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6 - TALES OF DIM EDEN
Very old are we men; Our dreams are tales Told in dim Eden...
WALTER DE LA MARE
“All That’s Past”
“Well, at any rate it’s a great comfort,” she said as she stepped
under the trees, “after being so hot to get into the-into the-into
what?” she went on, rather surprised at not being able to think of
the word. “I mean to get under the-under the-under this, you know!”
putting her hand on the trunk of the tree. “What does it call
itself, I wonder?”... And now, who am I? I will remember, if I
can! I’m determined to do it!” But being determined didn’t help her
much, and all she could say, after a great deal of puzzling, was “L,
I know it begins with L!“
LEWIS CARROLL
Alice Through the Looking Glass
Come not between the dragon and his wrath.
WM. SHAKESPEARE
King Lear
... At first
Senseless as beasts I gave men sense, possessed them of mind...
In the beginning, seeing, they saw amiss, and hearing, heard not,
but like phantoms huddled In dreams, the perplexed story of their
days Confounded.
AESCHYLUS
Prometheus Bound
PROMETHEUS is in a fit of righteous indignation. He has
introduced civilization to a befuddled and superstitious mankind,
and for his pains Zeus has chained him to a rock and set
a
vulture to pluck at his liver. In the passage following the above
quotation, Prometheus describes the principal gifts, other than
fire, that he has bestowed on mankind. They are, in order:
astronomy; mathematics; writing; the domestication of animals;
the invention of chariots, sailing ships and medicine; and the
discovery of divination by dreams and other methods.
The final
gift strikes the modern ear as odd. Along with the account in
Genesis of the exile from Eden, Prometheus Bound seems to be one of
the major works in Western literature that presents a viable
allegory of the evolution of man- although in this case
concentrating much more on the “evolver” than on the evolved.
“Prometheus” is Greek for “foresight,” that quality claimed to
reside in the frontal lobes of the neocortex; and foresight and
anxiety are both present in Aeschylus’ character portrait.
What is the connection between dreams and the evolution of man?
Aeschylus is perhaps saying that our prehuman ancestors lived their
waking lives in a state akin to our dreaming lives; and that one of
the principal benefits of the development of human intelligence is
our ability to understand the true nature and import of dreams.
There are, it seems, three principal states of mind in human beings:
waking, sleeping and dreaming. An electroencephalograph, which
detects brain waves, records quite distinct patterns of electrical
activity in the brain during these three states.*
* The electroencephalograph (EEG) was invented by a German
psychologist, Hans Berger, whose fundamental interest in the matter
seems to have been telepathy. And, indeed, it can be used for a kind
of radio telepathy; human beings have the capability to turn
particular brain waves-for example, the alpha rhythm-on and off at
will, although this feat requires a little training. With such
training, an individual attached to an electroencephalograph and a
radio transmitter could, in principle, send quite complex messages
in a kind of alpha wave Morse code, merely by thinking them in the
right way; and it is just possible that this method might have some
practical use, such as permitting patients immobilized by severe
stroke to communicate. For historical reasons, non-dreaming sleep is
electroencephalographically characterized as “slow wave sleep,” and
the dream state as ‘-‘paradoxical sleep.”
Brain waves
represent very small currents and voltages produced by the
electrical circuitry of the brain. Typical strengths of such
brain-wave signals are measured in microvolts. Typical frequencies
are between 1 and about 20 Hertz (or cycles per second)-less than
the familiar 60 cycles per second frequency of alternating currents
in electrical outlets in North America.
But what is sleep good for? There is no doubt that if we stay up too
long the body generates neurochemicals that literally force us to go
to sleep. Sleep-deprived animals generate such molecules in their
cerebrospinal fluid, and the cerebrospinal fluid of sleep-deprived
animals induces sleep when injected into other animals who are
perfectly wide awake. There must, then, be a very powerful reason
for sleep.
The conventional answer of physiology and folk medicine alike is
that sleep has a restorative effect; it is an opportunity for the
body to perform mental and physical housekeeping away from the needs
of daily living. But the actual evidence for this view, apart from
its common-sense plausibility, seems to be sparse.
Furthermore, there are some worrisome aspects about the contention.
For example, an animal is exceptionally vulnerable when sleeping.
Granted that most animals sleep in nests, caves, holes in trees or
logs or otherwise recessed or camouflaged locations. Even so, their
helplessness while asleep remains high. Our nocturnal vulnerability
is very evident; the Greeks recognized Morpheus and Thanatos, the
gods of sleep and death, as brothers.
Unless there is some exceptionally strong biological necessity for
sleep, natural selection would have evolved beasts that sleep not.
