We observe in passing that the important principles already discussed stand in close mutual relation and dependence. Interest aids concentration by bringing all kinds of knowledge into close touch with the feelings. Interest puts incentives into every kind of information so as to arouse the will, which, in turn, unifies and controls the mental actions. But concentration has a reflex influence upon interest, because unity and conscious mastery give added pleasure to knowledge. The culture epochs are expected to contribute powerfully to both concentration and interest; to the former by supplying a series of rallying-points for educative effort, to the latter by furnishing matter suited to interest children. Induction is a natural method of acquiring and unifying knowledge in an interesting way. Apperception, in turn, is a principle of mental action which puts life and interest into inductive and concentrating processes. Every hour of school labor illustrates the value of apperception and teachers should find in it a constant antidote to faulty methods.
Apperception may be roughly defined at first as the process of acquiring new ideas by the aid of old ideas already in the mind. It makes the acquisition of new knowledge easier and quicker. Not that there is any easy road to learning, but there is a natural process which greatly accelerates the progress of acquisition, just as it is better to follow a highway over a rough country than to betake one's self to the stumps and brush. For example, if one is familiar with peaches, apricots will be quickly understood as a kindred kind of fruit, even though a little strange. A person who is familiar with electrical machinery will easily interpret the meaning and purpose of every part of a new electrical plant. One may perceive a new object without understanding it, but to apperceive it is to interpret its meaning by the aid of similar familiar notions.
If one examines a typewriter for the first time, it will take some pains and effort to understand its construction and use; but after examining a Remington, another kind will be more easily understood, because the principle of the first interprets that of the second. Suppose the Steppes of Russia are mentioned for the first time to a class. The word has little or no meaning or perhaps suggests erroneously a succession of stairs. But we remark that the steppes are like the prairies and plains to the west of the Mississippi river, covered with grass and fed on by herds. By awakening a familiar notion already in the mind and bringing it distinctly to the front, the new thing is easily understood. Again, a boy goes to town and sees a banana for the first time, and asks, "What is that? I never saw anything like that." He thinks he has no class of things to which it belongs, no place to put it. His father answers that it is to eat like an orange or a pear, and its significance is at once plain by the reference to something familiar.
Again, two men, the one a machinist and the other an observer unskilled in machines, visit the machinery hall of an exposition. The machinist observes a new invention and finds in it a new application of an old principle. As he passes along from one machine to another he is much interested in noting new devices and novel appliances and at the end of an hour he leaves the hall with a mind enriched. The other observer sees the same machines and their parts, but does not detect the principle of their construction. His previous knowledge of machines is not sufficient to give him the clue to their explanation. After an hour of uninterested observation he leaves the hall with a confused notion of shafts, wheels, cogs, bands, etc., but with no greater insight into the principles of machinery. Why has one man learned so much and the other nothing? Because the machinist's previous experience served as an interpreter and explained these new contrivances, while the other had no sufficient previous knowledge and so acquired nothing new. "To him that hath shall be given."
In the act of apperception the old ideas dwelling in the mind are not to be regarded as dead treasures stored away and only occasionally drawn out and used by a purposed effort of the memory, but they are living forces which have the active power of seizing and appropriating new ideas. Lazarus says they stand "like well-armed men in the inner stronghold of the mind ready to sally forth and overcome or make serviceable whatever shows itself at the portals of sense." It is then through the active aid of familiar ideas that new things find an introduction to soul life. If old friends go out to meet the strangers and welcome them, there will be an easy entrance and a quick adoption into the new home.
But frequently these old friends who stand in the background of our thoughts must be awakened and called to the front. They must stand as it were on tiptoe ready to welcome the stranger. For if they lie asleep in the penetralia of the home the new comers may approach and pass by for lack of a welcome. It is often necessary, therefore, for the teacher to revive old impressions, to call up previously acquired knowledge and to put it in readiness to receive and welcome the new. The success with which this is done is often the difference between good and poor teaching.
