Registration.—By registration we mean the learning or committing of the matter to be remembered. On the brain side this involves producing in the appropriate neurones the activities which, when repeated again later, cause the fact to be recalled. It is this process that constitutes what we call "impressing the facts upon the brain."
Nothing is more fatal to good memory than partial or faulty registration. A thing but half learned is sure to be forgotten. We often stop in the mastery of a lesson just short of the full impression needed for permanent retention and sure recall. We sometimes say to our teachers, "I cannot remember," when, as a matter of fact, we have never learned the thing we seek to recall.
Retention.—Retention, as we have already seen, resides primarily in the brain. It is accomplished through the law of habit working in the neurones of the cortex. Here, as elsewhere, habit makes an activity once performed more easy of performance each succeeding time. Through this law a neural activity once performed tends to be repeated; or, in other words, a fact once known in consciousness tends to be remembered. That so large a part of our past is lost in oblivion, and out of the reach of our memory, is probably much more largely due to a failure to recall than to retain. We say that we have forgotten a fact or a name which we cannot recall, try as hard as we may; yet surely all have had the experience of a long-striven-for fact suddenly appearing in our memory when we had given it up and no longer had use for it. It was retained all the time, else it never could have come back at all.
An aged man of my acquaintance lay on his deathbed. In his childhood he had first learned to speak German; but, moving with his family when he was eight or nine years of age to an English-speaking community, he had lost his ability to speak German, and had been unable for a third of a century to carry on a conversation in his mother tongue. Yet during the last days of his sickness he lost almost wholly the power to use the English language, and spoke fluently in German. During all these years his brain paths had retained the power to reproduce the forgotten words, even though for so long a time the words could not be recalled. James quotes a still more striking case of an aged woman who was seized with a fever and, during her delirious ravings, was heard talking in Latin, Hebrew and Greek. She herself could neither read nor write, and the priests said she was possessed of a devil. But a physician unraveled the mystery. When the girl was nine years of age, a pastor, who was a noted scholar, had taken her into his home as a servant, and she had remained there until his death. During this time she had daily heard him read aloud from his books in these languages. Her brain had indelibly retained the record made upon it, although for years she could not have recalled a sentence, if, indeed, she had ever been able to do so.
Recall.—Recall depends entirely on association. There is no way to arrive at a certain fact or name that is eluding us except by means of some other facts, names, or what-not so related to the missing term as to be able to bring it into the fold. Memory arrives at any desired fact only over a bridge of associations. It therefore follows that the more associations set up between the fact to be remembered and related facts already in the mind, the more certain the recall. Historical dates and events should when learned be associated with important central dates and events to which they naturally attach. Geographical names, places or other information should be connected with related material already in the mind. Scientific knowledge should form a coherent and related whole. In short, everything that is given over to the memory for its keeping should be linked as closely as possible to material of the same sort. This is all to say that we should not expect our memory to retain and reproduce isolated, unrelated facts, but should give it the advantage of as many logical and well grounded associations as possible.
Recognition.—A fact reproduced by memory but not recognized as belonging to our past experience would impress us as a new fact. This would mean that memory would fail to link the present to the past. Often we are puzzled to know whether we have before met a certain person, or on a former occasion told a certain story, or previously experienced a certain present state of mind which seems half familiar. Such baffling mental states are usually but instances of partial and incomplete recognition. Recognition no longer applies to much of our knowledge; for example, we say we remember that four times six is twenty-four, but probably none of us can recall when and where we learned this fact—we cannot recognize it as belonging to our past experience. So with ten thousand other things, which we know rather than remember in the strict sense.
3. THE STUFF OF MEMORY
What are the forms in which memory presents the past to us? What are the elements with which it deals? What is the stuff of which it consists?
Images as the Material of Memory.—In the light of our discussion upon mental imagery, and with the aid of a little introspection, the answer is easy. I ask you to remember your home, and at once a visual image of the familiar house, with its well-known rooms and their characteristic furnishings, comes to your mind. I ask you to remember the last concert you attended, or the chorus of birds you heard recently in the woods; and there comes a flood of images, partly visual, but largely auditory, from the melodies you heard. Or I ask you to remember the feast of which you partook yesterday, and gustatory and olfactory images are prominent among the others which appear. And so I might keep on until I had covered the whole range of your memory; and, whether I ask you for the simple trivial experiences of your past, for the tragic or crucial experiences, or for the most abstruse and abstract facts which you know and can recall, the case is the same: much of what memory presents to you comes in the form of images or of ideas of your past.
Images Vary as to Type.—We do not all remember what we call the same fact in like images or ideas. When you remembered that Columbus discovered America in 1492, some of you had an image of Columbus the mariner standing on the deck of his ship, as the old picture shows him; and accompanying this image was an idea of "long agoness." Others, in recalling the same fact, had an image of the coast on which he landed, and perchance felt the rocking of the boat and heard it scraping on the sand as it neared the shore. And still others saw on the printed page the words stating that Columbus discovered America in 1492. And so in an infinite variety of images or ideas we may remember what we call the same fact, though of course the fact is not really the same fact to any two of us, nor to any one of us when it comes to us on different occasions in different images.