differ in the mode of development of their colour-sensibility to this
extent, or can it be that there is some fault in the method of
investigation? It has been recently suggested that the mode of testing
colour-discrimination by naming is open to the objection that a child
may get hold of one verbal sound as "red" more easily than another as
"green" and that this would facilitate the recognition of the former. If
in this way the recognition of a colour is aided by the retention of its
name, we must get rid of this disturbing element of sound. Accordingly
new methods of experiment have been attempted in France and America.
Thus Professor Baldwin investigates the matter by placing two colours
opposite the child's two arms and noting which is reached out to by
right or left arm, which is ignored. He has tabulated the results of a
short series of these simple experiments for testing childish
preference, and supports the conclusions of Binet, as against those of
Preyer, that blue comes in for the first place in the child's
discriminative recognition.[2] It is, however, easy to see that this
method has its own characteristic defects. Thus, to begin with, it
evidently does not directly test colour-discrimination at all, but the
liking for or interest in colours, which though it undoubtedly implies a
measure of discrimination must not be confused with this. And even as a
test of preference it is very likely to be misapplied. Thus supposing
that the two colours are not equally bright, then the child will grasp
at one rather than at the other, because it is a brighter object and not
because it is this particular colour. Again if one colour falls more
into the first and fresh period of the exercise when the child is fresh
and active, whereas another falls more into the second period when he is
tired and inactive, the results would, it is evident, give too much
value to the former. Similarly, if one colour were brought in after
longer intervals of time than another it would have more attractive
force through its greater novelty.
Enough has been said to show how very delicate a problem we have here to
deal with. And if scientific men are still busy settling the point how
the problem can be best dealt with, it seems hopeless for the amateur to
dabble in the matter.
I have purposely chosen a problem of peculiar complexity and delicacy in
order to illustrate the importance of that training which makes the
mental eye of the observer quick to analyse the phenomenon to be dealt
with so as to take in all its conditions. Yet there are many parts of
this work of observing the child's mind which do not make so heavy a
demand on technical ability, but can be done by any intelligent observer
prepared for the task by a reasonable amount of psychological study. I
refer more particularly to that rich and highly interesting field of
exploration which opens up when the child begins to talk. It is in the
spontaneous utterances of children, their first quaint uses of words,
that we can best watch the play of the instinctive tendencies of
thought. Children's talk is always valuable to a psychologist; and for
my part I would be glad of as many anecdotal records of their sayings as
I could collect.
Here, then, there seems to be room for a relatively simple and unskilled
kind of observing work. Yet it would be a mistake to suppose that even
this branch of child-observation requires nothing but ordinary
intelligence. To begin with, we are all prone, till by special training
we have learned to check the inclination, to read far too much of our
older thought and sentiment into children. As M. Drox observes, "we are
the dupes of ourselves when we observe the babe."
Again, there is a subtle source of error connected with the very
attitude of undergoing examination which only a carefully trained
observer of childish ways will avoid. A child is very quick in spying
whether he is being observed, and as soon as he suspects that you are
specially interested in his talk he is apt to try to produce an effect.
This wish to say something startling, wonderful, or what not, will, it
is obvious, detract from the value of the utterance.
But once more the saying which it is so easy to report has had its
history, and the observer who knows something of psychology will look
out for facts, that is to say, experiences of the child, suggestions
made by others' words which throw light on the saying. No fact is
really quite simple, and the reason why some facts look so simple is
that the observer does not include in his view all the connections of
the occurrence which he is inspecting. The unskilled observer of
children is apt to send scraps, fragments of facts, which have not their
natural setting. The value of psychological training is that it makes
one as jealously mindful of wholeness in facts as a housewife of
wholeness in her porcelain. It is, indeed, only when the whole fact is
before us, in well-defined contour, that we can begin to deal with its
meaning. Thus although those ignorant of psychology may assist us in
this region of fact-finding, they can never accomplish that completer
and exacter kind of observation which we dignify by the name of Science.
