[*] Address before the American Philosophical Society, Philadelphia,
April 22, 1911.
The surgeon is familiar with the manifestations of every variety
of the human emotions in the various stations of life, from infancy
to senility, in health and in disease. Not only does he come
into intimate contact with the emotions displayed by the victims
of disease and of accidents, but he also observes those manifested
by the relatives and friends of the families of his patients.
Moreover, he is unhappily forced to notice the emotional effect
upon himself when he is waging an unequal battle against death--
the strain and worry at a crisis, when a life is in the balance
and a single false move may be fatal, is an experience known only
to the operating surgeon.
For the data for this paper, therefore, in which I shall for the most
part limit my discussion to the strongest of all emotions--FEAR--I have
drawn largely from my personal experience as a surgeon, as well
as from an experimental research in which I have had the valuable
assistance of my associates, Dr. H. G. Sloan, Dr. J. B. Austin,
and Dr. M. L. Menten.
I believe it can be shown that it is possible to elicit the emotion
of fear only in those animals that utilize a motor mechanism
in defense against danger or in escape from it. For example,
the defense of the skunk is a diabolic odor which repels its enemies;
the skunk has no adequate equipment for defense or escape by
muscular exertion, and the skunk therefore shows little or no fear.
Again, certain species of snakes are protected by venom;
they possess no other means of defense nor have they adequate
motor mechanisms for escape and they show no fear. Because of
their strength other animals, such as the lion, the grizzly bear,
and the elephant, show but little fear (Fig. 6). Animals which have
an armored protection, such as the turtle, show little fear.
It is, therefore, obvious that fear is not universal and that the
emotion of fear is felt only by those animals whose self-preservation
is dependent upon an uncertain adequacy of their power of muscular
exertion either for defense or for flight (Fig. 7).
What are the principal phenomena of fear? They are palpitation
of the heart, acceleration of the rate and alteration of the rhythm
of the respiration, cold sweat, rise in body temperature,
tremor, pallor, erection of the hair, suspension of the principal
functions of digestion, muscular relaxation, and staring of the eyes
(Fig. 12). The functions of the brain are wholly suspended except those
which relate to the self-protective response against the feared object.
Neither the brain nor any other organ of the body can respond
to any other lesser stimulus during the dominance of fear.
From these premises it would appear that under the influence
of fear, most, perhaps all, of the organs of the body are divided
sharply into two classes: First, those that are stimulated,
and, second, those that are inhibited. Those that are stimulated
are the entire muscular system, the vasomotor and locomotor systems,
the senses of perception, the respiration, the mechanism for erecting
the hair, the sweat-glands, the thyroid gland, the adrenal gland
(Cannon), and the special senses. On the other hand,
all the digestive and procreative functions are inhibited.
What is the significance of this stimulation of some and inhibition
of other organs? As far as we know, the stimulated organs
increase the efficiency of the animal for fight or for flight.
It is through skeletal muscles that the physical attack or escape
is effected; these muscles alone energize the claws, the teeth,
the hoofs, and the means for flight. The increased action of the
muscles of the heart and the blood-vessels increases the efficiency
of the circulation; the secretion of the adrenal gland causes a rise
in the blood-pressure; the increased action of the thyroid gland causes
an increased metabolic activity; there is evidence that glycogen
is actively called out, this being the most immediately available
substance for the production of energy; the increased activity
of the respiration is needed to supply the greater need of oxygen
and the elimination of the increased amount of waste products;
the dilatation of the nostrils affords a freer intake of air;
the increased activity of the sweat-glands is needed to regulate
the temperature of the body which the increased metabolism causes to rise.
The activity of all the organs of perception--sight, hearing, smell--
is increased in order that the danger may be more accurately perceived.
It cannot be a mere coincidence that the organs and the tissues
that are stimulated in the emotion of fear are precisely those that
are actually utilized in a physical struggle for self-preservation.
Are any other organs stimulated by fear except those that can
or that do assist in making a defensive struggle? I know of none.
On the other hand, if an animal could dispense with his bulky
digestive organs, whose functions are suspended by fear, if he could,
so to speak, clear his decks for battle, it would be to his advantage.
Although the marvelous versatility of natural selection apparently
could devise no means of affording this advantage, it nevertheless shut
off the nervous current and saved the vital force which is ordinarily
consumed by these non-combatants in the performance of their functions.
