Part 17

=Physiological memory and processes.=—There is one phase of the unconscious which for the sake of completeness ought to be touched upon here, particularly as it is of considerable importance in any biological conception of intelligence. _There is every reason to believe that_ intrinsically _there is no essential difference between those physiological dispositions and activities of the lower nervous centers (subcortical ganglia and spinal cord), which condition and determine unconscious behavior, and those dispositions and activities of the higher centers—the cortex—which condition and determine both conscious and unconscious behavior._ The former are undoubtedly innate in that they are primarily conditioned by inherited anatomical and physiological prearrangements of neurons and the latter are pre-eminently acquired through experience although probably not wholly so. (Our knowledge of the localization of function in the nervous system is not sufficiently definite to enable us to delimit the localization of either innate or acquired dispositions.) The innate activities of the lower nervous centers so far as represented by movements can be clearly differentiated from those of the higher centers and recognized in the behavior of so-called “spinal” animals and of animals from which the cerebral hemispheres have been removed. In the former the connection between the spinal cord and all parts of the nervous system above having been severed, whatever movements are executed are performed by the spinal cord alone and therefore of course by unconscious processes. The latter animals, although their actions are more complex and closely approximate (with important differences) those of normal animals, are also devoid or nearly devoid of consciousness. I say “nearly devoid” because in the interpretation of the experiments it is difficult to disprove that, as some hold, elementary sensations—qua sensation—are retained, though others regard the animals as purely unconscious physiological machines.

In the spinal animal, in response to specific stimuli, various movements are elicited which though of a purposive character are effected, as has been so admirably worked out by Sherington, by complex spinal mechanisms of a reflex character. The so-called “scratch reflex” and the reflex movements of walking, trotting, and galloping (the animal being suspended in air) are examples. Such reflexes involve not only the excitation of certain movements appropriate to the stimulus but the inhibition of antagonistic muscles and reflex movements. Further in the integration of the spinal system, reflexes are compounded, one bringing to the support of another allied accessory reflexes so that various coöperative movements are executed. A constellation of reflexes leads to quite complex spinal mechanisms responsive to groups of stimuli acting concurrently and resulting in behavior which is purposive and adaptive to the situation. The neural processes executing such movements are necessarily conditioned by inherited dispositions and structural arrangements of the neurons.

In the animal from which the cerebral hemispheres only have been removed there can be little doubt that the physiological mechanisms governing behavior differ only in complexity, not in kind, from those of the spinal reflexes; that in passing through successive anatomical levels from the spinal animal to this decerebrate animal with the addition of each successive ganglion the increasing complexity of behavior corresponds to increasing complexity of mechanisms or compounding of reflexes. And yet in the decerebrate animal without consciousness, as we must believe (excepting perhaps elementary sensations), the subcortical ganglia and spinal cord continue to perform exceedingly complex actions ordinarily, as we suppose, guided in the normal animal by consciousness. The reptile crawls; the fish swims; indeed the lancet fish has no brain, all its functions being regulated by its spinal cord. The frog hops and swims; the hen preens its feathers, walks and flies; the dog walks and runs. These, however, are the simplest examples of decerebrate behavior. Indeed it may be quite complex. The more recent experiments of Schräder on the pigeon and falcon and Goltz and Rothmann on the dog, not to mention those of earlier physiologists, have shown that the decerebrate unconscious (?) animal performs about all the movements performed by the normal animal.[123] “A mammal such as a rabbit, in the same way as a frog and a bird, may in the complete or all but complete absence of the cerebral hemispheres maintain a natural posture, free from all signs of disturbance of equilibrium, and is able to carry out with success at all events all the usual and common bodily movements. And as in the bird and frog, the evidence also shows that these movements not only may be started by, but in their carrying out are guided by and coordinated by, afferent impulses along afferent nerves, including those of the special senses. But in the case of the rabbit it is even still clearer than in the case of the bird that the effects of these afferent impulses are different from those which result when the impulses gain access to an intact brain. The movements of the animal seem guided by impressions made on its retina, as well as on other sensory nerves; we may perhaps speak of the animal as the subject of sensations; but there is no satisfactory evidence that it possesses either visual or other perceptions, or that the sensations which it experiences give rise to ideas.”[124]

Even _spontaneity_ which at one time was supposed to be lost it is now agreed returns if the animal is kept alive long enough. It “wanders about in the room untiringly the greater part of the day” (Loeb).

