Popular Science Monthly/Volume 48/January 1896/Suggestibility, Automatism, and Kindred Phenomena II
|SUGGESTIBILITY, AUTOMATISM, AND KINDRED PHENOMENA.|
THERE is another deduction from the doctrine of parallelism which has been much disputed but which seems to me legitimate. I know that when I glance up from my paper, see a pen, reach out and take it, ether waves which fell upon the retina of my eye produced there chemical changes which irritated the optic nerve; the irritation was transmitted to the visual centers of the brain, thence propagated to the motor centers, and from the motor centers went an impulse which contracted the muscles of my arm. But I am not directly conscious of all this. It seems to me that the conscious state which I call the perception of the pen caused the thought of the movement and the movement itself at almost the same time. Now, if we believe that every conscious state which we know has its physical concomitant of which we know nothing save by inference, I see no reason why we may not, for the time at least, ascribe directly to the mental states the properties which we believe belong in all strictness to their physical bases only. Thus, I think it correct to say that the perception of the pen awakened the thought of taking it and that that in turn produced the movement. Yet in using this form of speech we must guard against certain erroneous inferences which are frequently drawn from it. The first is that the perception of the pen was the only cause of the thought of taking it, and so on. We now know that the whole sequence which I have described depends for its existence and development upon the constitution of the total system of processes. This we are apt to forget, when we deal with the mental only, for the law of attention prevents any but a small portion of those processes obtaining clear recognition in consciousness at any one time: the remainder affect the clearest portion more or less, but exist themselves only dimly in the marginal region to which I am not attending. Again, we must not suppose that in ascribing to the mental state active properties we mean to imply that the mental states could exist or manifest those properties apart from the physical processes which form their basis, or that they can act upon them in any way from outside, as the older psychology supposed. I do not think, as most psychologists do, that this notion is inconsistent with the doctrine of parallelism, but it certainly can not be derived from it, or from the facts upon which it rests. Guarding against these two errors, then, we may justly regard the mental state as an active, dynamic thing, subject to laws and possessed of properties into which it is the business of the psychologist to inquire.
We all know the difference between red as seen and red as we think it, although the difference is hard to describe. In most persons the sensation red is peculiarly intense and vivid, while the idea is lacking in some indescribable way in both these traits. Now, we have reason to believe that both mental states are of the same general kind, and that the idea is capable of passing into a state indistinguishable from the sensation. Such a transition is known as development. In some persons certain ideas are normally already developed, so to speak, to their maximum degree. A friend of mine tells me that, so far as vividness and intensity go, it makes little difference to him whether his eyes are open or shut—what he sees is about the same in either case. But more commonly the idea must be much heightened before it reaches sensational intensity. Another friend of mine by thinking intently of a friend's appearance can see that friend slowly taking shape, at first as a shadowy outline, then gaining in clearness and solidity until the shadowy outline has become the perfect form of a real person. Now, if we regard the dimmest idea as zero and the clear sensation as the maximum, we may say that any mental state may conceivably run through all the intervening grades, and we have reason to believe that every mental state tends to run through some grades. This I would express by saying that every mental state tends to develop within limits which we can not at present assign. The first property of the mental state, then, is that of development. It is of importance in explaining the phenomena of dreams and hallucinations.
The second group of properties which I shall mention depend upon the transmissibility of the physical impulse. I have already shown in my first paper how mental elements become agglutinated into systems in which any one tends to awaken the others. It is also true of the relation of any one system to another; they tend to awaken one another. This is what is commonly described as association of ideas. The reverse is also true, although not as well known; many states tend to prevent the appearance of other states. Agreeable states, for example, tend to force out the disagreeable, and vice versa. This, then, may be generalized in the statement of the second property of mental states: every mental state tends to produce, or prevent the production of, other states. We may suppose that these phenomena are due to the interplay of systems of activities within the cortex with one another.
But these activities within the cortex which underlie our ordinary life of sensation and thought tend also to discharge downward through the Rolandic region into the motor mechanism, producing contractions of the muscles. Thus the third property of the mental state is the ability to produce or prevent muscular contraction. Not all mental states have this property in the same degree. It is most evidently true of the feeling of movement. I once asked a class of sixteen girls to think intently what it would feel like to lift the right hand and touch the left shoulder. After a few minutes had elapsed nine of them confessed having felt a desire to do it. I then dropped the subject and spoke of something else: in a few moments six actually did it. Most persons when concentrating attention upon the thought of what a given movement would feel like, find themselves becoming possessed of a desire to do it, and this desire marks the tendency of the thought to produce the movement. But as we not only feel but also see our movements, we find that the thought of what a movement looks like has also motor value and tends to produce it. This is also true of touches and ideas of touch—indeed, all or nearly all mental states produce some motor changes in the body, but the motor effects of sensations and ideas of sound, taste, and smell are relatively slight.
Again, mental states tend to help or hinder the processes of secretion and nutrition. We all know that the secretions of the salivary glands, of the kidneys, of the mammary, and other glands are readily affected by many mental states, but their effect upon the processes of nutrition is more disputed. It is quite certain that in a general way the impulses sent out by the central nervous system are necessary to the proper nutrition of the body, but it is not as generally accepted that individual mental states can produce definite changes, as, for example, when it is reported that a hypnotized patient, by thinking of a burn, has actually produced the burn. Yet even for this there is good evidence.