Whatever may be the origin of fear, its phenomena are due to a
stimulation of all the organs and tissues that add to the efficiency
of the physical struggle for self-preservation and an inhibition
of the func-
{illust. caption = FIG. 19--THE BROAD JUMP. Note the similarity
of the expression to the facial expression of fear and of anger
(Figs. 12 and 21). (Wm. J. Brownlow, drawn from photo.)
tions of the leading organs that do not participate in that struggle--
the non-combatants, so to speak. Fear arose from injury,
and is one of the oldest and surely the strongest emotion.
By the slow process of vast empiricism nature has evolved the
wonderful defensive motor me-chanism of many animals and of man.
The stimulation of this mechanism leading to a physical struggle is action,
and the stimulation of this mechanism without action is emotion.
We may say, therefore, that fear is a PHYLOGENETIC FIGHT OR FLIGHT (Fig.
18). On this hypothesis all the organs and parts {illust. caption
= FIG. 20.-FINISH OF RELAY RACE.
Compare the facial expression of the runners with those in Figs.
12, 19, 22. These pictures illustrate the fact that the same
mechanism is stimulated in emotion as in physical action.
(Photo by Underwood and Underwood, N. Y.)}
of the body are integrated, connected, or correlated for the
self-preservation of the individual by the activity of his motor mechanism
(Figs. 12, 19, and 20). We fear not in our hearts alone, not in our
brains alone, not in our viscera alone--fear influences every organ
and tissue; each organ or tissue is stimulated or inhibited according
to its use or hindrance in the physical struggle for existence.
By thus concentrating all or most of the nerve force on the nerve-muscular
mechanism for defense, a greater physical power is developed.
Hence it is that under the stimulus of fear animals are able to perform
preternatural feats of strength. For the same reason, the exhaustion
following fear will be increased as the powerful stimulus of fear drains
the cup of nervous energy even though no visible action may result.
An animal under the stimulus of fear may be likened to an automobile
with the clutch thrown out but whose engine is racing at full speed.
The gasoline is being consumed, the machinery is being worn,
but the machine as a whole does not move, though the power of its
engine may cause it to tremble.
When this conception is applied to the human beings of today,
certain mysterious phenomena are at once elucidated. It must be borne
in mind that man has not been presented with any new organs to meet
the requirements of his present state of civilization; indeed, not only
does he possess organs of the same type as those of his savage fellows,
but of the same type also as those possessed by the lower animals even.
In fact, man has reached his present status of civilization with
the primary equipment of brutish organs. Perhaps the most striking
difference between man and animals lies in the greater control
which man has gained over his primitive instinctive reactions.
As compared with the entire duration of organic evolution,
man came down from his arboreal abode and assumed his new role
of increased domination over the physical world but a moment ago.
And now, though sitting at his desk in command of the complicated
machinery of civilization, when he fears a business catastrophe
his fear is manifested in the terms of his ancestral physical battle
in the struggle for existence. He cannot fear intellectually,
he cannot fear dispassionately, he fears with all his organs,
and the same organs are stimulated and inhibited as if, instead of it
being a battle of credit, of position, or of honor, it were a physical
battle with teeth and claws. Whether the cause of acute fear
be moral, financial, social, or stage fright, the heart beats wildly,
the respirations are accelerated, perspiration is increased,
there are pallor, trembling, indigestion, dry mouth, etc.
The phenomena are those which accompany physical exertion
in self-defense or escape. There is not one group of phenomena
for the acute fear of the president of a bank in a financial
crash and another for the hitherto trusted official who suddenly
and unexpectedly faces the imminent probability of the penitentiary;
or one for a patient who unexpectedly finds he has a cancer
and another for the hunter when he shoots his first big game.
Nature has but one means of response to fear, and whatever its cause
the phenomena are always the same--always physical.
If the stimulus of fear be repeated from day to day, whether in
the case of a mother anxious on account of the illness of a child;
a business man struggling against failure; a politician under contest
for appointment; a broker in the daily hazard of his fortune;
litigants in legal battle, or a jealous lover who fears a rival;
the countless real as well as the baseless fears in daily life,
in fact, all forms of fear, as it seems to me, express themselves
in like terms of ancestral physical contests. On this law,
fear dominates the various organs and parts of the body.
Anger and fear express opposite emotional states. Fear is the
expression of a strong desire to escape from danger; anger, of a
strong desire to attack physically and to vanquish opposition.
This hypothesis is strongly supported by the outward expressions
of fear and of anger. When the business man is conducting a struggle
for existence against his rivals, and when the contest is at
its height, he may clench his fists, pound the table, perhaps show
his teeth, and exhibit every expression of physical combat.