While there are some animals- the two-toed sloth, the armadillo, the
opossum, and the bat-that, at least in states of seasonal torpor,
sleep nineteen and twenty hours a day, there are others - the common
shrew and Ball’s porpoise-that are said to sleep very little. There
are also human beings who require only one to three hours of sleep a
night.
They take second and third jobs, putter around at night while
their spouses sink into exhaustion, and otherwise seem to lead full,
alert and constructive lives. Family histories suggest that these
predispositions are hereditary. In one case, both a man and his
little daughter are afflicted with this blessing or curse, much to
the groggy consternation of his wife, who has since divorced him for
a novel incompatibility. He retained custody of the daughter. Such
examples suggest that the hypothesis of the recuperative function of
sleep is at best not the whole story.
Yet sleep is very ancient. In the electroencephalographic sense we
share it with all the primates and almost all the other mammals and
birds: it may extend back as far as the reptiles. Temporal-lobe
epilepsy and its accompanying state of unconscious automatic
behavior can be induced in some people by spontaneous electrical
stimulation of the amygdala, deep below the temporal lobe, at
frequencies of a few cycles per second (a few Hertz).
Seizures not
very different from sleep have been reported when an epileptic
patient is driving in an automobile near sunset or sunrise with a
picket fence between him and the sun: at a certain speed the pickets
intercept the sun at just the critical rate to produce a flicker at
the resonant frequency for initiating such seizures. The circadian
rhythm, the daily cycling of physiological function, is known to go
back at least to animals as humble as mollusks. Since a state in
some respects resembling dreaming can be induced by electrical
stimulation of other limbic regions below the temporal lobe, as
described below, centers that initiate both sleep and dreams may not
be far apart in the recesses of the brain.
There is some recent evidence that the two types of sleep, dreaming
and dreamless, depend on the lifestyle of the animal.
Truett Allison and Domenic Ciccheti of Yale University have
found that predators are statistically much more likely to dream
than prey, which are in turn much more likely to experience
dreamless sleep. These studies are all of mammals and apply
only to differences between, not within, species. In dream
sleep, the animal is powerfully immobilized and remarkably
unresponsive to external stimuli. Dreamless sleep is much
shallower, and we have all witnessed cats or dogs cocking their
ears to a sound when apparently fast asleep. It is also
commonly held that when sleeping dogs move their legs in a
kind of running pattern, they are dreaming of the hunt.
The fact
that deep dream sleep is rare among prey today seems clearly
to be a product of natural selection. But organisms that are
largely prey today may have had ancestors that were
predators, and vice versa. Moreover, predators are generally
organisms with larger absolute brain mass and ratio of brain to body
mass than their prey. It makes sense that today, when sleep is
highly evolved, the stupid animals are less frequently immobilized
by deep sleep than the smart ones. But why should they sleep deeply
at all? Why should a state of such deep immobilization ever have
evolved?
Perhaps one useful hint about the original function of sleep is to
be found in the fact that dolphins and whales and aquatic mammals in
general seem to sleep very little. There is, by and large, no place
to hide in the ocean. Could it be that, rather than increasing an
animal’s vulnerability, the function of sleep is to decrease it?
Wilse Webb of the University of Florida and Ray Meddis of London
University have suggested this to be the case. The sleeping style of
each organism is exquisitely adapted to the ecology of the animal.
It is conceivable that animals who are too stupid to be quiet on
their own initiative are, during periods of high risk, immobilized
by the implacable arm of sleep.
The point seems particularly clear
for the young of predatory animals; not only are baby tigers covered
with a superbly effective protective coloration, they also sleep a
great deal. This is an interesting notion and probably at least
partly true. It does not explain everything. Why do lions, who have
few natural enemies, sleep? This question is not a very damaging
objection because lions may have evolved from animals that were not
the king of beasts. Likewise, adolescent gorillas, who have little
to fear, nevertheless construct nests each night-perhaps because
they evolved from more vulnerable predecessors. Or perhaps, once,
the ancestors of lions and gorillas feared still more formidable
predators.
The immobilization hypothesis seems particularly apt in light of the
evolution of mammals, who arose in an epoch dominated by hissing,
thundering and altogether nightmarish reptiles. But nearly all
reptiles are cold-blooded * and, except in the tropics, are forced
into nocturnal immobility. Mammals are warm-blooded and able to
function at night.
*
Robert Bakker, a paleontologist at Harvard University, suggests that
at least some dinosaurs were significantly warm-blooded; even
so, it seems likely that they were not as insensitive to diurnal
temperature change as mammals are, and that they slowed down
substantially at night. Perhaps it was essential for the early
mammals to be immobilized and hidden during the daylight hours that
were ruled by predatory reptiles. I am picturing a late Mesozoic
landscape in which the mammals sleep fitfully by day and the
reptiles by night. But at night even humble carnivorous protomammals
must have posed a real threat to the cold-immobilized reptiles, and
particularly to their eggs.
