by Lyall Watson
Sheldon's "constitutional psychology" is based on some extensive surveys in the United States where there is a mixture of racial and physical types that have been more or less detached from their cultures, but it has never been accepted into the mainstream of personality psychology. Objections to it have been made largely on the grounds that it is not possible to decide from the evidence whether the influence of body shape on character is a direct physical one or an indirect social one. Many doubt that there is any cause and effect relationship at all, but very little work has been done in this area in the last thirty years and we are left with a concept that is both obscure and a little tantalizing.
Sexual stereotypes are as common as cultural and racial conventions. There is considerable evidence to show that some personality differences in men and women are produced solely by the roles forced on individuals by the society in which they live, but there are also purely biological bases for psychological sex differences. Males and females differ in every cell of their bodies. Only males have the small Y chromosome that produces masculine development. If it is absent, the development proceeds according to the female pattern. It is important to remember, however, that genes do not control behavior: they control chemical processes that in the end produce individuals that are wired up differently and will produce different responses to the same situation.
Females hear better than males; their discrimination and localization of sounds is superior at all ages. Males, on the other hand, see better. These sex differences are not learned; they are present right from the beginning. One psychologist who was trying to train fourteen-week-old infants to look at an object found that he was able to do so successfully only if he used sounds as reinforcement for the girls and lights for the boys. [291] Later in development, these differences become apparent in the fact that girls learn to talk earlier than boys. They articulate better, write and spell more fluently, and acquire a more extensive vocabulary than boys of the same age. The boys, on the other hand, excell in spatial ability. Their visual skills are manifest in activities such as aiming at a target, arranging objects in patterns, or having a good sense of direction. [100] The evolutionary advantages of these differences are obvious. The prolonged dependence of the human baby means that the female is tied to it for several years, and under these conditions she relies a great deal on the skills of communication. The male, being free to move around more easily and also having greater agility and strength, was destined to be the hunter, and good vision and a sense of direction clearly had advantages in this field.
During the course of human evolution, these biological and cultural factors have worked together to produce sexes that are substantially different. The little Y chromosome started a chain reaction that ends with two totally distinctive personality structures. The ethnologist Corinne Hutt summarizes the differences in this way: "The male is physically stronger but less resilient, he is more independent, adventurous and aggressive, he is more ambitious and competitive, he has greater spatial, numerical and mechanical ability, he is more likely to construe the world in terms of objects, ideas and theories. The female at the outset possesses those sensory capacities which facilitate interpersonal communication; physically and psychologically she matures more rapidly, her verbal skills are precocious and proficient, she is more nurturant, affiliative, more consistent, and is likely to construe the world in personal, moral and aesthetic terms." [125]
In rhesus monkeys the very young males threaten each other and indulge in rough-and-tumble play more often than females. The females tend to sit quietly, grooming each other, and to turn their heads away with a rigid body posture when approached. Harry Harlow at the University of Wisconsin found that the infant monkeys showed these sex-typical behavior patterns even when reared in isolation by a cloth-covered wire model instead of a mother. He concludes that "it is extremely difficult for us to believe that these differences are cultural, for we cannot imagine how our inanimate surrogate mothers could transmit culture to their infants." [106]
It seems clear that at all stages of development, the abilities and personalities of males and females differ due to biological determinants. Arguments about which patterns are better or worse, more or less advanced, are totally irrelevant and depend entirely on what is being measured and by whom. Only one thing is certain in any consideration of the sexes, and that is that they are different.
There is little doubt that personality and psychological differences have biological bases. They are determined partly by given genetic factors and partly by the measurable environmental factors to which the developing individual is exposed. The process of personality growth involves a selection of certain factors from the environment and the arrangement of these in a characteristic way. The manner in which it develops is similar to the way in which the unique structure of some solid crystallizes out of a solution in which it floats. A wide range of crystals can be formed from a solution as complex as seawater, but their nature is limited to the kinds of molecule available in that environment. Any change in the environment will be directly reflected in the matter produced there. Even when a personality is fully developed, it can be altered dramatically by a purely physical malfunction or by the administration of a chemical that interferes in some way with the physiological processes involved in maintaining that personality. Work on the personality differences that occur with aging shows that some of these, such as lowered confidence and increased cautiousness, are a direct result of physical inability; but there are more subtle age changes, such as increased introversion and lowered emotionality, which suggest that physiological aging is accompanied by a parallel process of psychological change. [47]
All this points to the conclusion that personality is very much grounded in the body and makes it difficult to believe anything of the unique character of an individual can stirvive the elimination of the body on which it depends -- but we have not yet examined all the evidence.
