inference securely based thereon to distinguish what is primary from
what is in part due to secondary acquisition--a fact which Darwin
fully appreciated. Animals are educable in different degrees; but
where they are educable they begin to profit by experience from the
first. Only, therefore, on the occasion of the first instinctive act
of a given type can the experience gained be regarded as _wholly_
primary; all subsequent performance is liable to be in some degree,
sometimes more, sometimes less, modified by the acquired disposition
which the initial behaviour engenders. But the early stages of
acquisition are always along the lines predetermined by instinctive
differentiation. It is the task of comparative psychology to
distinguish the primary tissue of experience from its secondary and
acquired modifications. We cannot follow up the matter in further
detail. It must here suffice to suggest that this conception of
instinct as a primary form of experience lends itself better to
natural history treatment than Darwin's conception of an impelling
force, and that it is in line with the main trend of Darwin's thought.
In a characteristic work,--characteristic in wealth of detail, in
closeness and fidelity of observation, in breadth of outlook, in
candour and modesty,--Darwin dealt with _The Expression of the
Emotions in Man and Animals_. Sir Charles Bell in his _Anatomy of
Expression_ had contended that many of man's facial muscles had been
specially created for the sole purpose of being instrumental in the
expression of his emotions. Darwin claimed that a natural explanation,
consistent with the doctrine of evolution, could in many cases be
given and would in other cases be afforded by an extension of the
principles he advocated. "No doubt," he said,[167] "as long as man and
all other animals are viewed as independent creations, an effectual
stop is put to our natural desire to investigate as far as possible
the causes of Expression. By this doctrine, anything and everything
can be equally well explained.... With mankind, some expressions ...
can hardly be understood, except on the belief that man once existed
in a much lower and animal-like condition. The community of certain
expressions in distinct though allied species ... is rendered somewhat
more intelligible, if we believe in their descent from a common
progenitor. He who admits on general grounds that the structure and
habits of all animals have been gradually evolved, will look at the
whole subject of Expression in a new and interesting light."
Darwin relied on three principles of explanation. "The first of these
principles is, that movements which are serviceable in gratifying some
desire, or in relieving some sensation, if often repeated, become so
habitual that they are performed, whether or not of any service,
whenever the same desire or sensation is felt, even in a very weak
degree."[168] The modes of expression which fall under this head have
become instinctive through the hereditary transmission of acquired
habit. "As far as we can judge, only a few expressive movements are
learnt by each individual; that is, were consciously and voluntarily
performed during the early years of life for some definite object, or
in imitation of others, and then became habitual. The far greater
number of the movements of expression, and all the more important
ones, are innate or inherited; and such cannot be said to depend on
the will of the individual. Nevertheless, all those included under our
first principle were at first voluntarily performed for a definite
object,--namely, to escape some danger, to relieve some distress, or
to gratify some desire."[169]
"Our second principle is that of antithesis. The habit of voluntarily
performing opposite movements under opposite impulses has become
firmly established in us by the practice of our whole lives. Hence, if
certain actions have been regularly performed, in accordance with our
first principle, under a certain frame of mind, there will be a strong
and involuntary tendency to the performance of directly opposite
actions, whether or not these are of any use, under the excitement of
an opposite frame of mind."[170] This principle of antithesis has not
been widely accepted. Nor is Darwin's own position easy to grasp.
"Our third principle," he says,[171] "is the direct action of the
excited nervous system on the body, independently of the will, and
independently, in large part, of habit. Experience shows that
nerve-force is generated and set free whenever the cerebro-spinal
system is excited. The direction which this nerve-force follows is
necessarily determined by the lines of connection between the
nerve-cells, with each other and with various parts of the body."
Lack of space prevents our following up the details of Darwin's
treatment of expression. Whether we accept or do not accept his three
principles of explanation we must regard his work as a masterpiece of
descriptive analysis, packed full of observations possessing lasting
value. For a further development of the subject it is essential that
the instinctive factors in expression should be more fully
distinguished from those which are individually acquired--a difficult
task--and that the instinctive factors should be rediscussed in the
light of modern doctrines of heredity, with a view to determining
whether Lamarckian inheritance, on which Darwin so largely relied, is
necessary for an interpretation of the facts.
