be a great saving of time to help all of them master the arts of study and memorizing.

A very important factor in connection with memory is the matter of meaning. If a person will try to memorize a list of nonsense words, he will find that it is much more difficult than to memorize words that have meaning. This is a significant fact. It means that as material approaches nonsense, it is difficult to memorize. Therefore we should always try to grasp the meaning of a thing, its significance. In science, let us always ask, what is the meaning of this fact? What bearing does it have on other facts? How does it affect the meaning of other facts?

=Kinds of Memories.= We should not speak of memory as if it were some sort of power like muscular strength. We should always speak of _memories_.

Memories may be cla.s.sified from several different points of view: A cla.s.sification may be based on the kind of material, as memory for concrete things, the actual objects of experience, on the one hand, and memory for abstract material, such as names of things, their attributes and relations, on the other. Again, we can base a cla.s.sification on the type of ideation to which the material appeals, as auditory memory, visual memory, motor memory. We can also base a cla.s.sification on the principle of _meaning_. This principle of cla.s.sification would give us at least three cla.s.ses: memory for ideas as expressed in sentences, logical memory; memory for series of meaningful words not logically related in sentences, rote memory; memory for series of meaningless words, a form of rote memory. This cla.s.sification is not meant to be complete, but only suggestive. With every change in the kind of material, the method of presenting the material to the subject, or the manner in which the subject deals with the material, there may be a change in the effectiveness of memory.

While these different kinds or aspects of memory may have some relation to one another, they are to some extent independent. One may have a good rote memory and a poor logical memory, or a poor rote memory and a good logical memory. That is to say, one may be very poor at remembering the exact words of a book, but be good at remembering the meaning, the ideas, of the book. One may be good at organizing meaningful material but poor at remembering mere words. On the other hand, these conditions may be reversed; one may remember the words but never get the meaning.

It is of course possible that much of this difference is due to habit and experience, but some of the difference is beyond doubt due to original differences in the nervous system and brain. These differences should be determined in the case of all children. It is quite a common thing to find a feeble-minded person with a good rote memory, but such a person never has a good logical memory. One can have a good rote memory without understanding, one cannot have a good logical memory without understanding.

Let us now ask the question, why can one remember better words that are connected by logical relations than words that have no such connection?

If we read to a person a list of twenty nonsense words, the person can remember only two or three; but if a list of twenty words connected in a sentence were read to a person, in most cases, all of them would be reproduced. The reason is that the words in the latter case are not new.

We already know the words. They are already a part of our experience. We have had days, perhaps years, of experience with them. All that is now new about them is perhaps a slightly new relation.

Moreover, the twenty words may contain but one, or at most only a few, ideas, and in this case it is the ideas that we remember. The ideas hold the words together. If the twenty words contain a great number of ideas, then we cannot remember all of them from one reading. If I say, "I have a little boy who loves his father and mother very much, and this boy wishes to go to the river to catch some fish," one can easily remember all these words after one reading. But if I say, "The stomach in all the Salmonidae is syphonal and at the pylorus are fifteen to two hundred comparatively large pyloric coeca"; although this sentence is shorter, one finds it more difficult to remember, and the main reason is that the words are not so familiar.

=Memory and Thinking.= What is the relation of memory to thinking and the other mental functions? One often hears a teacher say that she does not wish her pupils to depend on memory, but wishes them to reason things out. Such a statement shows a misunderstanding of the facts; for reasoning itself is only the recall of ideas in accordance with the laws of a.s.sociation. Without memory, there would be no reasoning, for the very material of thought is found to be the revived experiences which we call ideas, memories.

One of the first requisites of good thinking is a reliable memory. One must have facts to reason, and these facts must come to one in memory to be available for thought. If one wishes to become a great thinker in a certain field, he must gain experience in that field and organize that experience in such a way as to remember it and to recall it when it is wanted.

What one does deplore is memory for the mere words with no understanding of the meaning. In geometry, for example, a student sometimes commits to memory the words of a demonstration, with no understanding of the meaning. Of course, that is worse than useless. One should remember the meaning of the demonstration. If one has memorized the words only, he cannot solve an original problem in geometry. But if he has understood the meaning of the demonstration, then he recalls it, and is enabled to solve the problem. If one does not remember the various facts about the relationships in a triangle, he cannot solve a problem of the triangle until he has worked out and discovered the necessary facts. Then memory would make them available for the solution of the problem.