Fixing the jaw and showing the teeth in anger merely emphasize
the remarkable tenacity of phylogeny. Although the development
of the wonderful efficiency of the hands has led to a modification
of the once powerful canines of our progenitors, the ancestral use
of the teeth for attack and defense is attested in the display of anger.
In all stations of life differences of opinion may lead to argument
and argument to physical combats, even to the point of killing.
The physical violence of the savage and of the brute still lies
surprisingly near the surface (Fig. 21).
We have now presented some of the reasons based largely on gross animal
behavior why fear is to be regarded as a response to phylogenetic
association with physical danger. In further support of this hypothesis,
I shall now present some clinical and experimental evidence.
Although there is not convincing proof, yet there is evidence that
the effect of the stimulus of fear upon the body when unaccompanied
by physical activity is more injurious than is an actual physical
contest which results in fatigue without gross physical injury.
It is well known that the soldier who, while under fire,
waits in vain for orders to charge, suffers more than the soldier
who flings himself into the fray; and that a wild animal endeavoring
to avoid capture suffers less than one cowering in captivity.
An unexpressed smouldering emotion is measurably relieved by action.
It is probable that the various energizing substances needed in
physical combat, such as the secretions of the thyroid, the adrenals
(Cannon), etc., may cause physical injury to the body when they
are not consumed by action (Fig. 22).
That the brain is definitely influenced--damaged even--
by fear has been proved by the following experiments:
Rabbits were frightened by a dog but were neither injured nor chased.
After various periods of time the animals were killed and their
brain-cells compared with the brain-cells of normal animals--
wide-spread changes were seen (Fig. 13). The principal clinical phenomena
expressed by the rabbit were rapid heart, accelerated respiration,
prostration, tremors, and a rise in temperature. The dog showed
similar phenomena, excepting that, instead of such muscular relaxation
as was shown by the rabbit, it exhibited aggressive muscular action.
Both the dog and the rabbit were exhausted but, although the dog
exerted himself actively and the rabbit remained physically passive,
the rabbit was much more exhausted.
Further observations were made upon the brain of a fox
which had been chased for two hours by members of a hunt club,
and had been finally overtaken by the hounds and killed.
Most of the brain-cells of this fox, as compared with those of a
normal fox, showed extensive physical changes (Fig. 4).
The next line of evidence is offered with some reservation,
but it has seemed to me to be more than mere idle speculation.
It relates to the phenomena of one of the most interesting diseases
in the entire category of human ailments--I refer to exophthalmic goiter,
or Graves' disease, a disease primarily involving the emotions.
This disease is frequently the direct sequence of severe
mental shock or of a long and intensely worrying strain.
The following case is typical: A broker was in his usual health up
to the panic of 1907; during this panic his fortune and that of others
were for almost a year in jeopardy, failure finally occurring.
During this heavy strain he became increasingly nervous and by
imperceptible degrees there developed a pulsating enlargement of
the thyroid gland, an increased prominence of the eyes, marked increase
in perspiration--profuse sweating even--palpitation of the heart,
increased respiration with frequent sighing, increase in blood-pressure;
there were tremor of many muscles, rapid loss of weight and strength,
frequent gastro-intestinal disturbances, loss of normal control
of his emotions, and marked impairment of his mental faculties.
He was as completely broken in health as in fortune.
These phenomena resembled closely those of fear and followed
in the wake of a strain which was due to fear.
In young women exophthalmic goiter often follows in the wake
of a disappointment in love; in women, too, it frequently follows
the illnesses of children or parents during which they have had
to endure the double strain of worry and of constant care.
Since such strains usually fall most heavily upon women, they are
the most frequent victims of this disease. Now, whatever the exciting
cause of exophthalmic goiter, whether it be unusual business worry,
disappointment in love, a tragedy, or the illness of a loved one,
the symptoms are alike and closely resemble the phenomena of one
of the great primitive emotions. How could disappointment in love
play a role in the causation of Graves' disease? If the hypothesis
which has been presented as an explanation of the genesis and
the phenomena of fear be correct, then that hypothesis explains
also the emotion of love. If fear be a phylogenetic physical
defense or escape which does not result in muscular action,
then love is a phylogenetic conjugation without physical action.
The quickened pulse, the leaping heart, the accelerated respiration,
the sighing, the glowing eye, the crimson cheek, and many other
phenomena are merely phylogenetic recapitulations of ancestral acts.
The thyroid gland is believed to participate in such physical activities.
