The human clinical material is limited, and electro-encephalography is a recent invention; thus most of the evidence is provided by experimentation on animals. They are basically of two kinds: electrical or chemical excitation of the brain, and surgical elimination of certain areas of it. Let me quote MacLean again:
From animal experimentation on limbic epilepsy (induced by electrical stimulation) it has become evident that seizure-discharges induced in the limbic lobe tend in their spread to be confined to the limbic system. Seldom do the discharges, analogous to stampeding bulls, burst out of this corral and jump the fence into the neo-mammalian brain. Such experiments provide the most striking evidence available of a dichotomy of function (or what has been called a 'schizophysiology' of the limbic and neocortical systems). Patients with smouldering limbic epilepsy may manifest all the symptoms of schizophrenia; the schizophysiology in question is possibly relevant to the pathogenesis of this disease. . . . From the standpoint of the patient lying on the couch, the schizophysiology under consideration is significant because it indicates that the lower mammalian brain is able to some degree to function independently, to make up its own mind. The primitive, crude screen provided by the limbic cortex might be imagined as portraying a confused picture o[ the inside world and the outside world. This may partly account for the manifest confusion that has been described in psychosomatic conditions -- the confusion, for example, in which food or other edibles serve as representations of something in the external world that is desired to be assimilated into the self or mastered and destroyed like a prey or enemy.* One finds descriptions of the patient who eats presumably because of the need for love, because of anxiety or nervousness, or because of the need to chew up or get rid of what arouses his anger and hate. [27] * The relevance of this to the phenomena discussed on pp 228 f is obvious.
More recent methods of experimentation with implanted electrodes which permit low-voltage stimulation of precisely defined points of the monkey's brain, produced even more striking results. Stimulation of certain loci in the limbic system caused penile erection or ejaculation in males; stimulation of other points caused feeding reactions -- chewing and salivation; yet other areas elicited exploratory, aggressive-defensive or fearful behaviour. (It should be pointed out that these experiments are painless, and that monkeys with implanted electrodes in the so-called 'pleasure centres' quickly and willingly learn to stimulate themselves by pressing a lever which activates the current.) However, excitement of one kind readily spills over to adjacent points which arouse emotions of another kind. Thus oral activity --- chewing, srtiffing, salivation -- may combine with aggression; aggressive display with sex; sex with oral activity. Feeding often produces erection in babies and dogs; and some other aspects of doggy behaviour also fall far below Victorian standards.
'Schizophysiology'
Here again, the contrast between old and new cortex provides an unexpected clue, and an added dimension to the psychoanalytical approach. On the new TV screen (the sensory cortex) the body is represented in the well-known form of a little homunculus, shown in all textbooks, on which the mouth and the anal-genital region are placed correctly at opposite ends of the projection area. In the old, lower mammalian brain, however, 'nature apparently found it necessary to bend the limbic lobe upon itself in order to afford the olfactory sense close participation in both oral and anogenital functions'. [28]
This is a truly unexpected vindication of Freud's theory of infantile sexuality. It is at the same time a reminder that the survival of the lower mammalian brain in our heads is not metaphor but fact. In the sexual, as in all other contexts, maturation seems to mean a transition from the domination of the old brain towards the domination of the new. But quite apart from emotional upsets and pathological conditions, the transition even in the normal person can never be complete. The schizophysiology is built into our species.