Of course there are differences in the animal’s behavior when compared with normal behavior, but these differences are not so easy to interpret in psychological terms. Loeb, apparently following Schräder, does not believe the animal is blind or deaf or without sensation for it reacts to light, to noise, to smell, to tactile impressions, etc. It avoids obstacles and is guided by visual impressions, etc. The falcon jumps at and catches a mouse introduced in its cage; the dog growls and snaps if its paw is pinched and endeavors to get away or bite the offending hand; the pigeon flies and alights upon a bar, apparently visually measuring distance, and so on. But though it is guided by visual and other sensory _impressions_, does it have visual, auditory and other _images_, that is, conscious sensory states? This is not easy to answer. It certainly acts like an animal that is not blind nor deaf nor without tactual sensation, and yet it is conceivable that it is guided simply by sensory mechanisms without conscious sensation. The main reason, apparently, for believing the animal to be without sensation, as some believe (e. g., Morgan) is the absence of the cerebral cortex in which alone sensation is believed to be “localized.” Recently Rothmann[125] has succeeded in keeping alive for three years a dog from which the entire cerebrum was extirpated. It was then killed. Although the dog, like Goltz’ dog, in its behavior exhibited an abundance of functions in the spheres of mobility, sensibility, feeding, barking, etc., Rothmann came to the conclusion that it was blind and deaf.[126] Although apparently without taste for bitter, sweet, sour, and acid, yet the dog reacted differently to edible and non-edible substances, swallowing the former and rejecting the latter (moist sand); raw flesh was eaten preferably to cooked flesh and Goltz’ dog rejected from its mouth food made bitter with quinine. Some kind of gustatory processes (probably purely reflex as in Pawlow’s association experiments) were therefore retained though not necessarily taste as such. But blindness and deafness in the dog cannot negative the retention in birds and other animals of visual and auditory impressions of some kind which guide and originate behavior. But whether such impressions are psychologically sensations or not, the animal certainly does not possess visual or other _perceptions_, because the “sensations” have no “meaning.” Schräder’s falcon, for example, would jump at and catch with its claws a moving mouse in the cage, but there the matter was at an end; it did not devour it as would a normal falcon. Any moving object had for it the same meaning as a mouse and excited the same movement. So the decerebrate dog does not distinguish friend from stranger and other dogs have no meaning for it. All objects are alike to all decerebrate animals. In the popular language of the street “all coons look alike” to them. In other words the main defect is loss of memory for conscious experiences, of what Loeb calls associative-memory, the conscious memory which gives meaning to sensations, transforms them by synthesis into _perception_ of objects and gives still further meaning to the objects. Hence for the pigeon without its cerebrum “Everything is only a mass in space, it moves aside for every pigeon or attempts to climb over it, just as it would in the case of a stone. All authors agree in the statement that to these animals all objects are alike. They have no enemies and no friends. They live like hermits no matter in how large a company they find themselves. The languishing coo of the male makes as little impression upon the female deprived of its cerebrum as the rattling of peas or the whistle which formerly made it hasten to its feeding place. Neither does the female show interest in its young. The young ones that have just learned to fly pursue the mother, crying unceasingly for food, but they might as well beg food of a stone.”[127]

One of the chief utilities of conscious memory is the means it offers the psycho-physiological organism to make use of past experiences to adapt present conduct to a present situation. This the brainless animal cannot do. Hence it is a mindless physiological automaton. All the actions performed by it, however complex they may be, are unquestionably performed and primarily conditioned by inherited neural arrangements and dispositions. They may be even regarded as complexly compounded reflex processes similar excepting in complexity, as Sherrington has held, to the mechanisms of the spinal cord. The behavior of the animal is therefore by definition instinctive. But even so this fact in no way throws light upon the intrinsic nature of the physiological process, but only upon the conditions of its occurrence. Acquired behavior is also conditioned—conditioned by acquired dispositions. The difference physiologically between the two is that in instinctive behavior the neural processes are confined to pathways established by evolutionary development, and in acquired behavior to pathways established by experience. Both must be conditioned by pathways, and the process in its inner nature must be the same in both. Many cortical processes, to be sure, are conscious—i.e., correlated with consciousness—but probably not all. And this quality of consciousness permitting of conscious memory is of great utility in the organization of acquired dispositions that provide the means for the adaption of the animal to each new environmental situation.