Hence it may well follow that the disappointed maiden who is intensely
integrated for a youth will, at every thought of him, be subjected
by phylogenetic association to a specific stimulation analogous
to that which attended the ancestral consummation. Moreover, a happy
marriage has many times been followed by a cure of the exophthalmic
goiter which appeared in the wake of such an experience.
The victims of Graves' disease present a counterpart of
emotional exhaustion. That the emotions in Graves' disease are
abnormally acute is illustrated by my personal observation
of the death of a subject of this disease from fear alone.
Whatever the exciting cause of this disease, the symptoms are the same;
just as in fear, the phenomena are the same whatever the exciting cause.
Figures 12 and 16 show the resemblance between the outward appearances
of a patient with Graves' disease and of a person obsessed by fear.
Fear and Graves' disease have the following phenomena in common:
Increased heart-beat, increased respiration, rising temperature,
muscular tremors, protruding eyes, loss in weight; Cannon has found
an increased amount of adrenalin in the blood in fear and Frankel
in Graves' disease; increased blood-pressure; muscular weakness;
digestive disturbances; impaired nervous control; hypersusceptibility
to stimuli; in protracted intense fear the brain-cells show marked
physical changes, and in Graves' disease analogous changes are seen
(Figs. 13 C and 15). In Graves' disease there seems to be a composite
picture of an intense expression of the great primitive emotions.
If Graves' disease be a disease of the great primitive emotions,
or rather of the whole motor mechanism, how is the constant flow
of stimulation of this complicated mechanism supplied? It would
seem that there must be secreted in excessive amount some substance
that activates the motor mechanism. The nervous system in Graves'
disease is hypersusceptible to stimuli and to thyroid extract.
It might follow that even a normal amount of thyroid secretion would
lead to excessive stimulation of the hypersusceptible motor mechanism.
This condition of excessive motor activity and hyperexcitability may
endure for years. What is the source of this pathologic excitation?
The following facts may give a clue. In suitable cases of Graves'
disease, if the thyroid secretion is sufficiently diminished by a removal
of a part of the gland or by interrupting the nerve and the blood supply,
the phenomena of the disease are diminished immediately, and in favorable
cases the patient is restored to approximately the normal condition.
The heart action slows, the respiratory rate falls, the restlessness
diminishes, digestive disturbances disappear, tremors decrease,
there is a rapid increase in the body weight, and the patient gradually
resumes his normal state. On the other hand, if for a period
of time extract of the thyroid gland is administered to a normal
individual in excessive dosage, there will develop nervousness,
palpitation of the heart, sweating, loss of weight, slight protrusion
of the eyes, indigestion; in short, most of the phenomena of Graves'
disease and of the strong emotions will be produced artificially
(Figs. 15 and 23). When the administration of the thyroid extract
is discontinued, these phenomena may disappear. On the other hand,
when there is too little or no thyroid gland, the individual
becomes dull, stupid, and emotionless, though he may be irritable;
while if a sufficient amount of thyroid extract be given to such
a patient he may be brought back to his normal condition.
Hence we see that the phenomena of the emotions may within certain
limits be increased, diminished, or abolished by increasing,
diminishing, or totally excluding the secretion of the thyroid gland.
Graves' disease may be increased by giving thyroid extract and by fear.
It may be diminished by removing a part of the gland, or by
interrupting the blood and nerve supply, or by complete rest.
In addition, at some stage of Graves' disease there is an
increase in the size and in the number of the secreting cells.
These facts regarding the normal and the pathologic supply of thyroid
secretion point to this gland as one of the sources of the energizing
substance or substances, by means of which the motor phenomena
of animals are executed and their emotions expressed.
Anger is similar to fear in origin and, like fear, is an integration
and stimulation of the motor mechanism and its accessories.
Animals which have no natural weapons for attack experience neither
fear nor anger, while the animals which have weapons for attack
express anger principally by energizing the muscles used in attack.
Although, as has already been stated, the efficiency of the hands
of man has largely supplanted the use of the teeth, he still shows
his teeth in anger and so gives support to the theory that this
emotion is of remote ancestral origin and proves the great persistence
of phylogenetic association. On this conception we can understand
why it is that a patient consumed by worry--which to me signifies
interrupted stimulation, a state of alternation between hope
and fear--suffers so many bodily impairments and diseases even.
This hypothesis explains the slow dying of animals in captivity.
It explains the grave digestive and metabolic disturbances which
appear under any nerve strain, especially under the strain of fear,
and the great benefits of confidence and hope; it explains the nervousness,
loss of weight, indigestion--in short, the comprehensive physical
changes that are wrought by fear and by sexual love and hate.
