The Foundations of Normal and Abnormal Psychology/Appendix II
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Appendix II - Physiological Traces
My attention was called to a very valuable paper "Further Studies in the Chemical Dynamics of the Central Nervous System," by T. Brailsford Robertson, published in the "Folio Neuro-Biologica" Band VII, 1913. Robertson advances an extremely interesting hypothesis based on his bio-chemical researches. Basing himself on the fact that "the performance of mental work initially facilitates its further performance and subsequently depresses or fatigues it," he builds up a far reaching chemico-physiological hypothesis of the main phenomena of normal and abnormal mental life. I quote freely from his paper as it is of importance and highly stimulating to those who wish to go into the more technical scientific details of physiological research in regard to the phenomena of normal and abnormal mental function.
"We meet therefore in the exercise of a given intellectual function with two apparently contradictory facts. Performance facilitates the exercise of the function and it likewise depresses the exercise of the function. We note furthermore that the facilitation and depression become evident at different periods of time, the former in the earlier and the latter in the later stages of performance. Now this phenomenon is not at all limited to the functions of the central nervous system. It is displayed in a very striking way by the variety of other functions, for instance in the contraction of the muscles in response to stimulation, whether direct or indirect. The phase of facilitation is displayed initially in the well known 'staircase phenomenon' and the phase of depression by rigidity and inability to contract to stimuli in response to stimuli which formerly evoked a maximal response. Again, as I have shown in a series of communications, a similar phenomenon is displayed in growth which initially undergoes acceleration and therefore slows down. Indeed acceleration and slowing may alternate a number of times in the same organism producing what I have termed 'growth cycles.' This type of phenomenon would appear very generally displayed in the performance of life-activities, and indeed I am inclined to think with Loeb that the self conserving character of the life-process will ultimately find its solution in the study of phenomena of this description."
This principle of "growth cycles" is significant, inasmuch as it falls in the line with the fundamental principle of reserve energy developed by James and myself from different standpoints.
Robertson assumes the presence of physiological traces. "If the central nervous system conditions these phenomena at all, as we believe it does, then the passage of a stimulus through the central nervous system must lead through a changed condition which for the sake of forming a concrete image we may term in the language employed by Maudsley, the desposition of a trace or in the terminology of Exner, the excavation of a channel (Bahnung) . . . The dynamic conception of trace formation regards it as being due to a chemical alteration of cell-material along the path of the trace." We have seen that trace formation is at first facilitated by the process which brings it about and later depressed. . . . At first a stimulus passes over the 'trace' more readily, because it has previously done so, but at a later stage it passes over it less and less readily until finally the resistance is so great as to almost inhibit its passage altogether. Recalling this fact we find ourselves in a position to crystallize our problem and state it in the following terms: 'What is the nature of a chemical reaction which at first takes place the more readily in consequence of having previously taken place, but at a later stage is inhibited by its own progress?' When this question is addressed to a physical chemist he does not hesitate in replying: 'The reaction is either catenary (consists of two reactions the second of which uses up the production of the first) or it is autocatalytic, i.e., one of the products of the reaction accelerates the reaction.' No other chemical reactions are known to the experience of the chemist which displays at any stage positive acceleration."
The various experimental works carried out by Robertson lead him to the rejection of catenary reactions and to the assumption of autocatalysis. Basing himself on this hypothesis of autocatalysis Robertson goes on to explain from a purely chemico-physiological standpoint the phenomena of memory, amnesia, of hypnosis and of applied phenomena.
"Adopting the working hypothesis outlined above, we perceive that the canalisation hypothesis of Exner can now be expressed in a much more definite and concrete form. Each incoming stimulus carves out for itself in the central nervous system or deepens a pre-existing channel in the central nervous system, but channel is not a trough formed by the physical displacement of particles, it is a chemical channel, a thread or trace of the autocatalyst of central nervous activities, a thread which need not necessarily be supposed to be more than a few times the diameter of 'the sphere of molecular influence' in width. This deposit necessarily follows faithfully the path pursued by the original impulse and permits succeeding impulses to pass over the same path more readily by virtue of its presence. It is possessed of course of a definite spatial location, but, and this is a very important point, if by any chance it should be obliterated or destroyed it is not irreplaceable even if the continuity of the original path be forever interrupted. For it is only one of a conceivably enormous number of paths which might be traversed by a stimulus in its passage from one extremity of the original path to the other. Furthermore, the trace is capable of being traversed by other subsequent or performed traces in as many different ways as the axons and ganglion cells of the central nervous system intercommunicate, that is, so far as our knowledge extends, in a number of ways which for all practical purposes may be regarded as infinite.