The nontropical nocturnal ecological niches may
have been almost un-tenanted in the Triassic Period, some two
hundred million years ago.
Indeed, Harry Jerison has suggested that the evolution of
mammals was accompanied by the development of then extremely
sophisticated (and now commonplace) versions of hearing and smell,
senses for perceiving distances and objects at night; and that the
limbic system evolved from the necessity of processing the rich
array of data from these newly elaborated senses.
(A great deal of
the visual-information processing in reptiles is done not in the
brain but in the retina; the optical processing apparatus in the neocortex was largely a later evolutionary development.)
Judged by their endocranial volumes (see figure on page 39), the
dinosaurs were, compared to mammals, remarkably stupid. To take some
“well-known” examples,
Not one approached a chimpanzee in absolute
brain mass; Stegosaurus, which weighed two metric tons, was probably
far more stupid than a rabbit. When the large body weights of the
dinosaurs are taken into account, the smallness of their brains
becomes even more striking:
The ratio of brain to body weight in
Brachiosaurus was ten thousand times smaller than that of man.
Just as sharks are the largest-brained fish for their body
weight, the carnivorous dinosaurs such as Tyrannosaurus were
relatively larger-brained than such herbivores as Diplodocus
and Brachiosaurus. I am sure that Tyrannosaurus was an efficient and
terrifying killing machine. But despite their awesome aspect, the
dinosaurs look vulnerable to dedicated and intelligent
adversaries-such as the early mammals.
Our Mesozoic scene has a curiously vampiric quality with the
carnivorous reptiles hunting the smart sleeping mammals by day, and
the carnivorous mammals hunting the stupid immobile reptiles by
night. While the reptiles buried, their eggs, it is unlikely that
they actively protected either eggs or young. There are very few
accounts of such behavior even in contemporary reptiles, and it is
difficult to picture Tyrannosaurus rex brooding on a clutch of eggs.
For these reasons, the mammals may have won the primordial war of
the vampires; at least some paleontologists believe that the demise
of the dinosaurs was accelerated by nocturnal predation on reptilian
eggs by the early mammals. Two chicken eggs * for breakfast may be
all - at least on the surface - that is left of this ancient mammalian
cuisine.
* In fact, the birds are almost certainly the principal living
descendants of the dinosaurs.
The most intelligent of the dinosaurs by the criterion of brain to
body mass are the Saurornithoides, whose brain mass was typically
about 50 grams to a body mass of about 50 kilograms, placing them
near the ostrich in the figure on page 40. Indeed, they resembled
ostriches. It might be very illuminating to examine fossil endocasts
of their braincases. They probably hunted small animals for food and
used the four fingers of their handlike appendages for many
different tasks.
They are interesting beasts to speculate about. If the dinosaurs
had not all been mysteriously extinguished some sixty-five
million years ago, would the Saurornithoides have continued to
evolve into increasingly intelligent forms? Would they have
learned to hunt large mammals collectively and thus perhaps
have prevented the great proliferation of mammals that
followed the end of the Mesozoic Age? If it had not been for the
extinction of the dinosaurs, would the dominant life forms on
Earth today be descendants of Sauronithoides, writing and reading
books, speculating on what would have happened had the mammals
prevailed? Would the dominant forms think that base 8 arithmetic was
quite natural, but base 10 a frill taught only in the “New Math”?
A great deal of what we consider important about the last few tens
of millions of years of Earth’s history seems to hinge on the
extinction of the dinosaurs. There are literally dozens of
scientific hypotheses that attempt to explain this event, which
appears to have been remarkably rapid and thorough for both land and
water forms. All the explanations proposed seem to be only partly
satisfactory. They range from massive climatic change to mammalian
predation to the extinction of a plant with apparent laxative
properties, in which case the dinosaurs died of constipation.
One of the most interesting and promising hypotheses, first
suggested by I. S. Shklovskii of the Institute for Cosmic Research,
Soviet Academy of Sciences, Moscow, is that the dinosaurs died
because of a nearby supernova event - the explosion of a dying star
some tens of light-years away, which resulted in an immense flux of
high energy charged particles that entered our atmosphere, changed
its properties, and, perhaps by destroying the atmospheric ozone,
let in lethal quantities of solar ultraviolet radiation.
