It is the basis of many hypnotic phenomena.
In the field of pathology, memory, through its perversions, takes part in and helps to determine the form of a variety of disturbances such as obsessions, impulsions, tics, habit psychoses and neuroses, many of the manifestations of that great protean psychosis, hysteria, and other common ailments which it is the fashion of the day to term neurasthenia and psychasthenia. It is largely responsible for the conscious and subconscious conflicts which disrupt the human mind and result in various pathological states.
Finally, upon the utilization of the processes of memory modern psychotherapeutics, or the educational treatment of disease, is largely based. For many of these reasons an understanding of the mechanism of memory is essential for an understanding of the subconscious. In short, memory furnishes a standpoint from which we can productively study the normal and abnormal processes of the mind—conscious and subconscious.
These somewhat dogmatic general statements—which I have put before you much after the fashion of the lawyer who presents a general statement of his case in anticipation of the evidence—I hope will become clear and their truth evident as we proceed; likewise, their bearing upon the facts of abnormal psychology. To make them clear it will be necessary to explain in some detail the generally accepted theory of memory as a process and to cite the numerous data upon which it rests.
There may be, as, indeed, you will find there are, wide differences of opinion as to the exact psychological mechanism by which a memory-process plays its part in the larger processes of mental life, normal and abnormal, such as I have just mentioned, but that the memory-process is a fundamental factor is revealed by whatever method the problems are attacked. A study, therefore, of this fundamental factor and a determination of its mechanism are a prerequisite for a study of the more complex processes in which it takes part. For this reason I shall begin the study of the Unconscious (subconscious), to which I shall ask your attention in these lectures, with a consideration of the processes of memory.
If you ask the average person, as I have often done, how or why he remembers he will be puzzled and he is apt to reply, “Why, I just remember,” or, “I never thought of that before.” If you push him a bit and ask what becomes of ideas after they have passed out of mind and have given place to other ideas, and how an idea that has passed out of mind, that has gone, disappeared, can be brought back again as memory, he becomes further puzzled. We know that ideas that have passed out of mind may be voluntarily recalled, or reproduced, as memory; we may say that meantime they have become what may be called dormant. But surely something must have happened to enable these conscious experiences to be conserved in some way and recalled. Ideas are not material things which, like books, can be laid away on a shelf to be taken up again when wanted, and yet we can recall, or reproduce, many ideas when we want them just as we can go to a shelf and take down any book we want.
We learn the alphabet and the multiplication table in childhood. During the greater part of our lives the sensory images, auditory language symbols, etc., which may be summarized as ideas representing these educational experiences, are out of our minds and do not form a continuous part of our conscious experiences, but they may be recalled at any moment as memory. In fact, try as hard as we may, we cannot forget our alphabet or multiplication table. Why is this?
The older psychology did not bother itself much with these questions which puzzle the average man. It was content for the most part with a descriptive statement of the facts of conscious memory. It did not concern itself with the process by which memory is effected; nor, so long as psychology dealt only with phases of consciousness, was it of much consequence. It has been only since subconscious processes have loomed large in psychology and have been seen to take part on the one hand in the mechanism of conscious thought and on the other to produce various bodily phenomena, that the process of memory has acquired great practical importance. For it has been seen that in these subconscious processes previous conscious experiences are resurrected to take part as subconscious memory, consequently a conscious experience that has passed out of mind may not only recur again as conscious memory, but may recur subconsciously below the threshold of awareness. The study of subconscious processes therefore necessarily includes the processes of memory. And so it has become a matter of considerable moment to follow the fate of experiences after they have passed out of mind with a view to determining the mechanism by which they can be reproduced consciously and subconsciously. More than this it is important that the theory of memory should be removed if possible from the domain of purely speculative psychological concepts and placed on a sound basis of observation and experiment like other accepted theories of science.
From the point of view of animism, and indeed of dualism, nothing becomes of the ideas that have passed out of mind; they simply, for the time being, cease to exist. Consciousness changes its form. Nothing is preserved, nothing is stored up. This is still the popular notion according to which a mental experience at any given moment—the content of my consciousness, for instance, at this moment as I speak to you—is only one of a series of kaleidoscopic changes or phases of my self-consciousness. In saying this what is meant plainly must be that the content of consciousness at any given moment is a phase of a continuing psychical something. We may, perhaps, call this my self-consciousness, and say that when I reproduce an experience as memory I simply bring back (by the power of self-determination) that same previous phase of the psychical something. If I cannot bring it back my failure may be due to a failure of the power of self-determination or—and here is a weak point—to a failure in the formative cohesion of the elementary ideas of that experience. In this latter alternative no note is taken of a seeming contradiction paradox. If nothing is preserved, if nothing continues to exist, if memory is only one of a series of kaleidoscopic phases of consciousness, how can there be any cohesion or organization within what does not exist? Consciousness according to this notion might be likened to the water of a lake in which vortices were constantly being formed, either by the current of inflowing springs from the bottom or the influences of external agencies. One vortex would give place to a succeeding vortex. Memory would be analogous to the reproduction of a previously occurring vortex.
When, however, such a notion of memory is examined in the light of all the facts which have to be explained it will be found to be descriptive only of our conscious experiences. It does not explain memory; it does not answer the question of the ordinary man, “How can ideas which have ceased to exist be reproduced again as memory?” For, putting aside various psychological difficulties such as, How can I determine the reproduction of a former phase of consciousness—that is, memory—without first remembering what I want to determine?, or, if this be answered, “By the association of phases (ideas),” how can there be any bond of association between an existing idea and one that does not exist?, and, therefore, how can association bring back that which has ceased to exist?—putting aside such questions, there are a number of psycho-physiological facts which this conception of memory will be found inadequate to meet. As a matter of fact, investigations into the behavior of mental processes, particularly under artificial and pathological conditions, have disclosed certain phenomena which can be adequately explained only on the supposition that ideas as they pass out of mind—the mental experiences of the moment—leave something behind, some residuum which is preserved, stored up as it were, and which plays a subsequent part in the process of memory. These phenomena seem to require what may be called a psycho-physiological theory of memory. Although the theory has long been one of the concepts of normal psychology it can be said to have been satisfactorily validated only by the investigations of recent years in abnormal psychology.