The Sleep Instinct

Ray Meddis

• Publisher: Routledge
• Year: 2017
• ISBN:
  9781315312873
• Edition: 1
• Topic: Psychologie
• Subtopic: Psychologie clinique

Most of us believe that we sleep in order to rest our tired bodies and minds. Originally published in 1977, this centuries-old common-sense view is challenged by Ray Meddis, who describes and argues for a controversial new theory of the nature and function of sleep. The theory seeks to replace the old view with the idea that sleep may no longer serve any important function in modern man. Whereas the sleep instinct helps animals to survive by driving them to hide away for as long as possible each day, this is no longer a valuable asset in civilised surroundings. Nevertheless, as the author explains, we still feel driven by a primeval urge beyond conscious control to crawl away every evening to the security of our beds to wait out the dangerous hours of darkness which were such a threat to our ancestors. Contrary to contemporary wisdom, he also argues that dreaming is a primitive and particularly valueless kind of sleep – a crude a dangerous heritage from our reptilian ancestors which is kept to a bare minimum in most adult warm-blooded creatures.

Ray Meddis writes in a non-technical style and succeeds admirably in making the science of sleep and intensive research studies on sleep accessible and even exciting for the general reader as well as for the scientist. He shows that not everyone is bound by a felt need for sleep; in fact, some human beings discussed at length in the book thrive on less than two hours sleep a night without any ill effects. The implications of the research described are little short of sensational; in particular, Dr Meddis believes that it is well within the bounds of possibility that future research will show us how changes can be brought about in normal people to free them from the bondage of their sleep instincts. This new perspective also leads directly into a radical reappraisal of the nature of insomnia and new possibilities for treatment.

1 The joy of sleep

Like a great river flowing through a city, the sleep instinct flows gently but powerfully through our lives. While we can do nothing to stem its flow, we can and do come to terms with this natural force by sacrificing to it one whole third of our life. Indeed our sacrifice is often an enthusiastic one and sleep is rated by many as one of the greatest pleasures of life. They look forward to bedtime and savour the hours spent in bed until they reluctantly get up in the morning. Not everyone takes this view, of course. Many yield daily to the pressures of sleep without giving it a second thought until something goes wrong, like having difficulty in falling asleep. Like many pleasures, sleep can be easily taken for granted.

It may seem strange to talk about sleep as a source of pleasure rather than simply as a response to a felt need but if you doubt my proposition that people look to sleep as a source of pleasure as much as they look to good food, good company, wine, women and song, then try the following experiment. Ask yourself how you would respond to an (imaginary) new pill which would banish forever the need to sleep. I stress that this pill would cause you never again to feel drowsy, never again to nod off, but even so you would experience no ill-effects from the lack of sleep. Be quite clear, however, that once you have taken the pill you will never ever again fall asleep nor experience the desire to do so.

At first, you will probably be intrigued by the prospect of an extra eight hours of wakefulness which could easily be put to good use. You may enthuse about no more bed-making, no more wasting time getting ready for bed and later getting dressed again and no more early morning blues while shaking off tiredness before getting up. Perhaps you may think of taking another job or using those extra hours to write a novel or study for more qualifications.

But then you will wonder whether you really want to be active for twenty-four hours a day. It’s nice to put your feet up in the evening, even to lie down in a soft warm bed. Bed is a convenient place for love-making and how sweet it often is to fall gently and happily asleep afterwards. After a long day with difficulties on all sides it is pleasant to switch off and forget, to relax and take it easy, to discard all responsibilities till tomorrow.

In the end I shall find few takers of this non-sleep pill. Admittedly sleep is a nuisance but with careful management it does not interfere too much with a full and happy life. On the other hand sleep is too much of a joy to be separated from for ever. The same is true of sex which can also be a terrible time waster and source of limitless anguish. Yet, if we offered a single pill which would remove sexual desire for ever how many takers would we find? Sex like sleep is a potential source of pleasure which few wish to see taken away whatever difficulties its presence may otherwise cause.

Whereas the pleasures of sexual gratification are readily identified and analysed the matter is nowhere nearly as simple in the case of sleep. How can we say that we enjoy sleep when we are in fact unconscious at the time, apparently unaware of anything? Certainly people do not smile often during sleep and in the morning they rarely recall much of their experience. At first sight it looks to be a proper paradox.