The whole subject as Darwin realised is very complex. Even the term
"expression" has a certain amount of ambiguity. When the emotion is in
full flood, the animal fights, flees, or faints. Is this full-tide
effect to be regarded as expression; or are we to restrict the term to
the premonitory or residual effects--the bared canine when the
fighting mood is being roused, the ruffled fur when reminiscent
representations of the object inducing anger cross the mind? Broadly
considered both should be included. The activity of premonitory
expression as a means of communication was recognised by Darwin; he
might, perhaps, have emphasised it more strongly in dealing with the
lower animals. Man so largely relies on a special means of
communication, that of language, that he sometimes fails to realise
that for animals with their keen powers of perception, and dependent
as they are on such means of communication, the more strictly
biological means of expression are full of subtle suggestiveness. Many
modes of expression, otherwise useless, are signs of behaviour that
may be anticipated,--signs which stimulate the appropriate attitude of
response. This would not, however, serve to account for the utility of
the organic accompaniments--heart-affection, respiratory changes,
vaso-motor effects and so forth, together with heightened muscular
tone,--on all of which Darwin lays stress[172] under his third
principle. The biological value of all this is, however, of great
importance, though Darwin was hardly in a position to take it fully
into account.
Having regard to the instinctive and hereditary factors of emotional
expression we may ask whether Darwin's third principle does not alone
suffice as an explanation. Whether we admit or reject Lamarckian
inheritance it would appear that all hereditary expression must be due
to pre-established connections within the central nervous system and
to a transmitted provision for coordinated response under the
appropriate stimulation. If this be so, Darwin's first and second
principles are subordinate and ancillary to the third, an expression,
so far as it is instinctive or heredity, being "the direct result of
the constitution of the nervous system."
Darwin accepted the emotions themselves as hereditary or acquired
states of mind and devoted his attention to their expression. But
these emotions themselves are genetic products and as such dependent
on organic conditions. It remained, therefore, for psychologists who
accepted evolution and sought to build on biological foundations to
trace the genesis of these modes of animal and human experience. The
subject has been independently developed by Professors Lange and
James;[173] and some modification of their view is regarded by many
evolutionists as affording the best explanation of the facts. We must
fix our attention on the lower emotions, such as anger or fear, and on
their first occurrence in the life of the individual organism. It is a
matter of observation that if a group of young birds which have been
hatched in an incubator are frightened by an appropriate presentation,
auditory or visual, they instinctively respond in special ways. If we
speak of this response as the expression, we find that there are many
factors. There are certain visible modes of behaviour, crouching at
once, scattering and then crouching, remaining motionless, the braced
muscles sustaining an attitude of arrest, and so forth, There are also
certain visceral or organic effects, such as affections of the heart
and respiration. These can be readily observed by taking the young
bird in the hand. Other effects cannot be readily observed; vaso-motor
changes, affections of the alimentary canal, the skin and so forth.
Now the essence of the James-Lange view, as applied to these
congenital effects, is that though we are justified in speaking of
them as effects of the stimulation, we are not justified, without
further evidence, in speaking of them as effects of the emotional
state. May it not rather be that the emotion as a primary mode of
experience is the concomitant of the net result of the organic
situation--the initial presentation, the instinctive mode of
behaviour, the visceral disturbances?
According to this interpretation the primary tissue of experience of
the emotional order, felt as an unanalysed complex, is generated by
the stimulation of the sensorium by afferent or incoming physiological
impulses from the special senses, from the organs concerned in the
responsive behaviour, from the viscere and vaso-motor system.
Some psychologists, however, contend that the emotional experience is
generated in the sensorium prior to, and not subsequent to, the
behaviour-response and the visceral disturbances. It is a direct and
not an indirect outcome of the presentation to the special senses. Be
this as it may, there is a growing tendency to bring into the closest
possible relation, or even to identify, instinct and emotion in their
primary genesis. The central core of all such interpretations is that
instinctive behaviour and experience, its emotional accompaniments,
and its expression, are but different aspects of the outcome of the
same organic occurrences. Such emotions are, therefore, only a
distinguishable aspect of the primary tissue of experience and exhibit
a like differentiation. Here again a biological foundation is laid for
a psychological doctrine of the mental development of the individual.
The intimate relation between emotion as a psychological mode of
experience and expression as a group of organic conditions has an
important bearing on biological interpretation. The emotion, as the
psychological accompaniment of orderly disturbances in the central
nervous system, profoundly influences behaviour and often renders it
more vigourous and more effective. The utility of the emotions in the
struggle for existence can, therefore, scarcely be over-estimated.
Just as keenness of perception has survival-value; just as it is
obviously subject to variation; just as it must be enhanced under
natural selection, whether individually acquired increments are
inherited or not; and just as its value lies not only in this or that
special perceptive act but in its importance for life as a whole; so
the vigourous effectiveness of activity has survival-value; it is
subject to variation; it must be enhanced under natural selection; and
its importance lies not only in particular modes of behaviour but in
its value for life as a whole. If emotion and its expression as a
congenital endowment are but different aspects of the same biological
occurrence; and if this is a powerful supplement to vigour
effectiveness and persistency of behaviour, it must on Darwin's
principles be subject to natural selection.