Nocturnal
animals, such as the mammals of the time, and deep-sea animals, such
as fish, could have survived this higher ultraviolet intensity; but
daytime animals that lived on land or near the surface of the waters
would have been preferentially destroyed. Such a disaster would be
aptly named- the word itself means “bad star.”
If this sequence of events is correct, the major course of
biological evolution on the Earth in the last sixty-five million
years, and indeed the very existence of human beings, can be traced
to the death of a distant sun. Perhaps other planets circled that
star; perhaps one of those planets enjoyed a thriving biology
tortuously evolved over billions of years. The supernova explosion
would surely have extinguished all life on that planet and probably
even driven its atmosphere into space.
Do we owe our existence to a mighty stellar catastrophe that
elsewhere destroyed biospheres and worlds?
After the extinction of the dinosaurs, mammals moved into daytime
ecological niches. The primate fear of the dark must be a
comparatively recent development. Washburn has reported that infant
baboons and other young primates appear to be born with only three
inborn fears-of falling, snakes, and the dark-corresponding
respectively to the dangers posed by Newtonian gravitation to
tree-dwellers, by our ancient enemies the reptiles, and by mammalian
nocturnal predators, which must have been particularly terrifying
for the visually oriented primates.
If the vampiric hypothesis is true - and it is at hest a likely
hypothesis-the function of sleep is built deeply into the mammalian
brain; from earliest mammalian times, sleep played a fundamental
role in survival. Since for primitive mammals sleepless nights would
have been more dangerous for the survival of the taxon than sexless
nights, sleep should be a more powerful drive than sex-which, at
least in most of us, it seems to be.
But eventually mammals evolved
to a point where sleep could be modified by changed circumstances.
With the extinction of the dinosaurs, daylight suddenly became a
benevolent environment for the mammals. Daytime immobilization was
no longer compulsory, and a wide variety of sleep patterns slowly
developed, including the contemporary correlation of mammalian
predators with extensive dreaming and mammalian prey with a more
watchful dreamless sleep. Perhaps those people who can do with only
a few hours’ sleep a night are the harbingers of a new human
adaptation that will take full advantage of the twenty-four hours of
the day. I, for one, freely confess envy for such an adaptation.
These conjectures on the origins of the mammals constitute a
kind of scientific myth: they may have some germ of truth in
them, but they are unlikely to be the whole story. That
scientific myths make contact with more ancient myths may or
may not be a coincidence. It is entirely possible that we are
able to invent scientific myths only because we have previously
been exposed to the other sort. Nevertheless, I cannot resist
connecting this account of the origin of mammals with another
curious aspect of the Genesis myth of the exile from Eden. Because
it is a reptile, of course, that offers the fruit of the knowledge
of good and-evil-abstract and moral neocortical functions - to Adam
and Eve.
There are today a few remaining large reptiles on Earth, the most
striking of which is the Komodo dragon of Indonesia: cold-blooded,
not very bright, but a predator exhibiting a chilling fixity of
purpose. With immense patience, it will stalk a sleeping deer or
boar, then suddenly slash a hind leg and hang on until the prey
bleeds to death. Prey is tracked by scent, and a hunting dragon
lumbers and sashays, head down, its forked tongue flicking over the
ground for chemical traces.
The largest adults weigh about 135
kilograms (300 pounds), are three meters (about 10 feet) long and
live perhaps to be centenarians. To protect its eggs, the dragon
digs trenches from two to as much as nine meters (almost 30 feet)
deep-probably a defense against egg-eating mammals (and themselves:
Adults are known occasionally to stalk a nest-hole, waiting for the
newly hatched young to emerge and provide a little delicacy for
lunch). As another clear adaptation to predators, the dragon
hatchlings live in trees.
The remarkable elaboration of these adaptations shows clearly that
dragons are in trouble on the planet Earth. The Komodo dragon lives
in the wild only in the Lesser Sunda Islands.* There are only about
2,000 of them left. The obscurity of their locale immediately
suggests that dragons are near extinction because of mammalian,
chiefly human, predation, a conclusion borne out by their history
over the last two centuries.
* It is in the Greater Sunda Islands-more specifically Java - that
the first specimen of Homo erectus, with an endocranial volume of
almost 1,000 cc, was found by E. Dubok in 1891.
All dragons with less extreme
adaptations or less remote habitats are dead. I even wonder whether
the systematic separation of brain mass for a given body mass
between mammals and reptiles (see chart on page 39) might not be the
result of a systematic extinction of bright dragons by mammalian
predators. In any case, it is very likely that the population of
large reptiles has been declining steadily since the end of the
Mesozoic Age, and that there were many more of them even one or two
thousand years ago than there are today.