One may conclude then that women may be fitted to become valuable
labourers in this new field of investigation, if only they will acquire
a genuine scientific interest in babyhood, and a fair amount of
scientific training. That a large number of women will get so far is I
think doubtful: the sentimental or æsthetic attraction of the baby is
apt to be a serious obstacle to a cold matter-of-fact examination of it
as a scientific specimen. The natural delight of a mother in every new
exhibition of infantile wisdom or prowess is liable to blind her to the
exceedingly modest significance of the child's performances as seen from
the scientific point of view. Yet as I have hinted, this very fondness
for infantile ways, may, if only the scientific caution is added, prove
a valuable excitant to study. In England, and in America, there are
already a considerable number of women who have undergone some serious
training in psychology, and it may not be too much to hope that before
long we shall have a band of mothers and aunts busily engaged in noting
and recording the movements of children's minds.
I have assumed here that what is wanted is careful studies of individual
children as they may be approached in the nursery. And these records of
individual children, after the pattern of Preyer's monograph, are I
think our greatest need. We are wont to talk rather too glibly about
that abstraction, "the child," as if all children rigorously
corresponded to one pattern, of which pattern we have a perfect
knowledge. Mothers at least know that this is not so. Children of the
same family will be found to differ very widely (within the
comparatively narrow field of childish traits), as, for example, in
respect of matter-of-factness, of fancifulness, of inquisitiveness.
Thus, while it is probably true that most children at a certain age are
greedy of the pleasures of the imagination, Nature in her well-known
dislike of monotony has taken care to make a few decidedly
unimaginative. We need to know much more about these variations: and
what will best help us here is a number of careful records of infant
progress, embracing examples not only of different sexes and
temperaments, but also of different social conditions and nationalities.
When we have such a collection of monographs we shall be in a much
better position to fill out the hazy outline of our abstract conception
of childhood with definite and characteristic lineaments.
At the same time I gladly allow that other modes of observation are
possible and in their way useful. This applies to older children who
pass into the collective existence of the school-class. Here something
like collective or statistical inquiry may be begun, as that into the
contents of children's minds, their ignorances and misapprehensions
about common objects. Some part of this inquiry into the minds of school
children may very well be undertaken by an intelligent teacher. Thus it
would be valuable to have careful records of children's progress carried
out by pre-arranged tests, so as to get collections of examples of
mental activity at different ages. More special lines of inquiry having
a truly experimental character might be carried out by experts, as those
already begun with reference to children's "span of apprehension,"
_i.e._, the number of digits or nonsense syllables that can be
reproduced after a single hearing, investigations into the effects of
fatigue on mental processes, into the effect of number of repetitions on
the certainty of reproduction, into musical sensitiveness and so forth.
Valuable as such statistical investigation undoubtedly is, it is no
substitute for the careful methodical study of the individual child.
This seems to me the greatest desideratum just now. Since the teacher
needs for practical reasons to make a careful study of individuals he
might well assist here. In these days of literary collaboration it might
not be amiss for a kindergarten teacher to write an account of a child's
mind in co-operation with the mother. Such a record if well done would
be of the greatest value. The co-operation of the mother seems to me
quite indispensable, since even where there is out-of-class intercourse
between teacher and pupil the knowledge acquired by the former never
equals that of the mother.
FOOTNOTES:
[1] The great advantage which the female observer of the infant's mind
has over her male competitor is clearly illustrated in some recent
studies of childhood by American women. I would especially call
attention to a study by Miss M. W. Shinn, (University of California
series) _Notes on the Development of a Child_ (the writer's niece),
where the minute and painstaking record (e.g. of the child's
colour-discrimination and visual space exploration) points to the ample
opportunity of observation which comes more readily to women.
[2] "Mental Development in the Child and the Race," chap. III.
TWINS, THEIR HISTORY AS A CRITERION OF THE RELATIVE POWERS OF NATURE AND
NURTURE
FRANCIS GALTON
[Francis Galton, a cousin of Charles Darwin, has won eminence
by bringing problems of human development to the test of
statistical inquiry. Among his works are "Hereditary Genius,"
"English Men of Science, Their Nature and Nurture," "Human
Faculty," and "Natural Inheritance." The study of Twins here
presented is taken from "Human Faculty," published by
Macmillan & Co., London, 1883.]