We might suppose that when two persons look at the same object they would get the same impression, but this is not true at all. Where one person faints with fright or emotion another sees nothing to be disturbed at. Two travelers come in sight of an old homestead. To one it is an object of absorbing interest as the home of his childhood; to the other it is much like any other old farm house. What is the cause of this difference? Not the house. It is the same in both cases. It is remarkable how much color is given to every idea that enters into the mind by the ideas already there. Some visitors at the World's Fair can tell almost at a glance to what states many of the buildings belong; other visitors must study this out on the maps and notices. One who is familiar with the history, architecture, and products of the different states is able to classify many of the buildings with ease. His previous knowledge of these states interprets their buildings. Mt. Vernon naturally belongs to Virginia, Independence Hall to Pennsylvania, John Hancock's house to Massachusetts. In a still more striking manner, a knowledge of foreign countries enables the observer to classify such buildings as the French, the German, the Swedish, the Japanese, etc. Again, in viewing any exhibit our enjoyment and appreciation depend almost entirely upon our previous knowledge, not upon our eye-sight or our physical endurance. Many objects of the greatest value we pass by with an indifferent glance because our previous knowledge is not sufficient to give us their meaning.
If a dry goods merchant, a horse jockey, and an architect pass down a city street together, what will each observe? The merchant notices all the dry goods stores, their displays, and their favorable or unfavorable location. The jockey sees every horse and equipage; he forms a quiet but quick judgment upon every passing animal. The architect sees the buildings and style of construction. If in the evening each is called upon to give his observations for the day, the jockey talks of horses and describes some of the best specimens in detail; the merchant speaks of store-fronts and merchandise; the architect is full of elevations of striking or curious buildings. The architect and merchant remember nothing, perhaps, about the horses; the jockey nothing of stores or buildings. Three people may occupy the same pew in a church; the one can tell you all about the music, the second the good points in the sermon, and the third the style and becomingness of the bonnets and dresses. Each one sees what he has in his own mind. A teacher describes Yosemite Valley to a geography class. Some of the children construct a mental picture of a gorge with steep mountain sides, but no two pictures are alike; some have mental pictures that resemble nothing in heaven above or earth below; some have constructed——nothing at all! only the echo of a few spoken words. If the teacher, at the close of her description, could have the mental state of each child photographed on the blackboard of her schoolroom she would be in mental distress. In presenting such topics to children, much depends upon the previous content of their minds, upon the colors out of which they paint the pictures.
We are now prepared for a more accurate definition of apperception. "The transformation of a newer (weaker) concept by means of an older one surpassing the former in power and inner organization bears the name of apperception, in contrast to the unaltered reception of the same perception." (Lindner's Psychol. p. 124, trans. by De Garmo.) Lindner remarks further, "Apperception is the reaction of the old against the new—in it is revealed the preponderance which the older, firmer, and more self-contained concept groups have in contrast to the concepts which have just entered consciousness." Again, "It is a kind of process of condensation of thought and brings into the mental life a certain stability and firmness, in that it subordinates new to older impressions, puts everything in its right place and in its right relation to the whole, and in this way works at that organic formation of our consciousness which we call culture." (Lindner p. 126.) "Apperception may be defined as that interaction between two similar ideas or thought-complexes in the course of which the weaker, unorganized, isolated idea or thought-complex is incorporated into the richer, better digested, and more firmly compacted one." (Lange, Apperception, p. 13.)
Oftentimes, therefore, older ideas or thought masses, being clear, strong, and well-digested receive a new impression to modify and appropriate it. This is especially true where opinions have been carefully formed after thought and deliberation. A well-trained political economist, for example, when approaching a new theory or presentation of it by a George or Bellamy, meets it with all the resources of a well-stored, thoughtful mind; and admits it, if at all, in a modified form to his system of thought. Sometimes, however, a new theory, which strikes the mind with great clearness and vigor, is able to make a powerful assault upon previous opinions, and perhaps modify or overturn them. This is the more apt to be the case if one's previous ideas have been weak and undecided. In the interaction between the old and new the latter then become the apperceiving forces. Upon the untrained or poorly-equipped mind a strong argument has a more decisive effect than it may justly deserve. As we noticed above, new ideas, especially those coming directly through the senses, are often more vivid and attractive than similar old ones. For this reason they usually occupy greater attention and prominence at first than later, when the old ideas have begun to revive and reassert themselves. Old ideas usually have the advantage over the new in being better organized, more closely connected in series and groups; and having been often repeated, they acquire a certain permanent ascendency in the thoughts. In this interaction between similar notions, old and new, the differences at first arrest attention, then gradually sink into the background, while the stronger points of resemblance begin to monopolize the thought and bind the notions into a unity.