The pervasiveness of dragon myths in the folk legends of many
cultures is probably no accident.*
* Curiously, the first representative skull of Pelting man- the Homo
erectus whose remains are clearly associated with the use of fire.
The implacable mutual hostility between man and dragon, as
exemplified in the myth of St. George, is strongest in the West. (In
chapter 3 of the Book of Genesis, God ordains an eternal enmity
between reptiles and humans.) But it is not a Western anomaly. It is
a worldwide phenomenon.
-
Is it only an accident that the common human
sounds commanding silence or attracting attention seem strangely
imitative of the hissing of reptiles?
-
Is it possible that dragons
posed a problem for our protohuman ancestors of a few million years
ago, and that the terror they evoked and the deaths they caused
helped bring about the evolution of human intelligence?
-
Or does the
metaphor of the serpent refer to the use of the aggressive and
ritualistic reptilian component of our brain in the further
evolution of the neocortex?
With one exception, the Genesis account
of the temptation by a reptile in Eden is the only instance in the
Bible of humans understanding the language of animals. When we
feared the dragons, were we fearing a part of ourselves? One way or
another, there were dragons in Eden, in Sinkiang Province, China, in
a place called the Mountain of Dragons.
The most recent dinosaur fossil is dated at about sixty million
years ago. The family of man (but not the genus Homo) is some
tens of millions of years old. Could there have been manlike
creatures who actually encountered Tyrannosaurus rex? Could
there have been dinosaurs that escaped the extinctions in the
late Cretaceous Period? Could the pervasive dreams and
common fears of “monsters,” which children develop shortly
after they are able to talk, be evolutionary vestiges of quite
adaptive-baboonlike-responses to dragons and owls?
*
* Since writing this passage I have discovered that Darwin expressed
a similar thought: “May we not suspect that the vague but very real
fears of children, which are quite independent of experience, are
inherited effects of real dangers and abject superstitions during
ancient savage times? It is quite conformable with what we know of
the transmission of formerly well-developed characters, that they
should appear at an early period of life, and afterwards
disappear-like gill slits in human embryology.”
What functions do dreams serve today? One view, published in a
reputable scientific paper, holds that the function of dreams is to
wake us up a little, every now and then, to see if anyone is about
to eat us. But dreams occupy such a relatively small part of normal
sleep that this explanation does not seem very compelling. Moreover,
as we have seen, the evidence points just the other way: today it is
the mammalian predators, not the mammalian prey, who
characteristically have dream-filled sleep.
Much more plausible is
the computer-based explanation that dreams are a spillover from the
unconscious processing of the day’s experience, from the brain’s
decision on how much of the daily events temporarily stored in a
kind of buffer to emplace in long-term memory. The events of
yesterday frequently run through my dreams; the events of two days
ago, much more rarely. However, the buffer-dumping model seems
unlikely to be the whole story, because it does not explain the
disguises that are so characteristic of the symbolic language of
dreams, a point first stressed by Freud. It also does not explain
the powerful affect or emotions of dreams; I believe there are many
people who have been far more thoroughly frightened by their dreams
than by anything they have ever experienced while awake.
The buffer-dumping and memory-storage functions of dreams
have some interesting social implications. The American
psychiatrist Ernest Hartmann of Tufts University has provided
anecdotal but reasonably persuasive evidence that people who
are engaged in intellectual activities during the day, especially
unfamiliar intellectual activities, require more sleep at night,
while, by and large, those engaged in mainly repetitive and
intellectually unchallenging tasks are able to do with much less
sleep.
However, in part for reasons of organizational convenience,
modern societies are structured as if all humans had the same sleep
requirements; and in many parts of the world there is a satisfying
sense of moral rectitude in rising early. The amount of sleep
required for buffer dumping would then depend on how much we have
both thought and experienced since the last sleep period. (There is
no evidence that the causality runs backwards: people drugged with phenobarbital are not reported, during interstitial waking periods,
to perform unusual intellectual accomplishments.)
In this respect it
would be interesting to examine individuals with very low sleep
needs to determine whether the fraction of sleep time they spend
dreaming is larger than it is for those with normal sleep
requirements, and to determine whether their amount of sleep and
dream time increases with the quality and quantity of their learning
experiences while awake.
Michel Jouvet, a French neurologist at the University of Lyons, has
found that dream sleep is triggered in the pons, which, while it
resides in the hindbrain, is a late and essentially mammalian
evolutionary development. On the other hand, Penfield has found that
electrical stimulation deep into and below the temporal lobe in the neocortex and limbic complex can produce a waking state in
epileptics very similar to that of dreams denuded of their symbolic
and fantastic aspects. It can also induce the deja vu experience.
Much of dream affect, including fear, can also be induced by such
electrical stimulation.