The exceedingly close resemblance attributed to twins has been the
subject of many novels and plays, and most persons have felt a desire to
know upon what basis of truth those works of fiction may rest. But twins
have many other claims to attention, one of which will be discussed in
the present memoir. It is, that their history affords means of
distinguishing between the effects of tendencies received at birth, and
of those that were imposed by the circumstances of their after lives; in
other words, between the effects of nature and of nurture. This is a
subject of especial importance in its bearings on investigations into
mental heredity, and I, for my part, have keenly felt the difficulty of
drawing the necessary distinction whenever I tried to estimate the
degree in which mental ability was, on the average, inherited. The
objection to statistical evidence in proof of its inheritance has always
been: "The persons whom you compare may have lived under similar social
conditions and have had similar advantages of education, but such
prominent conditions are only a small part of those that determine the
future of each man's life. It is to trifling accidental circumstances
that the bent of his disposition and his success are mainly due, and
these you leave wholly out of account--in fact, they do not admit of
being tabulated, and therefore your statistics, however plausible at
first sight, are really of very little use." No method of enquiry which
I have been able to carry out--and I have tried many methods--is wholly
free from this objection. I have therefore attacked the problem from the
opposite side, seeking for some new method by which it would be possible
to weigh in just scales the respective effects of nature and nurture,
and to ascertain their several shares in framing the disposition and
intellectual ability of men. The life history of twins supplies what I
wanted. We might begin by enquiring about twins who were closely alike
in boyhood and youth, and who were educated together for many years, and
learn whether they subsequently grew unlike, and, if so, what the main
causes were which, in the opinion of the family, produced the
dissimilarity. In this way we may obtain much direct evidence of the
kind we want; but we can also obtain yet more valuable evidence by a
converse method. We can enquire into the history of twins who were
exceedingly unlike in childhood, and learn how far they became
assimilated under the influence of their identical nurtures; having the
same home, the same teachers, the same associates, and in every other
respect the same surroundings.
My materials were obtained by sending circulars of enquiry to persons
who were either twins themselves or the near relations of twins. The
printed questions were in thirteen groups; the last of them asked for
the addresses of other twins known to the recipient who might be likely
to respond if I wrote to them. This happily led to a continually
widening circle of correspondence, which I pursued until enough material
was accumulated for a general reconnaissance of the subject.
The reader will easily understand that the word "twins" is a vague
expression, which covers two very dissimilar events; the one
corresponding to the progeny of animals that have usually more than one
young one at a birth, and the other corresponding to those double-yolked
eggs that are due to two germinal spots in a single ovum. The
consequence of this is, that I find a curious discontinuity in my
results. One would have expected that twins would commonly be found to
possess a certain average likeness to one another; that a few would
greatly exceed that degree of likeness, and a few would greatly fall
short of it; but this is not at all the case. Twins may be divided into
three groups, so distinct that there are not many intermediate
instances; namely, strongly alike, moderately alike, and extremely
dissimilar. When the twins are a boy and a girl, they are never closely
alike; in fact, their origin never corresponds to that of the
above-mentioned double-yolked eggs.
I have received about eighty returns of cases of close similarity,
thirty-five of which entered into many instructive details. In a few of
these not a single point of difference could be specified. In the
remainder, the colour of the hair and eyes were almost always identical;
the height, weight, and strength were generally very nearly so, but I
have a few cases of a notable difference in these, notwithstanding the
resemblance was otherwise very near. The manner and address of the
thirty-five pairs of twins is usually described as being very similar,
though there often exists a difference of expression familiar to near
relatives but unperceived by strangers. The intonation of the voice when
speaking is commonly the same, but it frequently happens that the twins
sing in different keys. Most singularly, that one point in which
similarity is rare is the handwriting. I cannot account for this,
considering how strongly handwriting runs in families, but I am sure of
the fact. I have only one case in which nobody, not even the twins
themselves, could distinguish their own notes of lectures, etc.; barely
two or three in which the handwriting was undistinguishable by others,
and only a few in which it was described as closely alike. On the other
hand, I have many in which it is stated to be unlike, and some in which
it is alluded to as the only point of difference.