In surgical ablation experiments, the effects are more drastic. After excision of certain parts of the limbic lobe, monkeys of previously savage temperament seem to lose the instinctive reactions necessary for survival. They become docile, show neither fear nor anger, do not fight back when provoked, do not learn to avoid painful situations. They also lose their instinctive feeding habits: a monkey which normally lives on fruit will now eat raw meat or fish, and show a compulsive tendency to put every object into its mouth: nails, faeces, burning matches. Lastly, the sexual and maternal instincts also go haywire: male cats will try to copulate with chickens, and mother rats will let their litter die. [29]
However, the old brain is not merely concerned with affect; it also perceives, remembers and 'thinks' in its own, quasi-independent ways. In primitive animals, the limbic system is the highest integrative centre for the drives of hunger, sex, fight and flight; and the anatomical and physiological evidence indicates that it continues to serve these functions in higher animals, including man. It occupies, as already mentioned, a strategically central position for correlating internal sensations with perceptions from the outside world, and for initiating appropriate action according to its own lights. Though dominated by instinct, it is clearly capable of learning simple lessons: a monkey will taste a burning match only once, if its limbic system is intact; if it is damaged, it will burn its mouth over and again. 'One can hardly imagine a more useless brain than one that sat around by itself all day generating nothing but emotions and not participating in cognitive, memory and other functions.' [30] But it functions all the same in a phylogenetically old-fashioned way -- in a way which psychiatrists call infantile or primitive.
On the basis of the foregoing observations one might infer that [the old cortex] could hardly deal with information in more than a crude way, and was possibly too primitive a brain to analyse language. Yet it might have the capacity to participate in a non-verbal type of symbolism. This would have significant implications as far as symbolism affects the emotional life of the individual. One might imagine, for example, that though the visceral brain could never aspire to conceive of the colour red in terms of a three-letter word or as a specific wave-length of light, it could associate the colour symbolically with such diverse things as blood, fainting, fighting, flowers, etc. -- correlations leading to phobias, obsessive-compulsive behaviour, etc. Lacking the help and control of the neocortex, its impressions would be discharged without modification into the hypothalamus and lower centres of affective behaviour. Considered in the light of Freudian psychology, the old brain would have many of the attributes of the unconscious id. One might argue, however, that the visceral brain is not at all unconscious (possibly not even in certain stages of sleep), but rather eludes the grasp of the intellect because its animalistic and primitive structure makes it impossible to communicate in verbal terms. Perhaps it were more proper to say, therefore, it was an animalistic and illiterate brain. (MacLean [31]; italics in the original).
A Taste of the Sun
Our emotions are indeed notoriously inarticulate, incommunicable in verbal terms. The novelist's main difficulty is to describe what his characters feel -- as distinct from what they think or do. We can describe intellectual processes in the most intricate detail, but have only the crudest vocabulary even for the vital sensations of bodily pain -- as both physician and patient know to their sorrow. Suffering is 'dumb'. Love, anger, guilt, mourning, joy, anxiety command a vast rainbow spectrum of emotions of varied colour and intensity which we are unable to convey verbally, except for trite clichés -- 'broken hearts' and 'pangs of despair'; or else by the indirect method of invoking visual imagery and the hypnotic effect of rhythm and euphony, which 'lull the mind into a waking trace'.
Poetry could thus be said to achieve a synthesis between the sophisticated reasoning of the neocortex and the more primitive emotional ways of the old brain. This reculer pour mieux sauter, draw-back-to-leap process, which seems to underlie all creative achievement, may reflect a temporary regression from over-concrete, neocortical thinking to more fluid and 'instinctive' modes of limbic thinki
ng -- a 'regression to the id in the service of the ego'. We also remember that sometimes 'we have to get away from speech to think clearly' -- and speech is a monopoly of the new cortex. In a similar way, other phenomena discussed in the chapters on creativity and on memory can be interpreted in terms of hierarchic levels in the evolution of the brain. Thus, for instance, the distinction we have made between abstractive memory, on the one hand, and the emotionally significant 'picture-strip' on the other (Chapter VI), seems to reflect the characteristic distinction between the new and ancient brain.*
* Cf. also Kluever's three levels of visual memory [31a] (p. 90).