It only remains a paradox if we insist on thinking of sleep as the same thing as being asleep. Usually when people say that they enjoy their sleep they are talking about more than simple unconsciousness. Sleep refers to the whole ritual of going to bed, slipping between the inviting covers, relaxing with closed eyes, drifting off to sleep and even the joy of waking at six in the morning to the discovery that you have another whole hour before needing to get up. The pleasures of sleep are not those of unconsciousness but the appreciation of being free to go to bed, free to drift off to sleep and, if we wake during the night, free to fall asleep again.

The parallel between sleep and sexual gratification extends beyond the potential for pleasure to the possibility of pain when either urge is frustrated. Here lie the miseries of insomnia and prolonged sleep deprivation. When we go to bed drowsy and hopeful, it is painful, and for some agonising, not to be able to fall asleep. During the night it can be intensely irritating if we wake up and find that we cannot get back to sleep. If this pattern continues night after night, the frustration and irritation can build up to depression, general misery or hyper-irritability even though (as in sexual frustration) there is no direct damage to health.

Another painful feature of sleep is the nasty business of getting up in the morning. Some lucky people do not experience thickheaded, irritable reluctance but they are in the minority. The man who discovers a marketable potion which causes us to wake up cheerfully will also have discovered a fortune. It has always seemed strange to me that the nausea we feel on waking after eight hours sleep is so similar to the nausea of prolonged sleep deprivation. Perhaps they are similar because in both cases we are highly motivated to go back to sleep.

Sleep as a motive

The desire to sleep is a motive which can be just as strong as the desire to eat or drink, even though psychologists rarely include it in their list of drives. A motive can be weak at some times and strong at other times; sometimes we are hungry, sometimes we are not. At any given time there is a competition among motives and it is the strongest one which gains control of our behaviour. In the evening when our desire to sleep is low and our desire to watch television is high, we watch television. Later our desire to sleep becomes more intense. At some point it becomes greater than our interest in the television and then we get up and go to bed.

Motives reflect the brain’s ability to control our behaviour by changing our priorities. In the case of hunger it is fairly clear how this works. When our food reserves fall low the brain detects this and makes a number of internal adjustments so that food becomes more attractive. If our hunger is not competing with some other more pressing need then we engage in learned sequences of activities which will bring us into contact with food. After we have eaten a certain amount the brain will adjust our priorities so that the food becomes less attractive and we will be tempted to get up from the table and set about some other more attractive project.

We shall need to consider how the sleep motive works in particular but first we should see how the satisfaction of a motive is linked with pleasure and pain. It is tempting to think that the pleasure associated with hunger comes with a full belly but this is too simple an analysis. Consider a hungry man driving through a fog to a restaurant where he knows that he can eat well. He experiences pleasure at a number of points, for example when he first sees the restaurant through the fog, when he gets into the dining-room and discovers that he is not too late for dinner, when the food arrives at the table, when he tastes the first delicious mouthful and finally when he experiences that warm glow of relaxed satisfaction at the end of the meal. Pleasure, it seems, is experienced at each of the signposts en route to his ultimate goal.

Alternatively pain may be experienced whenever he meets a signpost which indicates delay or frustration of his intentions, when he discovers that he is too late for dinner, when he notices that the waiters are serving other customers before him, when the food he tastes is obviously undercooked and when at the end of the meal he finds that he has not had enough. Pleasure and pain are the two guides which keep us on the narrow pathway to consummation. Pleasure encourages us when we are progressing well. Pain or displeasure discourages us when we stray from the quickest route to final satisfaction.

This analysis helps us understand why the pleasure we associate with sleep need not be experienced while we are actually unconscious. Instead it occurs at the various landmarks on the road to sleep. For some reason the brain decides in the late evening that being unconscious is an important goal. In order to achieve that goal it adjusts our priorities and creates a sleep motive which will make sleep-related achievements more pleasurable and other achievements less so. At this time it becomes pleasant for us to lie down, sweet to close our eyes and delicious to drift off. After that it does not matter. The goal of the sleep motive has been achieved, unless, of course, we wake up during the night and then it becomes pleasant to fall asleep again.

The sleep control mechanism

One of the brain’s many jobs is to assign priorities, to decide which problems will be tackled first. Sometimes it is fairly obvious how these decisions are made. The sight of a pretty girl has the effect of intensifying the courting urge, often at the expense of our desire to drive carefully. An empty belly gives food-seeking priority over studying. What, then, causes the brain to assign a high priority to falling asleep?