=Memory and School Standing.= That memory plays a large part in our life is evident; and, of course, it is an important factor in all school work. It matters not what we learn, if we do not remember it. The author has made extensive experiments to determine the relation that memory has to a child's progress in school.

The method used was to give logical memory tests to all the children in a school and then rank the children in accordance with their abilities to reproduce the story used in the test. Then they were ranked according to their standing in their studies. A very high correlation was found.

On the whole, the pupils standing highest in the memory tests were found to stand highest in their studies. It is true, of course, that they did not stand highest merely because they had good memories, but because they were not only better in memory, but were better in most other respects too. Pupils that are good in logical memory are usually good in other mental functions.

A test of logical memory is one of the best to give us an idea of the school standing of pupils. Not only is the retention of ideas of very great importance itself, but the acquiring of ideas, and the organizing of them in such a way as to remember them involves nearly all the mental functions. The one who remembers well ideas logically related, is the one who pays the closest attention, the one who sees the significance, the one who organizes, the one who repeats, the one who turns things over in his mind. A logical memory test is therefore, to some extent, a test of attention, a.s.sociation, power of organization as well as of memory; in a word, it is a test of mental power.

Other things being equal, a person whose power of retention is good has a great advantage over his fellows who have poor ability to remember.

Suppose we consider the learning of language. The pupil who can look up the meaning of a word just once and remember it has an advantage over the person who has to look up the meaning of the word several times before it is retained. So in any branch of study, the person who can acquire the facts in less time than another person, has the extra time for learning something else or for going over the same material and organizing it better. The scientist who remembers all the significant facts that he reads, and sees their bearing on his problems, has a great advantage over the person who does not remember so well.

Of course, there are certain dangers in having a good memory, just as there is danger in being brilliant generally. The quick learner is in danger of forming slovenly habits. A person who learns quickly is likely to form the habit of waiting till the last minute to study his lesson and then getting a superficial idea of it. The slow learner must form good habits of study to get on at all.

Teachers and parents should prevent the bright children from forming bad habits of study. The person who learns quickly and retains well should be taught to be thorough and to use the advantage that comes from repet.i.tion. The quick learner should not be satisfied with one attack on his lesson, but should study the lesson more than once, for even the brilliant learner cannot afford to neglect the advantages that come from repet.i.tion. A person with poor memory and only mediocre ability generally can make up very much by hard work and by work that takes advantage of all the laws of economical learning. But he can never compete successfully with the person who works as hard as he does and who has good powers of learning and retention.

The author has found that in a large cla.s.s of a hundred or more, there is usually a person who has good memory along with good mental ability generally, and is also a hard worker. Such a person always does the best work in the cla.s.s. A person with poor memory and poor mental powers generally cannot hope to compete with a person of good memory, good mental powers generally, if that person is also a good worker.

=Learning and Remembering.= A popular fallacy is expressed in the saying "Easy come, easy go." The person who is the best learner is also the best in retaining what is learned, provided all other conditions are the same. This matter was determined in the following way: A logical memory test was given to all the children in a city school system. A story was read to the pupils and then reproduced by them in writing. The papers were corrected and graded and nothing more was said about the test for one month. Then at the same time in every room, the teachers said, "You remember the story I read to you some time ago and which I asked you to reproduce. Well, I wish to see how much of the story you still remember." The pupils were then required to write down all the story that they could recall.

It was found that, in general, the children who write the most when the story is first read to them, write the most after the lapse of a month, and the poorest ones at first are the poorest ones at the end of the month. Of course, the correspondence is not perfect, but in some cases, in some grades, it is almost so.

The significance of this experiment is very great. It means that the pupil who gets the most facts from a lesson will have the most facts at any later time. This is true, of course, only if other things are equal.

If one pupil studies about the matter more, reflects upon it, repeats it in his mind, of course this person will remember more, other things being equal. But if neither reviews the matter, or if both do it to an equal extent, then the one who learns the most in the first place, remembers the most at a later time.