I once had a dream that will tantalize me forever. I dreamt I was
idly thumbing through a thick history text. I could tell from the
illustrations that the work was moving slowly, in the usual
manner of such textbooks, through the centuries: classical
times, Middle Ages, Renaissance and so on, gradually
approaching the modern era. But then there was World War II
with about two hundred pages left. With mounting excitement I
worked my way more deeply into the work until I was sure that I had
passed my own time.
It was a history book that included the
future-like turning the December 31 page of the Cosmic Calendar and
finding a fully detailed January 1. Breathlessly I attempted
literally to read the future. But it was impossible. I could make
out individual words. I could even discern the serifs on the
individual characters. But I could not put the letters together into
words or words’ together into sentences. I was alexic.
Perhaps this is simply a metaphor of the unpredictability of the
future. But my invariable dream experience is that I am unable to
read, I can recognize, for example, a stop sign by its color and its
octagonal shape, but I cannot read the word STOP, although I know it
is there. I have the impression of understanding the meaning of a
page of type, but not by reading it word by word or sentence by
sentence. I cannot reliably perform even simple arithmetic
operations in the dream state. I make a variety of verbal confusions
of no apparent symbolic significance, like mixing up Schumann and
Schubert. I am a little aphasic and entirely alexic. Not everyone I
know has the same cognitive impairment in the dream state, but
people often have some impairment. (Incidentally, individuals who
are blind from birth have auditory, not visual dreams.) The
neocortex is by no means altogether turned off in the dream state,
but it certainly seems to suffer important malfunctions.
The seeming fact that mammals and birds both dream while
their common ancestor, the reptiles, do not is surely
noteworthy. Major evolution beyond the reptiles has been
accompanied by and perhaps requires dreams. The electrically
distinctive sleep of birds is episodic and brief. If they dream,
they dream for only about a second at a time. But birds are, in
an evolutionary sense, much closer to reptiles than mammals
are. If we knew only about mammals, the argument would be
more shaky; but when both major taxonomic groups that have
evolved from the reptiles find themselves compelled to dream,
we must take the coincidence seriously. Why should an animal
that has evolved from a reptile have to dream while other
animals do not? Could it be because
the reptilian brain is still
present and functioning?
It is extremely rare in the dream state that we bring ourselves up
short and say, “This is only a dream.” By and large we invest the
dream content with reality. There are no rules of internal
consistency that dreams are required to follow. The dream is a world
of magic and ritual, passion and anger, but very rarely of
skepticism and reason. In the metaphor of the triune brain, dreams
are partially a function of the R-complex and the limbic cortex, but
not of the rational part of the neocortex.
Experiments suggest that as the night wears on our dreams engage
increasingly earlier material from our past, reaching back to
childhood and infancy. At the same time the primary process and
emotional content of the dream also increase. We are much more
likely to dream of the passions of the cradle just before awakening
than just after falling asleep. This looks very much as if the
integration of the day’s experience into our memory, the forging of
new neural links, is either an easier or a more urgent task. As the
night wears on and this function is completed, the more affecting
dreams, the more bizarre material, the fears and lusts and other
powerful emotions of the dream material emerge. Late at night, when
it is very still and the obligatory daily dreams have been dreamt,
the gazelles and the dragons begin to stir.
One of the most significant tools in studying the dream state
was developed by William Dement, a Stanford University
psychiatrist, who is as sane as it is possible for a human being
to be, but who bears an exceedingly interesting name for a man
of his profession. The dream state is accompanied by rapid eye
movements (REM), which can be detected by electrodes taped
lightly over the eyelids in sleep, and by a particular brain wave
pattern on the EEG. Dement has found that everyone dreams
many times each night. On awakening, an individual in the midst
of REM sleep will usually remember his dream.
Even people
who claim never to dream have been discovered by REM and
EEG criteria to dream as much as anyone else; and, when
awakened at appropriate times, they admit with some surprise to
having dreamt. The human brain is in a distinct physiological state
while dreaming, and we dream rather often. While perhaps 20 percent
of the subjects awakened during REM sleep do not recall their
dreams, and some perhaps 10 percent of subjects awakened during
non-REM sleep report dreams, we will, for convenience, identify REM
and accompanying EEG patterns with the dream state.
There is some evidence that dreaming is necessary. When people or
other mammals are deprived of REM sleep (by awakening them as soon
as the characteristic REM and EEG dream patterns emerge), the number
of initiations of the dream state per night goes up, and, in severe
cases, daytime hallucinations-that is, waking dreams-occur. I have
mentioned that the REM and EEC patterns of dreams are brief in birds
and absent in reptiles. Dreams seem to be primarily a mammalian
function. What is more, dream sleep is most vigorously engaged in by
human beings in the early postnatal period.