It is tempting to assume that the desire to sleep arises from the fatigue associated with prolonged waking activity. In other words the brain knows when it has had a hard day and needs a good rest. This is certainly a most popular belief but for two good reasons we should be suspicious of so simple an answer. First, no one has succeeded in showing satisfactorily that physical or mental effort is related to a need for sleep,¹ and second, observation of people who fly across time zones on long journeys has shown that the brain decides when to be sleepy on the basis of body-time, i.e. the time it thinks it is.

Because we feel tired at bed-time it is most natural to feel that we sleep because we are tired. The point seems so obvious that few have ever sought to question it. Nevertheless we must ask, ‘tired of what?’. It is true that people feel tired at the end of a hard day of manual work but it is also true that office workers feel equally tired when bed-time comes. Even invalids, confined to beds or wheelchairs, become tired as the evening wears on. Moreover, the manual worker will still feel tired even after a relaxing evening in front of the television or reading a book which we might reasonably expect to have a refreshing effect. There is no proven connection between physical exertion and the need for sleep. People want to sleep, however little exercise they have had.

Perhaps the desire for sleep is related to mental fatigue. Once again we shall find that there is little proven association. If anything, sleep comes more slowly to people who have had an intellectually challenging day, possibly because their minds are still full of thoughts when they eventually retire. Ironically a quick way of sending someone to sleep is to put him into a boring situation where the intellectual stimulation is minimal.

There is no good reason to believe that our sleep motive is aroused so that the brain can have a rest. Many people have suggested that during sleep the brain clears away waste products which have accumulated during wakefulness, or manufactures new chemicals which will be needed during the next day. So far this is still little more than biochemical fantasy supported not by evidence but by the preconceptions of scientists who have been educated to believe that sleep is necessary for some kind of physiological repair process to take place. So far, everything we have learnjt about the brain indicates that it could continue indefinitely, like the heart, without any pause for refuelling. Studies of nerve cell activity during sleep show that individual cells can be equally active during both sleep and waking.

Observation of long-distance travellers suggest that the desire for sleep is triggered more powerfully by the time of day the brain thinks it is, rather than by the length of time since they last got out of bed. For example, an American from New York visiting England on a business trip may have to leave his hotel bed at 7 a.m. every morning in order to keep to his appointments schedule. If he normally retires at 12 midnight at home in the USA, he may attempt to do the same in England but, during the first week at least, he will discover that he is not really sleepy until 5 a.m., i.e. midnight New York time. Because he has to rise soon after, he will be living on very short sleep rations indeed. Neverthless he will typically find during these first few days that when midnight comes he is wide awake and not yet ready for bed.

These considerations suggest that on a normal day the brain promotes the sleep motive to a high priority at a certain time, irrespective of what has happened during that day. At this time, activities preparatory to sleep are made to seem especially pleasant. If for some reason we do not yield to the lure of bed, then the priority increases gradually over the succeeding hours. It is this gradual increase after bed-time which creates the illusion that the critical factor, which triggers the sleep motive, is the number of hours of preceding wakefulness. Under normal circumstances however, the sleep-control mechanism is guided by the time of day (as judged by the brain) when choosing to create the predisposition to sleep.

Sleep as an instinct

Man is not the only animal in creation to spend many hours each day in a state of semi-conscious immobility. Far from it; sleep appears to be the rule rather than the exception in the animal kingdom. It is, in fact, so common that many authors have been tempted to think of sleeping as instinctive behaviour. Roughly speaking, an instinct is an innate biological force which predisposes the organism to act in a certain way. Instinctive behaviour is automatic and involuntary. Moreover the behaviour pattern is very similar in all members of the same species. This certainly appears to be true for man. In any large city, between the hours of 11 p.m. and 1 a.m., there are millions of people all rubbing their eyes and yawning, all saying how tired they feel, all making their way to bed, making themselves comfortable, closing their eyes and lying still. The action patterns are automatic, stereotyped and largely involuntary.

Instinct theorists usually divide instinctive actions into two phases. The first phase is preparatory and technically named ‘appetitive’. In the case of the sex instinct, the appetitive phase is the courtship period. The second phase involves the actions which constitute the goal of the instinct; this is called the consummatory act. Copulation and ejaculation are consummatory acts. As for the sleep instinct, the appetitive or preparatory phase includes all actions which contribute to getting us comfortably settled into bed, whereas the consummatory act is the business of falling asleep.