Dean W. R. Matthews has suggested a working definition of survival which seems to make biological sense. His hypothesis is "that the center of consciousness which was in existence before death does not cease to be in existence after death and that the experience of this center after death has the same kind of continuity with its experience before death as that of a man who sleeps for a while and wakes again." [178] This is a valuable idea because it introduces the question of continuity and reminds us that there are interruptions of continuity even in the lifetime of every body.
We have already decided that sleeping and dying have little in common, but it is worth remembering that when sensory stimuli acting on a body from outside are reduced to a minimum, we tend to fall asleep, and that when stimuli coming from within the body are reduced, this sleep tends to be dreamless. After clinical death, stimuli coming from the outside are reduced to a minimum. We can prove this by showing that the sense organs no longer send electrical signals about these stimuli to the brain. Internal stimuli are also progressively reduced until they cease altogether, so it would seem that consciousness must be even less active in death than it is in sleep. As far as we know, the center of consciousness is located in the cortex of the brain. Nathaniel Kleitman at the University of Chicago has surgically removed the cortex from dogs and found that when they recover from the operation, they spend most of their time in dreamless sleep, but they also wake occasionally to eat, drink, and excrete before going back to sleep. [149] Consciousness and wakefulness are not synonymous. It is possible to be awake without being conscious, and as dreams show, it is certainly possible to be conscious without being awake.
One of my problems, as a biologist faced with the thought of a disembodied personality, is that I find it difficult to imagine how this abstract entity could enjoy any kind of experience. Without sense organs, it would have to perceive things by clairvoyance; without limbs, it would be able to act on the environment only by psychokinesis; and without any structures for producing vocal, visual, or olfactory signals, it could communicate only by telepathy. No
ne of these things is biologically impossible, but they all differ so radically from our usual ways of dealing with the environment that any experiences after clinical death will probably be very different from those we enjoy during life and cannot on these grounds be considered as continuous with everyday sensations. The chances are that if a personality does continue to exist, its character will be so different from the living one that it might be impossible for us to recognize it. The only biological comparison available to us at the moment is the kind of experience we know occurs in dreams.
Dreams include sensations of color, sound, texture, temperature, smell, taste, pain, and all the other experiences we appreciate through our sense organs in waking life. In dreams we run and jump and caress and kill with limbs that seem at the time to be as real as those we use during the day. We meet familiar people or total strangers and carry on involved and often highly intelligent conversations with them completely in our imaginations. It seems that we each have within us all the necessary mechanisms for producing elaborate, coherent, and sustained images without any of the external stimuli that form the basis of normal waking perception. In these dream situations we seem to express our usual daytime personalities. In fact, if the Freudian interpretation of dream content is correct, we do even more than that by allowing expression also of subconscious personality traits normally hidden during the day. So in the dream stream of consciousness, we have everything necessary to allow a personality to continue to enjoy internally coherent experiences without the need for additional external stimulation taking place simultaneously. This mechanism would in itself be sufficient to explain complete survival of the intact human personality following clinical death, if it could be shown to be independent of body physiology.
One of the oldest theories about dreams suggested that they were produced by the stimuli that the internal organs continue to send on to the brain even during sleep. Freud once tried eating salted anchovies late at night and reported that he dreamed repeatedly of drinking water. Dream laboratory experiments in which a humming tone is sounded or water sprayed onto a sleeper's face often coincide with reports that include an airplane or a waterfall, but there is no evidence to suggest that most dream images arise in this physiological way. [171] All dreaming is accompanied by an extraordinary internal frenzy. In 1952 rapid movement of the eyes was associated with the onset of dreaming and provided the first reliable indicator of the switch from orthodox sleep to the dream state, but it is by no means the only physical change that takes place. Pulse rate and breathing become erratic, blood pressure climbs above the normal waking levels, oxygen consumption is increased, the level of the hormones adrenaline and cortisone in the blood rises sharply, and the temperature of the brain soars to alarming levels. This hot brain is an indication of rapid conversion of energy and is a condition found in waking only at times of rage or crisis. Measurements made on single brain cells show that they change from the slow regular discharge of waking and ordinary sleeping to explosions of uncontrolled activity the moment a dream begins. [243] The evidence suggests that physical changes that can be measured during dream sleep are caused by the dream.
Five or six times every night each one of us goes through this bodily ferment. We seem to need to, because if dreaming is prevented, neuroses and undue excitement appear. William Dement and his team at Stanford University worked for some years with cats and found that after more than twenty days of dream deprivation, the animals became very restless and intense and showed all kinds of exaggerated behavior. [60] Purely by accident, one of these excitable cats was given a light electrical shock while being attached to a piece of recording apparatus. Normally this stimulus would have produced no marked response, but it threw this particular cat into convulsions. The dream~deprived brain is obviously highly excitable, and what usually happens when it is once again allowed to sleep without interruption is that it goes into a prolonged orgy of dreaming to make up the deficit. After its convulsion had passed, the Stanford cat slept, but the monitors showed that it spent no longer in dream sleep than any normal nondeprived cat. The electroconvulsive shock apparently supplied the release that its body normally received from dream sleep.