Aristotle stated quite
positively that infants do not dream at all. On the contrary, we
find they may be dreaming most of the time. Full-term newborn babies
spend more than half their sleep time in the REM dream state. In
infants born a few weeks premature, the dream time is three-quarters
or more of the total sleep time. Earlier in its intrauterine
existence, the fetus may be dreaming all the time. (Indeed, newborn
kittens are observed to spend all of their sleep time in the REM
stage.) Recapitulation would then suggest that dreaming is an
evolutionarily early and basic mammalian function.
There is another connection between infancy and dreams: both
are followed by amnesia. When we emerge from either state,
we have great difficulty remembering what we have
experienced. In both cases, I would suggest, the left
hemisphere of the neocortex, which is responsible for analytic
recollection, has been functioning ineffectively. An alternative
explanation is that in both dreams and early childhood we
experience a kind of traumatic amnesia: The experiences are
too painful to remember. But many dreams we forget are very
pleasant, and it is difficult to believe that infancy is that
unpleasant. Also some children seem capable of remembering
extremely early experiences.
Memories of events late in the first
year of life are not extremely rare, and there are possible examples
of even earlier recollections. At age three, my son Nicholas was
asked for the earliest event he could recall and replied in a hushed
tone while staring into middle distance, “It was red, and I was very
cold.” He was born by Caesarean section. It is probably very
unlikely, but I wonder whether this could just possibly be a true
birth memory.
At any rate, I think it is much more likely that childhood and dream
amnesia arise from the fact that in those states our mental lives
are determined almost entirely by the R-complex, the limbic system
and the right cerebral hemisphere. In earliest childhood, the neocortex is underdeveloped; in amnesia, it is impaired.
There is a striking correlation of penile or clitoral erection with
REM sleep, even when the manifest dream content has no overt sexual
aspects whatever. In primates, such erections are connected with sex
(of course!), aggression and the maintenance of social hierarchies.
I think that when we dream there is a part of us engaged in
activities rather like those of the squirrel monkeys I saw in Paul
MacLean’s laboratory. The R-complex is functioning in the dreams of
humans; the dragons can be heard, hissing and rasping, and the
dinosaurs thunder still.
One excellent test of the merit of scientific ideas is their
subsequent validation. A theory is put forward on fragmentary
evidence, then an experiment is performed, the outcome of
which the proposer of the theory could not know. If the
experiment confirms the original idea, this is usually taken as
strong support for the theory. Freud held that the great
majority, perhaps all, of the “psychic energy” of our
primary-process emotions and dream material is sexual in
origin.
The absolutely essential role of sexual interest in
providing for the propagation of the species makes this idea
neither as silly nor as depraved as it appeared to many of
Freud’s Victorian contemporaries. Carl Gustav Jung, for
example, held that Freud had severely overstated the primacy
of sex in the affairs of the unconscious. But now, three-quarters of
a century later, experiments in the laboratories of Dement and other
psychologists appear to support Freud. It would, I think, require a
very dedicated puritanism to deny some connection between penile or
clitoral erection and sex.
It seems to follow that sex and dreams
are not casually or incidentally connected but rather have deep and
fundamental ties-although dreams certainly partake of ritual,
aggressive and hierarchical material as well. Particularly
considering the state of sexual repression in
late-nineteenth-century Viennese society, many of Freud’s insights
seem hard-won and courageous as well as valid.
Statistical studies have been made of the most common
categories of dreams-studies which, at least to some extent,
ought to illuminate the nature of dreams. In a survey of the
dreams of college students, the following were, in order, the
five most frequent types:
(1) falling
(2) being pursued or
attacked
(3) attempting repeatedly and unsuccessfully to
perform a task
(4) various academic learning experiences
(5) diverse sexual experiences
Number (4) on this list seems of
special and particular concern to the group being sampled. The
others, while sometimes actually encountered in the lives of
undergraduates, are likely to be applicable generally, even to
non-students.
The fear of falling seems clearly connected with our arboreal
origins and is a fear we apparently share with other primates. If
you live in a tree, the easiest way to die is simply to forget the
danger of falling. The other three categories of most common
dreams are particularly interesting because they correspond to
aggressive, hierarchical, ritualistic and sexual functions -the
realm of the R-complex. Another provocative statistic is that
almost half of the people queried reported dreams about
snakes, the only nonhuman animal rating a category all to itself
in the twenty most common dreams.