"It must always be remembered that the trace consists of a deposit of an autocatalyst which we are obviously compelled to assume is an autocatalyst for the propagation of all impulses. It follows, therefore, that if a faint trace runs into, that is to say, traverses or intersects a well-marked trace, there will be a tendency for the impulse forming or following the faint trace to be deflected completely at or in a great part into the well marked trace. Indeed if the intersecting trace be sufficiently well marked and formed subsequently to the faint trace, we can see how impulses now arriving by way of the faint trace remote from the point of intersection almost untraversed by any impulses at all. Instances of the mental correlates of these physico-chemical phenomena abound in our daily psychic life."
In our next book on "Symptomatology" we shall refer to Robertson's application of his theory to the various phenomena of hypnosis, multiple personality, amnesia and various forms of dissociation. I wish here to call attention to Robertson's valuable paper and point out his relation to the hypothesis of unconscious cerebration on the one hand and to my psycho-biological doctrines of the moment-consciousness on the other.
Robertson fully realizes the shortcomings and crudeness of the physiological theories advanced by many physiologists to the effects of crowding out mental phenomena or consciousness, the very phenomena which the physiological theories were constructed to explain physiologically or rather to follow out physiologically step by step. As I have insisted in this volume a physiological correlative must be postulated for all phenomena of consciousness. This however is far from denying the mental facts themselves and thus being left with a physiological hypothesis instead of the facts themselves for which this hypothesis was constructed. When a physiologist or biologist constructs a physiological hypothesis as a correlative of consciousness he is so carried away with it that he soon forgets the purpose of the hypothesis and proceeds to deny the main facts. From a purely scientific we must postulate that each and every act of experience, of consciousness has a physiological correlative, a point on which I have laid special stress. The reasoning of a Newton, Aristotle, and Plato as well as the moral thoughts and feelings of prophets and saints have their physiological correlatives. This however would not mean that all those experiences of genius, intellectual and moral, are unconscious cerebrations devoid of all conscious awareness. Under such conditions it is best to stick to the facts and regard the physiological hypothesis as a pretty speculation which may do more harm than good, inasmuch as it distracts the attention from the facts at issue.
What I claim is that a good deal, if not the most of what is described as subconsciousness, is essentially of the same inner, subjective experience of what we otherwise describe as conscious awareness, inasmuch as introspective experience, both direct and indirect, given by immediate experience and by memory, as well as by reactions and behavior are the same as found in fully conscious states. If we deny awareness to subconscious manifestations, such as hypnosis and allied states, we should also call in question the awareness of all other similar states. It goes without saying as I have pointed that hypnosis and allied states being phenomena of consciousness must have a physiological correlative, but it is still to be proven that in such states there is only a physiological process without any conscious accompaniment. We may as well claim that the Illiad, Hamlet, Principia, the Parthenon, Venus de Milo and other creations of genius are the result of physiological processes. In a certain sense the claim is true, there is a physiological correlative to the highest flight of genius, but it is manifestly absurd to omit the conscious elements that go to constitute the very essence of what we regard as genius. Conscious and subconscious phenomena have alike physiological correlatives and both of them are characterized by consciousness, awareness, and feeling. The subconscious is a conscious, an other-consciousness, a consciousness other than the usual personal consciousness.
Robertson is fully aware not only of the crude attempts of what he terms static physiological theories, but also of the fallacy of denying consciousness and installing in its place physiological currents, traces, and deposits. "It must be admitted" he says, "that the sporadic attempts which have been made from time to time by biologists to advance interpretations of the physical correlates of psychic phenomena have seldom been either well judged or attended by any measure of success." In another place he says; "The static conception as that developed by Munk and Ziehen, regards the ‘trace’ as some structural modification, some physical alteration, an alteration in other words in the distribution of cell-matter space. I have elsewhere dwelt rather at length upon the more manifest objections to this point of view, at least in the crude form in which it has hitherto been presented. It would require each idea, mental image and conception to be very strictly localized. Such a localization of ideas has, of course, never been demonstrated."
The "trace" is conceived by Robertson in dynamic terms. This dynamic "trace," the correlative of memory, conscious and subconscious, is more or less permanent, because "the persistence of memories proves the ‘trace,’ whatever it may be is rather permanent and only very slowly fades away."