One may justly ask how it is, if mental states really have definite consequences, that we fail to note in our mental life the orderly sequence of cause and effect with which we are familiar in the physical world? If there be any truth in the theory above outlined, this inability to observe it is precisely what one should expect. It is not possible to analyze the total content of consciousness into any definite number of "states." The total state of consciousness at any given moment depends upon the condition and character of a system of physical activities, and its few distinguishable elements are related to some rather than to other elements of that system. But no portion of the system could be what it is if the other portions were not just what they are, and in the succession of the clearer states of consciousness we see not merely the effect of the one clear state upon the next clear state, but the effect of one whole system upon the next whole system; and often the active factor in determining the character of the next clear state is not what was clearest in the preceding, but one of those which were dimly existent in the margin, or even one of those that were subconscious. To determine the true properties of any state it would be necessary to isolate it by breaking up this co-ordination, and that, as I shall show later, we can to some extent do.
Before taking up these more complex forms of disorganization, or, better, disordination, I must make plain the meaning of the word subconscious, which I have had occasion once or twice to use.
I am sitting in a chair and reading an interesting story; the clock strikes and I do not hear it. Why? There are only four possible theories. We must suppose that the air vibrations strike the ear drum and are propagated through the ear bones and lymph to the auditory nerve. Then either (1) the physical process is blocked at some point between the terminal filaments of the auditory nerve in the inner ear and its origin in the cortex; or (2) the irritation reaches the cortex, but fails to awaken any cortical process; or (3) it awakens a cortical process which is unaccompanied by any mental state; or (4) it awakens both a cortical process and a mental state. For the first of these alternatives there is no evidence. On the contrary, since I hear the clock strike if I am expecting it, and since all theories require us to regard expectation as dependent upon cortical processes, if any mental phenomena are, we must look to the cortex for the explanation and not to the peripheral machinery. The second alternative is conceivable, but there is no direct evidence for it and there is some against it. It is frequently possible, for example, to awaken by hypnotic suggestion a memory of the event which was not consciously experienced, and, as memory depends upon the traces left by earlier experiences in the cortex, it would seem to follow that there must have been a cortical disturbance. The third alternative is more probable. There is reason for believing that any cortical process must attain a certain degree of intensity before its mental concomitant comes into being at all, and perhaps the existence of other active processes prevents its attaining that degree of intensity. Again, if we revert to the old soul theory, now almost wholly abandoned by psychologists, but still, I think, worthy of consideration, we may suppose that the cortical process alone can not produce consciousness, but requires the co-operation of some other factor. The pros and cons in these last two suppositions are too intricate for present discussion, and, indeed, my purpose is, not to prove a theory, but to state the fourth supposition and to analyze some of its logical implications.
The parallel theory would raise the presumption that any cortical process is accompanied by mental phenomena of some kind. We would then assume, in the case under consideration, that the cortical process in the auditory center generated a sound. But how is this to be reconciled to the testimony of consciousness that I heard no sound?
Well, it may be that I did hear it, but instantly forgot it, so that my present memory of that period contains no trace of it. That this frequently happens there can be no doubt, but there are many curious phenomena which require a further assumption, and that further assumption may be thus stated: The sound may have existed simply as a solitary sound, all alone, not in my consciousness or in the consciousness of any one, but as a bare mental event, related to my consciousness much as a sound in your consciousness is related to mine. It is not an easy conception to grasp, for our mental life always consists of many elements, and it would seem that this multiplicity is essentially involved in our notion of consciousness. Yet occasionally we have experiences which help us in forming the conception of a mental state existing outside a personal consciousness. I remember a trifling operation upon the eye which I once underwent. For a few seconds my consciousness seemed reduced to one element—a flood of frightful pain, which was not in my eye but seemed to pervade my whole being, to the almost complete exclusion of all else. Again, under nitrous oxide, my consciousness seemed reduced to something so rudimentary as to be wholly indescribable. I have heard of many similar experiences.
Without pronouncing upon the relative merits of the last two hypotheses I shall develop some of the logical implications of the latter. A state such as I have described, supposed to exist within my head, so to speak, but outside my consciousness, may be described as subconscious. There are, then, two conceivable ways in which a mental state may vanish from the upper consciousness. The cortical process upon which it depends may die away; it then perishes absolutely; or the cortical process may be dissociated from the system underlying the total consciousness and yet remain active, thus giving rise to a subconscious state. This supposition, that a cortical process may exist without coalescing at all with the general system, is a somewhat novel assumption, and it is in my opinion the weakest point of the theory. It would require the further assumption that a cortical system, once coordinated, tends to resist the introduction of a new element into it, and for this there is some introspective evidence.
For consistency's sake the dynamic conceptions which I would apply to mental states in consciousness must be applied also to these mental states existing subconsciously. Subconscious ideas and sensations must be capable of development in intensity and in perfection of finish, so to speak; must be able to awaken associated ideas, to produce bodily movements, to affect secretion and other metabolic processes. It would appear possible that the dissociated processes underlying them may suddenly effect union with the upper system, thus intruding the subconscious state into the upper consciousness. When it does not actually effect union it is conceivable that some of its results, such as its associated ideas or emotional consequents, may appear in the upper consciousness. It is also conceivable that its mere existence may disturb the normal tension of the cortical activities, what has been termed the psychostatic equilibrium of the cortex, and thus affect the upper consciousness. A mental state supposed to be thus growing and working subconsciously has been happily termed by Pierre Janet a mental parasite or neoplasm. For all these inferences, which I have stated as deductions from the hypothesis that there exist mental states dissociated from the normal consciousness, there is a great deal of direct evidence, and it is upon an inductive study of that evidence that the hypothesis is based; but the limitations of space prevent my giving concrete illustrations.