One of my enquiries was for anecdotes as regards the mistakes made by
near relatives between the twins. They are numerous, but not very varied
in character. When the twins are children, they have commonly to be
distinguished by ribbons tied round their wrist or neck; nevertheless
the one is sometimes fed, physicked, and whipped by mistake for the
other, and the description of these little domestic catastrophes is
usually given to me by the mother, in a phraseology that is somewhat
touching by reason of its seriousness. I have one case in which a doubt
remains whether the children were not changed in their bath, and the
presumed A is not really B, and _vice versa_. In another case an artist
was engaged on the portraits of twins who were between three and four
years of age; he had to lay aside his work for three weeks, and, on
resuming it, could not tell to which child the respective likenesses he
had in hand belonged. The mistakes are less numerous on the part of the
mother during the boyhood and girlhood of the twins, but almost as
frequent on the part of strangers. I have many instances of tutors being
unable to distinguish their twin pupils. Thus, two girls used regularly
to impose on their music teacher when one of them wanted a whole
holiday; they had their lessons at separate hours, and the one girl
sacrificed herself to receive two lessons on the same day, while the
other one enjoyed herself. Here is a brief and comprehensive account:
"Exactly alike in all, their schoolmasters never could tell them apart;
at dancing parties they constantly changed partners without discovery;
their close resemblance is scarcely diminished by age." The following is
a typical schoolboy anecdote: Two twins were fond of playing tricks, and
complaints were frequently made; but the boys would never own which was
the guilty one, and the complainants were never certain which of the two
he was. One head master used to say he would never flog the innocent for
the guilty, and another used to flog both. No less than nine anecdotes
have reached me of a twin seeing his or her reflection in a
looking-glass, and addressing it, in the belief it was the other twin in
person. I have many anecdotes of mistakes when the twins were nearly
grown up. Thus: "Amusing scenes occurred at college when one twin came
to visit the other; the porter on one occasion refused to let the
visitor out of the college gates, for, though they stood side by side,
he professed ignorance as to which he ought to allow to depart."
Children are usually quick in distinguishing between their parents and
his or her twin: but I have two cases to the contrary. Thus, the
daughter of a twin says: "Such was the marvellous similarity of their
features, voice, manner, etc. that I remember, as a child, being very
much puzzled, and I think, had my aunt lived much with us, I should have
ended by thinking I had two mothers." The other, a father of twins,
remarks: "We were extremely alike, and are so at this moment, so much so
that our children up to five and six years old did not know us apart."
I have four or five instances of doubt during an engagement of marriage.
Thus: "A married first, but both twins met the lady together for the
first time, and fell in love with her there and then. A managed to see
her home and to gain her affection, though B went sometimes courting in
his place, and neither the lady nor her parents could tell which was
which." I have also a German letter, written in quaint terms, about twin
brothers who married sisters, but could not easily be distinguished by
them. In the well-known novel by Mr. Wilkie Collins of "Poor Miss
Finch," the blind girl distinguishes the twin she loves by the touch of
his hand, which gives her a thrill that the touch of the other brother
does not. Philosophers have not, I believe, as yet investigated the
conditions of such thrills; but I have a case in which Miss Finch's test
would have failed. Two persons, both friends of a certain twin lady,
told me that she had frequently remarked to them that "kissing her twin
sister was not like kissing her other sisters, but like kissing
herself--her own hand, for example."
It would be an interesting experiment for twins who were closely alike,
to try how far dogs could distinguish between them by scent.
I have a few anecdotes of strange mistakes made between twins in adult
life. Thus, an officer writes: "On one occasion when I returned from
foreign service my father turned to me and said, 'I thought you were in
London,' thinking I was my brother--yet he had not seen me for nearly
four years--our resemblance was so great."