If we include under the expression of the emotions not only the
premonitory symptoms of the initial phases of the organic and mental
state, not only the signs or conditions of half-tide emotion, but the
full-tide manifestation of an emotion which dominates the situation,
we are naturally led on to the consideration of many of the phenomena
which are discussed under the head of sexual selection. The subject is
difficult and complex, and it was treated by Darwin with all the
strength he could summon to the task. It can only be dealt with here
from a special point of view--that which may serve to illustrate the
influence of certain mental factors on the course of evolution. From
this point of view too much stress can scarcely be laid on the
dominance of emotion during the period of courtship and pairing in the
more highly organised animals. It is a period of maximum vigour,
maximum activity, and, correlated with special modes of behaviour and
special organic and visceral accompaniments, a period also of maximum
emotional excitement. The combats of males, their dances and aerial
evolutions, their elaborate behaviour and display, or the flood of
song in birds, are emotional expressions which are at any rate
coincident in time with sexual periodicity. From the combat of the
males there follows on Darwin's principles the elimination of those
which are deficient in bodily vigour, deficient in special structures,
offensive or protective, which contribute to success, deficient in the
emotional supplement of which persistent and whole-hearted fighting is
the expression, and deficient in alertness and skill which are the
outcome of the psychological development of the powers of perception.
Few biologists question that we have here a mode of selection of much
importance, though its influence on psychological evolution often
fails to receive its due emphasis. Mr. Wallace[174] regards it as "a
form of natural selection"; "to it," he says, "we must impute the
development of the exceptional strength, size, and activity of the
male, together with the possession of special offensive and defensive
weapons, and of all other characters which arise from the development
of these or are correlated with them." So far there is little
disagreement among the followers of Darwin--for Mr. Wallace, with fine
magnanimity, has always preferred to be ranked as such,
notwithstanding his right, on which a smaller man would have
constantly insisted, to the claim of independent originator of the
doctrine of natural selection. So far with regard to sexual selection
Darwin and Mr. Wallace are agreed; so far and no farther. For Darwin,
says Mr. Wallace,[175] "has extended the principle into a totally
different field of action, which has none of that character of
constancy and of inevitable result that attaches to natural selection,
including male rivalry; for by far the larger portion of the
phenomena, which he endeavours to explain by the direct action of
sexual selection, can only be so explained on the hypothesis that the
immediate agency is female choice or preference. It is to this that he
imputes the origin of all secondary sexual characters other than
weapons of offence and defence.... In this extension of sexual
selection to include the action of female choice or preference, and in
the attempt to give to that choice such wide-reaching effects, I am
unable to follow him more than a very little way."
Into the details of Mr. Wallace's criticisms it is impossible to enter
here. We cannot discuss either the mode of origin of the variations in
structure which have rendered secondary sexual characters possible or
the modes of selection other than sexual which have rendered them,
within narrow limits, specifically constant. Mendelism and mutation
theories may have something to say on the subject when these theories
have been more fully correlated with the basal principles of
selection. It is noteworthy that Mr. Wallace says:[176] "Besides the
acquisition of weapons by the male for the purpose of fighting with
other males, there are some other sexual characters which may have
been produced by natural selection. Such are the various sounds and
odours which are peculiar to the male, and which serve as a call to
the female or as an indication of his presence. These are evidently a
valuable addition to the means of recognition of the two sexes, and
are a further indication, that the pairing season has arrived; and the
production, intensification, and differentiation of these sounds and
odours are clearly within the power of natural selection. The same
remark will apply to the peculiar calls of birds, and even to the
singing of the males." Why the same remark should not apply to their
colours and adornments is not obvious. What is obvious is that "means
of recognition" and "indication that the pairing season has arrived"
are dependent on the perceptive powers of the female who recognises
and for whom the indication has meaning. The hypothesis of female
preference, stripped of the aesthetic surplusage which is
psychologically both unnecessary and unproven, is really only
different in degree from that which Mr. Wallace admits in principle
when he says that it is probable that the female is pleased or excited
by the display.
Let us for our present purpose leave on one side and regard as _sub
judice_ the question whether the specific details of secondary sexual
characters are the outcome of female choice. For us the question is
whether certain psychological accompaniments of the pairing situation
have influenced the course of evolution and whether these
psychological accompaniments are themselves the outcome of evolution.