The consequences of the innate 'schizophysiology' of man thus range from the creative to the pathological. If the former is a reculer pour mieux sauter, the latter is a reculer sans sauter. Its forms vary from what we regard as more or less normal behaviour, where unconscious emotional bias distorts reasoning only to a moderate extent, in socially approved or tolerated ways, through the open or smouldering conflicts of neurosis, to psychosis and psychosomatic disease. In extreme cases, the distinction between the outer and inner world can become blurred -- not only by hallucinations, but also in other ways; the patient seems to regress to the magic universe of the primitive: 'The impression is gained clinically that [these] patients . . . show an exaggerated tendency to regard the external world as though it were part of themselves. In other words, internal feelings are blended with what is seen, heard or otherwise sensed in such a way that the outside world is experienced as though it were inside. In this respect there is a resemblance to children and primitive peoples.' [32] An example of such confusion is the remark of a girl suffering from epilepsy about her first seizure -- which occurred when, as a child, she walked into the bright sunlight: 'I had a funny taste in my mouth of the sun.' A poet might have written that line; but unlike the poor child, he would have been aware of his own confusion.
'Knowing with one's Viscera'
We all can sometimes feel the taste of the sun in the mouth; but our major confusions arise, not from such visceral interference with our perceptions, but with our convictions and beliefs. Irrational beliefs are anchored in emotion; they are felt to be true. Believing has been described as 'knowing with one's viscera'. More correctly we should say that it is a type of knowing which is dominated by the influence of the inarticulate old brain, even if it is formulated in articulate verbal terms. At this point, these neurophysiological considerations merge with the psychological phenomena discussed in the previous chapter. The schizophysiology of the brain provides a clue to the delusional streak in the history of man.
A closed system, as defined in the previous chapter, is a cognitive matrix with a distorted logic, the distortion being caused by some central axiom, postulate, or dogma, to which the subject is emotionally committed, and from which the rules of processing the data are derived. Cognitive systems are, of course, not exclusive products of the reptilian or paleo-mammalian or neo-mammalian brain, but of their combined efforts. The amount of distortion varies according to which level dominates, and to what extent. Without some contribution from the ancient levels concerned with internal, bodily sensations, the experience of our own reality would probably be absent -- we should be like 'disembodied spirits' (MacLean [33]). Without the neocortex, we should be at the mercy of affect, and our thinking would be like the monkey's or infant's. But detached, rational thought is a new and fragile acquisition; it is affected by the slightest irritation of the old brain which, once aroused, tends to dominate the scene.
However, we know that in between the 'disembodied spirit' of pure abstract reasoning, and the passionate neighings in the old cortex, there is a series of intermediary levels. As already said (pp. 180 f), it would be a gross oversimplification to distinguish only two types of mentation, such as Freud's 'primary' and 'secondary' process, the first governed by the pleasure principle, the second by the reality principle. In between these two, we have to interpolate several methods of cognition, as we find them in primitive societies at various stages of development, in children at various ages, and in adults in various states of consciousness -- such as dreaming, day-dreaming, hallucinating, etc. Each of these systems of thought has its own canon, its particular 'rules of the game', which reflect -- in a manner we are at a loss to explain -- the complex interactions of various levels and structures in the brain. The old and new levels must interact all the time -- -even if their co-ordination is inadequate, and deficient in the controls which lend stability to a well-balanced hierarchy.
One of the consequences of this is that verbal symbols become associated with emotive values and visceral reactions -- as the psychogalvanic lie-detector so dramatically shows. And that applies, of course, not only to single words or single ideas; complex doctrines, theories, ideologies are apt to acquire a similar emotional saturation -- not to mention fetishes, leader-figures and Causes. Unfortunately, we cannot apply a lie-detector to measure the irrationality of our belief-systems, or the visceral component in our rationalisations. The true believer moves in a vicious circle inside his closed system: he can prove to his satisfaction everything that he believes, and he believes everything he can prove.