On this hypothesis we can understand the physical influence
of one individual over the body and personality of another;
and of the infinite factors in environment that, through phylogenetic
association, play a role in the functions of many of our organs.
It is because under the uncompromising law of survival of the fittest
we were evolved as motor beings that we do not possess any organs or
faculties which have not served our progenitors in accomplishing their
survival in the relentless struggle of organic forms with one another.
We are now, as we were then, essentially motor beings, and the only way in
which we can meet the dangers in our environment is by a motor response.
Such a motor response implies the integration of our entire being
for action, this integration involving the activity of certain glands,
such as the adrenals (Cannon), the thyroid, the liver, etc., which throw
into the blood-stream substances which help to form energy, but which,
if no muscular action ensues, are harmful elements in the blood.
While this motor preparation is going on, the entire digestive
tract is inhibited. It thus becomes clear why an emotion is more
harmful than action.
Any agency that can sufficiently inspire faith,--dispel worry,--
whether that agency be mystical, human, or divine, will at once
stop the body-wide stimulations and inhibitions which cause
lesions which are as truly physical as is a fracture.
The striking benefits of good luck, success, and happiness;
of a change of scene; of hunting and fishing; of optimistic
and helpful friends, are at once explained by this hypothesis.
One can also understand the difference between the broken body
and spirits of an animal in captivity and its buoyant return to its
normal condition when freed.
But time will not permit me to follow this tempting lead, which has
been introduced for another purpose--the proposal of a remedy.
Worries either are or are not groundless. Of those that have
a basis, many are exaggerated. It has occurred to me to utilize
as an antidote an appeal to the same great law that originally
excited the instinctive involuntary reaction known as fear--
the law of self-preservation.
I have found that if an intelligent patient who is suffering from
fear can be made to see so plainly as to become firmly convinced
that his brain, his various organs, indeed his whole being,
could be physically damaged by fear, that this same instinct of
self-preservation will, to the extent of his conviction, banish fear.
It is hurling a threatened active militant danger, whose injurious
influences are both certain and known, against an uncertain,
perhaps a fancied, one. In other words, fear itself is an injury
which when recognized is instinctively avoided. In a similar manner
anger may be softened or banished by an appeal to the stronger
self-preserving instinct aroused by the fear of physical damage,
such as the physical injury of brain-cells. This playing of one
primitive instinct against another is comparable to the effect
produced upon two men who are quarreling when a more powerful enemy
of both comes threateningly on the scene.
The acute fear of a surgical operation may be banished by the use
of certain drugs that depress the associational power of the brain and
so minimize the effect of the preparations that usually inspire fear.
If, in addition, the entire field of operation is blocked by local
anesthesia so that the associational centers are not awakened,
the patient will pass through the operation unscathed.
The phylogenetic origin of fear is injury, hence injury and fear cause
the same phenomena. In their quality and in their phenomena psychic
shock and traumatic shock are the same. The perception of danger
by the special senses in the sound of the opening gun of a battle,
or in the sight of a venomous snake, is phylogenetically the same
and causes the same effects upon the entire body as an operation under
anesthesia or a physical combat in that each drives the motor mechanism.
The use of local anesthetics in the operative field prevents
nerve-currents from the seat of injury from reaching the brain and there
integrating the entire body for a self-defensive struggle. The result,
even though a part of the brain is asleep and the muscles paralyzed,
is the same as that produced by the interception of the terrifying
sound of the gun, or of the sight of the dangerous reptile,
since the stimulation of the motor mechanism is prevented.
By both the positive and the negative evidence we are forced
to believe that the emotions are primitive instinctive reactions
which represent ancestral acts; and that they therefore utilize
the complicated motor mechanism which has been developed by the forces
of evolution as that best adapted to fit the individual for his
struggle with his environment or for procreation.
The mechanism by which the motor acts are performed and the mechanism
by which the emotions are expressed are one and the same.
These acts in their infinite complexity are suggested by association--
phylogenetic association. When our progenitors came in contact
with any exciting element in their environment, action ensued then
and there. There was much action--little restraint or emotion.
Civilized man is really in auto-captivity. He is subjected
to innumerable stimulations, but custom and convention frequently
prevent physical action. When these stimulations are sufficiently
strong but no action ensues, the reaction constitutes an emotion.
A phylogenetic fight is anger; a phylogenetic flight is fear;
a phylogenetic copulation is sexual love, and so one finds in this
conception an underlying principle which may be the key to an
understanding of the emotions and of certain diseases.