Robertson fully realizes the importance of the subconscious for the conscious activity. "The phenomena of subconscious memory reveal clearly that memories may persist from childhood to advanced maturity without intermediate self-conscious recollection to reinforce the trace. Occasional subconscious recollection cannot of course be ruled out, but it must be rare in many cases, for otherwise, as Sidis has pointed out, our entire mental life would be occupied on recollecting."
In speaking of the static physiological theories Robertson says: "Sidis proceeds to dispose of all these theories collectively on the ground that a mere modification left behind as a trace cannot possibly explain, memory, recollection, the fact of referring a particular bit of experience to an experience felt before." Robertson fully sees the function of the physiological theories as correlatives of conscious states, not as substitutes. He realizes fully that the function of a good physiological theory of the physiological correlatives of conscious states is not the ruling out of the subjective phenomena which after all form the real material of investigation. He assumes the presence of consciousness as a datum to which he wishes to find a physiological correlative. "Such criticism" he goes on to say "is perfectly sound, if these theories are seriously advanced as ‘explanations’ (rather as substitutes as I would say considering the hypothesis of the subconscious advanced recently by some writers on the subject) of the subjective experience of memory. A subjective experience of recollection can no more be identified with a physical modification of a nerve element than the subjective experience of a given color can be identified with a particular wave length of light. But I submit that regarding memory from an objective standpoint as a pure objective fact (modification of the present as a result of previous reactions to stimuli) it demands objective interpretation with precisely the same force as any other objective fact."
That memory has physiological correlatives we must regard as one of the fundamental assumptions of psychology, both normal and abnormal. What I protest against is the metaphysical "Unconscious" which claims to take place of subjective facts. The Unconscious (with a capital U) as formulated by Carpenter, Ziehen and by other modern writers, under the belief and possibly with good intention of being more scientific, introduces Hartmanian metaphysics of the marvels of the Unconscious into psychic life. We must remember once and for all that "deposits of images in memory ganglion cells," "unconscious dispositions," "neurograms," and other kinds of figurative representations, are in the last resort figurative images which may help to picture the possibility of physiological correlatives of physic states, but they cannot, from their very nature, replace the real facts, the facts of consciousness. As soon as such claim is made by the "Unconscious" it must be declared to be what it really is, namely a speculative hypothesis of certain mental phenomena which alone constitute the real facts.
Perhaps it is in place to add a few words as to the hypothesis of autocatalysis in relation to what Robertson discusses as Sidis’ hypothesis of neuron disaggregation Robertson thinks that the theory of neuron disaggregation stated from the standpoint of neuron retraction should be abandoned. It seems to me however, that the theory of neuron disaggregation or of systematic neuron disaggregation does not depend on the theory of neuron retraction. The latter is provisional. Systems of functioning neurons may be thrown out of association due to changes of their thresholds. This rise and fall of threshold development in my Multiple Personality puts the hypothesis of neuron disaggregation on a more solid and more certain physiological basis.
In fact the rise and fall of thresholds of neuron systems may be very well stated in Robertson’s own hypothesis of autocatalysis. The theory of the rise and fall of thresholds is based on a series of known physiological and psychological facts. It is quite possible that the rise and fall of thresholds which gives rise to neuron disaggregations with its accompanying phenomena of dissociation are ultimately due to changes in the formation of systems of autocatalytic products. Should the latter hypothesis be proven I think the theory of neuron disaggregation would rest on a sure chemico-physioligcal basis.
The theory of neuron disaggregation may well be stated in Robertson’s theory of autocatalysis correlative with psychic phenomena. In fact, Robertson himself calls attention to the fact that his theory does not fundamentally clash with mine, the two may in fact be in full accord. "Abandonment of the postulate of neuron disaggregation," (rather neuron retraction) Robertson concludes his paper, "does not in the least involve, however, rejection of the really essential features of Sidis’ hypothesis of ‘moment consciousness.’ My hypothesis does not traverse the hypothesis of Sidis, it merely supplements it and renders necessary a readjustment of the physiological equivalents of his terminology. From Sidis’ point of view the full waking consciousness may be likened to a pyramid having for its base a greater or smaller number of ‘moment consciousness.’ From my point of view it may be likened to a complicated textile fabric built up out of the physical correlates of a greater or smaller number of interconnected traces. It is obvious that for the purpose of purely physiological analysis the two hypotheses are almost completely interchangeable; but for Sidis’ ‘moment consciousness’ we must read not ‘neurones,’ but ‘traces,’ ‘channels,’ or ‘deposits of autocatalyst.’"
The criticism passed on by Robertson’s theory that it fails to account for conservation of memory is unjustified. Robertson’s theory is fully adequate to explain conservation of memories.