The next and last anecdote I shall give is, perhaps, the most remarkable
of those that I have: it was sent me by the brother of the twins, who
were in middle life at the time of its occurrence: "A was again coming
home from India, on leave; the ship did not arrive for some days after
it was due; the twin brother B had come up from his quarters to receive
A, and their old mother was very nervous. One morning A rushed in,
saying, 'Oh, mother, how are you?' Her answer was, 'No, B, it's a bad
joke; you know how anxious I am!' and it was a little time before A
could persuade her that he was the real man."
Enough has been said to prove that an extremely close personal
resemblance frequently exists between twins of the same sex; and that,
although the resemblance usually diminishes as they grow into manhood
and womanhood, some cases occur in which the resemblance is lessened in
a hardly perceptible degree. It must be borne in mind that the
divergence of development, when it occurs, need not be ascribed to the
effect of different nurtures, but that it is quite possible that it may
be due to the appearance of qualities inherited at birth, though
dormant, like gout, in early life. To this I shall recur.
There is a curious feature in the character of the resemblance between
twins, which has been alluded to by a few correspondents: it is well
illustrated by the following quotations. A mother of twins says: "There
seems to be a sort of interchangeable likeness in expression, that often
gave to each the affect of being more like his brother than himself."
Again, two twin brothers, writing to me, after analysing their points of
resemblance, which are close and numerous, and pointing out certain
shades of difference, add: "These seem to have marked us through life,
though for a while when we were first separated, the one to go to
business, and the other to college, our respective characters were
inverted; we both think that at that time we each ran into the character
of the other. The proof of this consists in our own recollections, in
our correspondence by letter, and in the views which we then took of
matters in which we were interested." In explanation of this apparent
interchangeableness, we must recollect that no character is simple, and
that in twins who strongly resemble each other every expression in the
one may be matched by a corresponding expression in the other, but it
does not follow that the same expression should be the dominant one in
both cases. Now it is by their dominant expressions that we should
distinguish between the twins; consequently when one twin has
temporarily the expression which is the dominant one in his brother, he
is apt to be mistaken for him. There are also cases where the
development of the two twins is not strictly by equal steps; they reach
the same goal at the same time, but not by identical stages. Thus: A is
born the larger, then B overtakes and surpasses A, the end being that
the twins become closely alike. This process would aid in giving an
interchangeable likeness at certain periods of their growth, and is
undoubtedly due to nature more frequently than to nurture.
Among my thirty-five detailed cases of close similarity, there are no
less than seven in which both twins suffered from some special ailment
or had some exceptional peculiarity. One twin writes that she and her
sister "have both the defect of not being able to come down stairs
quickly, which, however, was not born with them, but came on at the age
of twenty." Another pair of twins have a slight congenital flexure of
one of the joints of the little finger: it was inherited from a
grandmother, but neither parents, nor brothers, nor sisters show the
least trace of it. In another case, one was born ruptured, and the other
became so at six months old. Two twins at the age of twenty-three were
attacked by toothache, and the same tooth had to be extracted in each
case. There are curious and close correspondences mentioned in the
falling off of the hair. Two cases are mentioned of death from the same
disease; one of which is very affecting. The outline of the story was
that the twins were closely alike and singularly attached, and had
identical tastes; they both obtained Government clerkships, and kept
house together, when one sickened and died of Bright's disease, and the
other also sickened of the same disease and died seven months later.
In no less than nine out of the thirty-five cases does it appear that
both twins are apt to sicken at the same time. This implies so intimate
a constitutional resemblance, that it is proper to give some quotations
in evidence. Thus, the father of two twins says: "Their general health
is closely alike; whenever one of them has an illness the other
invariably has the same within a day or two, and they usually recover in
the same order. Such has been the case with whooping cough, chicken-pox,
and measles; also with slight bilious attacks, which they have
successively. Latterly, they had a feverish attack at the same time."
Another parent of twins says: "If anything ails one of them, identical
symptoms _nearly always_ appear in the other: this has been singularly
visible in two instances during the last two months. Thus, when in
London, one fell ill with a violent attack of dysentery, and within
twenty-four hours the other had precisely the same symptoms."