As a matter of observation, specially differentiated modes of
behaviour, often very elaborate, frequently requiring highly developed
skill, and apparently highly charged with emotional tone, are the
precursors of pairing. They are generally confined to the males, whose
fierce combats during the period of sexual activity are part of the
emotional manifestation. It is inconceivable that they have no
biological meaning; and it is difficult to conceive that they have any
other biological end than to evoke in the generally more passive
female the pairing impulse. They, are based on instinctive foundations
ingrained in the nervous constitution through natural (or may we not
say sexual?) selection in virtue of their profound utility. They are
called into play by a specialised presentation such as the sight or
the scent of the female at, or a little in advance of, a critical
period of the physiological rhythm. There is no necessity that the
male should have any knowledge of the end to which his strenuous
activity leads up. In presence of the female there is an elaborate
application of all the energies of behaviour, just because ages of
racial preparation have made him biologically and emotionally what he
is--a functionally sexual male that must dance or sing or go through
hereditary movements of display, when the appropriate stimulation
comes. Of course after the first successful courtship his future
behaviour will be in some degree modified by his previous experience.
No doubt during his first courtship he is gaining the primary data of
a peculiarly rich experience, instinctive and emotional. But the
biological foundations of the behaviour of courtship are laid in the
hereditary coordinations. It would seem that in some cases, not indeed
in all, perhaps especially in those cases in which secondary sexual
behaviour is most highly evolved,--correlative with the ardour of the
male is a certain amount of reluctance in the female. The pairing act
on her part only takes place after prolonged stimulation, for
affording which the behaviour of male courtship is the requisite
presentation. The most vigourous, defiant and mettlesome male is
preferred just because he alone affords a contributory stimulation
adequate to evoke the pairing impulse with its attendant emotional
tone.
It is true that this places female preference or choice on a much
lower psychological plane than Darwin in some passages seems to
contemplate where, for example, he says that the female appreciates
the display of the male and places to her credit a taste for the
beautiful. But Darwin himself distinctly states[177] that "it is not
probable that she consciously deliberates; but she is most excited or
attracted by the most beautiful, or melodious, or gallant males." The
view here put forward, which has been developed by Prof. Groos,[178]
therefore seems to have Darwin's own sanction. The phenomena are not
only biological; there are psychological elements as well. One can
hardly suppose that the female is unconscious of the male's presence;
the final yielding must surely be accompanied by heightened emotional
tone. Whether we call it choice or not is merely a matter of
definition of terms. The behaviour is in part determined by
supplementary psychological values. Prof. Groos regards the coyness of
females as "a most efficient means of preventing the too early and too
frequent yielding to the sexual impulse."[179] Be that as it may, it
is, in any case, if we grant the facts, a means through which male
sexual behaviour with all its biological and psychological
implications, is raised to a level otherwise perhaps unattainable by
natural means, while in the female it affords opportunities for the
development in the individual and evolution in the race of what we may
follow Darwin in calling appreciation, if we empty this word of the
aesthetic implications which have gathered round it in the mental life
of man.
Regarded from this standpoint of sexual selection, broadly considered,
has probably been of great importance. The psychological
accompaniments of the pairing situation have profoundly influenced the
course of biological evolution and are themselves the outcome of that
evolution.
Darwin makes only passing reference to those modes of behaviour in
animals which go by the name of play. "Nothing," he says,[180] "is
more common than for animals to take pleasure in practising whatever
instinct they follow at other times for some real good." This is one
of the very numerous cases in which a hint of the master has served to
stimulate research in his disciples. It was left to Prof. Groos to
develop this subject on evolutionary lines and to elaborate in a
masterly manner Darwin's suggestion. "The utility of play," he
says,[181] "is incalculable. This utility consists in the practice and
exercise it affords for some of the more important duties of
life,"--that is to say, for the performance of activities which will
in adult life be essential to survival. He urges[182] that "the play
of young animals has its origin in the fact that certain very
important instincts appear at a time when the animal does not
seriously need them." It is, however, questionable whether any
instincts appear at a time when they are not needed. And it is
questionable whether the instinctive and emotional attitude of the
play-fight, to take one example, can be identified with those which
accompany fighting in earnest, though no doubt they are closely
related and have some common factors. It is probable that play, as
preparatory behaviour, differs in biological detail (as it almost
certainly does in emotional attributes) from the earnest of after-life
and that it has been evolved through differentiation and integration
of the primary tissue of experience, as a preparation through which
certain essential modes of skill may be acquired--those animals in
which the preparatory play-propensity was not inherited in due force
and requisite amount being subsequently eliminated in the struggle for
existence. In any case there is little question that Prof. Groos is
right in basing the play-propensity on instinctive foundations.[183]
None the less, as he contends, the essential biological value of play
is that it is a means of training the educable nerve-tissue, of
developing that part of the brain which is modified by experience and
which thus acquires new characters, of elaborating the secondary
tissue of experience on the predetermined lines of instinctive
differentiation and thus furthering the psychological activities which
are included under the comprehensive term "intelligent."