Furthermore, it is not at all certain that the behavior of the decerebrate animal is not in part determined by _secondarily acquired dispositions_. In the normal animal instinctive actions become modified and perfected after the very first performances of the act by conscious experience[128] and it is not at all certain that dispositions so acquired and essential for these modifications are not conserved and incorporated in the unconscious neural arrangements of the subcortical centers. So far as this may be the case the acquired modifications of instinctive behavior may be manifested in the actions of the decerebrate animals. In other words, the unconscious processes of the lower nervous centers motivating movements (and visceral functions) may include _acquired dispositions or physiological memories_.

That the subcortical centers are capable of memory seems to have been shown for the first time by Rothmann’s dog. This mindless animal proved to be capable of a certain amount of education. It learned to avoid hitting against objects, and to do certain tricks—jumping over a hurdle and following on its hind legs a stool upon which its fore feet were placed as the stool was dragged forward. “In the perfection of all these performances the influence of practice was easily recognized.” This means, if the interpretation given is correct, that new dispositions and new connections may be acquired within the lower centers _without the intervention of the integrating influence of the cortex_ or conscious intelligence.[129] This is an important contribution for apparently the attempt to educate brainless animals had not been previously made, and their capability for education demonstrated.

The important bearing which this fact has upon this discussion is that it shows that unconscious processes are capable of memory, that is physiological memory. It may be said that this statement needs some modification if the sensory “impressions” guiding the decerebrate animal are to be interpreted as true psychological, however elementary, “sensations.” It would seem to me on the contrary only to accentuate the fact that the processes of the brainless animal are on a transition level between the purely unconscious processes of the spinal animal and the purely (if ever wholly so) conscious processes of the normal animal, and that intrinsically all are of the same nature. If sensation enters into the complex reflex reactions of the brainless animal it would seem that it can only be an elemental conscious factor in a complicated unconscious physiological mechanism. In this mechanism it can have no more specific importance in determining behavior, because of the fact of its being a psychological state, than if it were a receptor “impression” intercalated in the arc of an innate process. It is not linked with any associative memories of the past or foresight into the future; it does not constitute conscious intelligence. As a conscious experience it cannot have that kind of “meaning” which in the normal animal modifies instinctive processes and determines conduct. It probably plays simply the same part in the whole process, which otherwise is wholly unconscious, that the associative sensory image plays in determining the flow of thick or thin saliva in Pawlow’s dogs—simply a single link in a chain of associated reflex processes.

The next point to which I would direct attention is that from an objective point of view the behavior of the decerebrate animal may be in nature _intelligent_ in the empirical sense of that word. The dog that growls and snaps when his foot is pinched, tries to draw it away, and, failing that, bites at the offending hand; the “educated” dog that jumps over a hurdle, and walks on his hind legs, following a stool supporting his front legs, to my way of thinking performs intelligent actions whether it has a brain or not. If intelligence is arbitrarily limited to actions performed by conscious processes, then intelligence becomes a mere question of terms.[130] There arises also the practical difficulty that certain types of behavior, which by common assent and common sense are regarded as purely automatic and unintelligent, must be termed intelligent because guided by consciousness. I cannot help thinking that “intelligence” is a pragmatic question, not a biological or psychological one. It would be much more conducive to a clear understanding of biological problems to use intelligence only as a convenient and useful expression, like sanity or insanity, to designate certain behavior which conforms to a type which, without strictly defining its limits, popular language has defined as intelligent. Sanity and insanity have ceased to be terms of scientific value because they cannot be defined in terms of specific mental conditions and much less in terms of mental processes. So intelligence cannot be defined in terms of conscious and unconscious processes. Any attempt to do so meets with insuperable difficulties and becomes “confusion worse confounded.” When we say then that the behavior of the decerebrate dog may be intelligent, all that is meant is that the animal exhibits behavior identical with that which in the normal animal we would empirically call intelligent. In this sense unconscious processes may exhibit intelligence. It was from this viewpoint, I think, that Foster concluded: “In short, the more we study the phenomena exhibited by animals possessing a part only of their brain, the closer we are pushed to the conclusion that no sharp line can be drawn between volition and lack of volition, or between the possession and absence of intelligence. Between the muscle-nerve preparation at one limit, and our conscious willing selves at the other, there is a continuous gradation without a break; we cannot fix on any linear barrier in the brain or in the general nervous system, and say ‘beyond this there is volition and intelligence, but up to this there is none.’”[131]

It has already been pointed out (Lecture V) that, in man, complicated actions which have been volitionally and perhaps laboriously acquired may be afterwards involuntarily and unconsciously performed.[132] In other words, after intelligent actions have been acquired by conscious processes, they may be performed by subconscious processes for which there is no conscious awareness and probably these may be either coconscious or entirely unconscious. There is no sharp dividing line between the activities of the unconscious, coconscious, and conscious.