It is, of course, possible
that many snake dreams have a straightforward Freudian
interpretation. However, two-thirds of the respondents
reported explicitly sexual dreams. Since, according to
Wash-burn, young primates exhibit an untaught fear of snakes,
it is easy to wonder whether the dream world does not point directly
as well as indirectly to the ancient hostility between reptiles and
mammals.
There is one hypothesis that seems to me consistent with all the
foregoing facts: The evolution of the limbic system involved a
radically new way of viewing the world. The survival of the early
mammals depended on intelligence, daytime unobtrusiveness, and
devotion to the young. The world as perceived through the R-complex
was quite a different world. Because of the accretionary nature of
the evolution of the brain, R-complex functions could be utilized or
partially bypassed but not ignored.
Thus, an inhibition center
developed below what in humans is the temporal lobe, to turn off
much of the functioning of the reptilian brain; and an activation
center evolved in the pons to turn on the R-complex, but harmlessly,
during sleep. This view, of course, has some notable points of
similarity to Freud’s picture of the repression of the id by the
superego (or of the unconscious by the conscious), with expressions
of the id made most clearly manifest in slips of the tongue, free
associations, dreams and the like-that is, during the interstices of
superego repression.
With the large-scale development of the neocortex in higher mammals
and primates, some neocortical involvement in the dream state
developed-a symbolic language is, after all, still a language. (This
is related to the different functions of the two hemispheres of the
neocortex, described in the following chapter.) But the dream
imagery contained significant sexual, aggressive, hierarchical and
ritualistic elements. The fantastic material in the dream world may
be connected with the near-absence of direct sensory stimulation
during dreams.
There is very little reality testing in the dream state. The
prevalence of dreams in infants would, in this view, be because,
in infancy, the
There is one hypothesis that seems to me consistent with all
the foregoing facts: The evolution of the limbic system involved
a radically new way of viewing the world. The survival of the
early mammals depended on intelligence, daytime
unobtrusiveness, and devotion to the young. The world as
perceived through the R-complex was quite a different world.
Because
of the accretionary nature of the evolution of the brain, R-complex
functions could be utilized or partially bypassed but not ignored.
Thus, an inhibition center developed below what in humans is the
temporal lobe, to turn off much of the functioning of the reptilian
brain; and an activation center evolved in the pons to turn on the
R-complex, but harmlessly, during sleep. Tins view, of course, has
some notable points of similarity to-Freud’s picture of the
repression of the id by the superego (or of the unconscious by the
conscious), with expressions of the id made most clearly manifest in
slips of the tongue, free associations, dreams and the like-that is,
during the interstices of superego repression.
With the large-scale development of the neocortex in higher mammals
and primates, some neocortical involvement in the dream state
developed-a symbolic language is, after all, still a language. (This
is related to the different functions of the two hemispheres of the
neocortex, described in the following chapter.) But the dream
imagery contained significant sexual, aggressive, hierarchical and
ritualistic elements, fantastic material in the dream world may be
connected with the near-absence of direct sensory stimulation during
dreams. There is very little reality testing in the dream state.
The
prevalence of dreams in infants would, in this view, be because, in
infancy, the analytic part of the neocortex is barely working. The
absence of dreams in reptiles would be because there is no
repression of the dream state in reptiles; they are, as Aeschylus
described our ancestors, “dreaming” in their waking state. I believe
this idea can explain the strangeness-that is, the differences from
our waking verbal consciousness-of the dream state; its mammalian
and human neonatal localization; its physiology; and its
pervasiveness in man.
We are descended from reptiles and mammals
both. In the daytime repression of the R-complex and in the
nighttime stirring of the dream dragons, we may each of us be
replaying the hundred-million-year-old warfare between the reptiles
and the mammals. Only the times of day of the vampiric hunt have
been reversed.
Human beings exhibit enough reptilian behavior as it is. If we
gave full rein to the reptilian aspects of our nature, we would
clearly have a low survival potential. Because the R-complex is
woven so intimately into the fabric of the brain, its functions
cannot be entirely avoided for long. Perhaps the dream state
permits, in our fantasy and its reality, the R-complex to function
regularly, as if it were still in control.
If this is true, I
wonder, after Aeschylus, if the waking state of other mammals is
very much like the dream state of humans-where we can recognize
signs, such as the feeling of running water and the smell of
honeysuckle, but have an extremely limited repertoire of symbols
such as words; where we encounter vivid sensory and emotional images
and active intuitive understanding, but very little rational
analysis; where we are unable to perform tasks requiring extensive
concentration; where we experience short attention spans and
frequent distractions and, most of all, a very feeble sense of
individuality or self, which gives way to a pervading fatalism, a
sense of unpredictable buffeting by uncontrollable events.
If this
is where we have come from, we have come very far.
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