Following this dramatic discovery, Dement examined the sleep patterns of human patients before and after they received electroconvulsive therapy. [61] In every instance there was less dream sleep after the treatment than there had been before. The hurricane in the brain produced by electric shock seems to be directly comparable to the storm that rages during dreaming. The dream now begins to look like a form of therapy, a loosing of psychological controls and a way of discharging the waves of nervous excitement that build up in the body each day. It is tempting to compare its actions with the convulsions of epilepsy.
After a fit, most epileptics fall asleep. Many suffer all their seizures during sleep, but very rarely during the rapid eye movement stages. The frequency of the brain waves during an epileptic attack is similar to that seen in an actively dreaming brain, and the flicker of light that induces an artificial fit is identical to the frequency that appears at the onset of dreaming. It begins to look as though the epileptic might be someone who, for some reason or another, could also be dream-deprived. Both epileptic and dream states produce dramatic and necessary changes in the chemistry of the brain, but nobody has yet been able to pinpoint the source of either stimulus with any accuracy. In the fits of grand mal and in the fever of lunatic visions in a dream, the systems of the body are pushed dangerously close to the limits of endurance. There has to be a very good reason for us to expose ourselves to this kind of risk five times a day, every day.
We start dreaming very early. In the dark waters of the womb the faster voltage patterns of dreaming have already begun to break into the long slow waves of relaxation. After birth, a baby spends most of its time asleep and nearly all of this is paradoxical dream sleep. Orthodox sleep hardly occurs until the nervous system has acquired a certain amount of maturity. A newborn kitten spends half its time in the waking state, prowling around with its eyes still shut demanding to be fed, and half in dream sleep. [134] It goes directly from one state into the other without the intervening period of orthodox sleep that appears in all adults. By the end of the first month, the kitten's time is divided almost equally between waking, sleeping, and dreaming; thereafter the duration of wakefulness and orthodox sleep both increase, and as an adult a cat behaves like a man, dreaming about 20 per cent of its life away.
I do not hesitate to equate the rapid eye movement sleep in animals with dreaming. Pet owners have always believed that the sniffing, whining, flapping, sucking, and wagging that go on in some phases of sleep in cats or dogs were signs of dreaming. There is every reason to believe that this is true. It would seem to be impossible to ask an animal to tell us whether or not it dreams, but Charles Vaughan at the University of Pittsburgh has done just that. [280] Like most of the best discoveries, this one was accidental and occurred during an experiment designed to test the rhesus monkey's reaction to sensory deprivation. The monkeys were placed in a chair in a modified telephone booth and given an electric shock every time they did not press a bar very rapidly after an image appeared on the screen in front of them. A huge variety of slides were projected and the monkeys proved to be very reliable, pressing the bar without error as often as three thousand times an hour. Then Vaughan turned on a uniform waterfall sound, fitted the monkeys with opaque contact lenses, and shut the booth off completely from all outside stimulation. He hoped that in these monotonous conditions the monkeys would suffer, as humans do, from hallucinatiqns and that when they saw visions they would respond by pressing the bar. Unfortunately, the monkeys responded to the monotony exactly like humans -- and fell asleep. Then came the bonus discovery. As soon as the monkeys' eyes began making rapid darting movements in their sleep, they started pressing the bar. They were seeing things in their sleep and all of them continued for many minutes, breathing deeply, flaring their nostrils, making faces and noises as they pounde
d away at the bar. The same kind of experiment is now being repeated with rats, cats, and dogs, and work is under way to design systems with numbers of bars that have to be pressed for different objects, so that the animals can tell us what it is that they have been dreaming about.
Paradoxical sleep occurs only in warm-blooded vertebrates. Fish and reptiles certainly sleep, but always in the light orthodox way. On an evolutionary scale, dream sleep patterns first appear among birds. Only pigeons and chickens have so far been tested and both species produced very brief bursts of paradoxical sleep, lasting no longer than fifteen seconds at a time. [135] The dream state occupies less than 1 per cent of their lives, but when it does appear, it follows the usual mammalian pattern. Every mammal ever tested has proved to spend at least part of its sleep periods in the dream state. In this condition the muscles of the body are more relaxed than in orthodox sleep, so it is no surprise to discover that predators can afford to dream more often and more easily than their prey. Dream sleep is obviously concerned mainly with the brain, and it cannot be purely coincidental that it should also occur for longer periods in species such as cats, raccoons, monkeys, and men, which have higher levels of consciousness and intelligence than sheep or rabbits. It seems likely that dreams have a great deal to do with the development and the integration of consciousness.