When we descend in the scale of animal life to the insects (bees, ants, etc.,) we observe motor activity of a highly complex character of a kind that is termed intelligent, but we are forced to conclude, from various considerations, that the elements of consciousness have dwindled away to what can be nothing more than mere sensibility. In other words consciousness is reduced to its lowest terms, but behavior and the neural processes are maintained at a high level of complexity. Accordingly there is a disproportion between the complexity of the motor behavior and the inferred simplicity of consciousness, for in the higher animals the former would be correlated with complex psychological processes. If this be so, the motor activities must be determined by processes which are mostly unconscious.

In still lower forms of life the motor activities can be referred to simple tropisms, and thus necessarily are wholly unconscious.

Between the most complex unconscious physiological processes performed by the nervous system and the simpler cerebral processes accompanied by consciousness there is not as wide a step as might seem when superficially viewed. The physiological process may, as we have seen, manifest itself in acts of quite as intelligent a character as those exhibited by the conscious process, and indeed more so; for the conscious act may be little more than a limited reflex. On the other hand a psychological process may be so elementary that it contains nothing of awareness of self, of intelligence, or of volition in the true sense—nothing more, perhaps, than an elementary sensation without even perception. But it may be said that the presence of the most rudimentary state of consciousness makes all the difference and renders the gulf between the two impassable.

We are not called upon to discuss that question here. It is one which involves the ultimate nature of physical processes. A distinction should be made between psychological and psychical, these not being coextensive and always interchangeable terms. Psychological pertains to the empirical data of consciousness, (thoughts, ideas, sensations, etc.) while psychical pertains to the inner or ultimate nature of these data. Though the data as given in consciousness are psychical, that which is psychical may not be solely manifested as psychological phenomena. It may be manifested as physical phenomena and perhaps be identified with the energy of the universe. Hence the doctrine of panpsychism. And so it may be that in its ultimate analysis an unconscious process is psychical (monism) although not psychological and not manifesting itself as a datum of consciousness. Certain it is that, _objectively_ viewed, there is nothing to distinguish physiological from psychological intelligence. If the extraordinary instinctive habits exhibited by insects, such as bees and ants and by still lower forms of animal life, can rightly be interpreted as, in large part at least, manifestations of physiological processes, as is quite possible, the distinction between the conscious and the unconscious in respect to intelligence and adaptability to environment would be reduced to one only of degree. That some of the lowest forms of life are endowed with consciousness, in any sense in which the word has psychological meaning, seems incredible, though they manifest instinctive intelligence of no mean order. The fact probably is, as I have just intimated, that those processes we call physiological and those we call psychological are in their inner nature identical, and the former are quite capable of functioning, incredible as it may seem, in a fashion that we are accustomed to believe can only be the attribute of conscious intelligence. This does not mean, of course, that the physiological intelligence can reach the same degree of perfection as that reached by conscious intelligence, though conversely, the latter may be of a lower order than physiological intelligence.[133] From this point of view we are logically entitled to regard physiological processes, even of the lower nervous centers and even though they are not acquired but due to congenital structural and functional arrangement, as phases of the unconscious.

=Psycho-physical parallelism and monism.=—According to the doctrine of psycho-physical parallelism every mental process is correlated with (accompanied by) a brain process. As brain processes thus viewed are “unconscious” (in the sense of not having the attribute of consciousness) we may express this in other terms and say: every “conscious” process is accompanied by an “unconscious” process. I have no intention of entering here into the question of the validity of the doctrine of psycho-physical parallelism. I wish merely to point out that if parallelism is a true formulation of the mind-brain problem, as I have just stated it, the converse ought to hold true, namely, that every brain process of a certain kind involving intelligence ought to be correlated with consciousness. But if some subconscious processes manifesting what is equivalent to thought, reasoning, judgment, imagination, volition, etc., are unconscious—as seems likely if not probable—then this converse does not hold true. This has some bearing on the validity of the doctrine; for if physical processes can perform substantially the same function as conscious intelligence it is difficult to reconcile this fact with what I may call naïve psycho-physical parallelism.