There is still considerable controversy attached to the idea of instincts. Many believe that the concept is not at all helpful in understanding the control of behaviour and we shall do well to avoid this particularly tangled argument. Let us note, however, that authors often use the term instinct to emphasise that the major components of the behaviour pattern are largely genetically pre-programmed. This in turn suggests that the behaviour is vital to the survival of the species. Individuals are therefore born with the capacity and the predispostion to act in this particular way when the circumstances are appropriate. Some learning is often required but very little is left to chance. As a result, almost all adult male animals raised in natural surroundings will copulate effectively given the right circumstances. Similarly, they will all make their way to the appropriate sleeping site and fall asleep at the right time of day.

If sleep is an instinct, we might speculate that it plays a vital role in the survival of many species. It is certainly largely unlearned although it does slowly come to be associated with a large number of learned habits. Whereas sexual behaviour is typically stimulated by the sight or smell of a receptive partner, sleep is not obviously affected by external influences. Instead the sleep instinct is triggered by an internal clock which registers the time of day. Once triggered there follows a fairly regular sequence of actions which, with a little luck, is soon followed by the consummation of sleep.

The idea that sleep is an instinct, which is stirred everyday at a particular time, is a radical departure from the traditional view that sleep is a passive response to the accumulated fatigue of the day. It reflects a growing tendency among scientists to reject the idea that sleep is a passive state. Increasingly they see sleep as a state which is actively switched on, and later switched off, by some central control mechanism, like the urge to hibernate which many animals experience when the days grow short and cold. Long nights and inclement weather do not directly make these animals sleepy. Instead they trigger some central mechanism which sets in motion all of the action sequences which prepare for the long period of inactivity. Only when this appetitive phase of the hibernation instinct is complete, can the consummatory act, of falling into the long sleep, take place.

Drowsiness

The view that sleep is actively controlled by the central nervous system has one very surprising but important implication. This is that our feelings of sleepiness which we experience in the late evening are artificially created at that time by the brain and that they need bear no obvious relationship to the activities of the preceding day. It is as if the brain has decided that it is time to go to bed.

It is a pity that the recent intensive sleep-research effort has almost totally ignored the magical phenomenon of drowsiness. It appears quite spontaneously and grows insidiously from an imperceptible beginning to become a powerful force in a matter of hours. Like most feelings it defies verbal analysis but you may care to reflect upon its nature when drowsiness comes over you tonight. The physical components of this feeling are particularly difficult to specify but a mild itching of the eyes which causes rubbing is obviously common. At the same time a conscious effort is required to keep them from closing. Many people feel a kind of muscular itch which makes them want to stretch. This is accompanied by muscular reluctance which increases our awareness of effort when we begin to do things. Rubbing the eyes and stretching the limbs brings only temporary relief and the symptoms return quickly. The conviction grows slowly but certainly that the only solution is to close the eyes, lie down and rest.

The most striking aspect of drowsiness is the way it changes your attitude to what you are doing. Whether you are reading a book, watching television, enjoying a conversation, filling in a crossword or whatever, your interest gradually slackens. You are unlikely to fall asleep on the job but your ability to maintain concentration and your inclination to continue, gradually weaken. At the same time the idea of lying down in a warm bed becomes more and more attractive. How quickly the change takes place depends upon the interest of the task in hand. Drowsiness quickly takes over if you are reading a boring book but it can be held at bay for hours if you are having a good time at a party. Sooner or later, however, we yield to the attractions of the supine posture and the freedom to close our eyes. Sooner or later we end up in bed.

Drowsiness is the chief agent of the sleep-control system. It is used not only to get us to bed but also to help us fall asleep. If we wake up during the night, drowsiness is still there to help us gently back into unconsciousness. It helps us fall asleep by causing the mind to wander aimlessly, to drift about, in such a way that we do not notice our translation from the world of the waking into the underworld of the sleeping. Normally the brain...

Table of contents

• Cover Page
• Half Title
• Title Page
• Copyright Page
• Contents
• Preface
• 1 The joy of sleep
• 2 The origins of sleep
• 3 Very short sleepers
• 4 Sleep deprivation
• 5 Dreaming sleep
• 6 The origin of dreaming sleep
• 7 Insomnia
• 8 Review
• Notes and references
• Index