Janus Revisited
MacLean distinguishes two basic motivational drives, each giving rise to its appropriate types of emotion: self-preservation and preservation of the species. His experimental work on monkeys led him to a tentative localisation of the first in the lower, of the second in the upper half of the limbic system. The emotions derived from the self-preserving drives are the classic trinity of hunger, rage and fear. They depend on the sympathetic division of the autonomic nervous system and on the galvanising effect of adrenal hormones released into the bloodstream. If we include the aggressive and oral components of sexual behaviour into this group (and we have seen how electric stimulation of one of these responses spills over into another), we get a fairly complete inventory of what we have called the self-assertive tendencies.
The other of MacLean's basic drives, preservation of the species, is a less clear-cut category. He includes in it the care of the young, the grooming habits and other forms of friendly social behaviour in monkeys; but he seems to regard them in the Freudian tradition, as derivatives from the sexual drive:
Concern for the welfare and preservation of the species is based on sexuality, and in man it reflects itself in a multiplicity of ways. It is a concern that leads to courtship and the eventual rearing of the family. It is a concern that permeates our songs, our poetry, our novels, art, theatre, architecture. It is a concern that preoccupies us in planning for the higher education of our children. It is a concern that promotes the building of libraries, institutes of research, and hospitals. It is a concern that inspired medical research to prevent suffering and dying of patients. . . . It is a concern that makes us think in terms of rockets, travel in outer space, and the possibility of immortal life in some other world. [34]
By the time we have travelled from the first sentence of this quotation to the last, the connection with sexuality has become more and more tenuous -- unless we subscribe to the doctrine that all social, artistic and scientific activities are sublimations or substitutions for sexuality. It is equally difficult to see how the 'magnetic force', as Konrad Lorenz has called it, which holds a herd or a shoal of ocean fish together -- an attraction which seems to increase in geometrical proportion with the size of the shoal and to depend on no other factors [35] -- could be based on sexuality. The same consideration applies to the division of labour in the beehive, with its vast proportion of sexless workers. Even though the most powerful of drives, sexuality is not the only, and perhaps not even the primary, bond which holds animal and human societies together, and which ensures the preservation and welfare of the species -- including the spiritual and artistic welfare of our own. It seems therefore more appropriate to include the sexual instinct, together with the other forces of social cohesion, in the more general category of our 'integrative tendencies'. Sex, as we have s
een, is a relative late-comer on the evolutionary stage; whereas the polarity of self-assertive versus integrative tendencies is inherent in all hicrarchic order, and present on every level of living organisms and social organisations.
In the animal kingdom, of course, MacLean's term 'preservation and welfare of the species' (as distinct from self-preservation) covers practically all manifestations of what we call the integrative tendencies; and if MacLean is correct in localising them in the upper half of the limbic system, and the drives of self-preservation in the lower half, we cannot ask for a better confirmation of the postulated polarity.
Thus as long as we confine the discussion to monkeys, the question of terminology is reduced to a semantic quibble. But when we come to man, the integrative tendency may assume a variety of forms, including the self-transcending emotions which enter into religious and artistic experience, but have little bearing on preservation of the species. They too must have their neurophysiological correlates, but here the subject becomes rather technical, and the general reader may safely skip the next two paragraphs.
We have seen that a close correlation exists between the aggressive-defensive emotions and the sympathetic division of the autonomic nervous system. It would be tempting to assume a symmetrical correlation between the self-transcending emotions and the other division of the autonomic system -- the parasympathetic. There is some evidence in favour of this view, although it is not conclusive. In general (but there are, as we shall presently see, important exceptions) the action of the two divisions is mutually antagonistic: they equilibrate each other. The sympathetic division prepares the animal for emergency reactions under the stress of hunger, pain, rage and fear. It accelerates the pulse, increases blood-pressure, provides added blood-sugar as a source of energy. The parasympathetic division does in almost every respect the opposite: it lowers blood-pressure, slows the heart, neutralises excesses of blood-sugar, facilitates digestion and the disposal of body wastes; activates the tear-glands -- it is generally calming and cathartic. Characteristically, laughter is a sympathetic, weeping a parasympathetic, discharge.