extremely close resemblance between certain twins is the similarity
in the association of their ideas. No less than eleven out of the
thirty-five cases testify to this. They make the same remarks on the
same occasion, begin singing the same song at the same moment, and
so on; or one would commence a sentence, and the other would finish
it. An observant friend graphically described to me the effect
produced on her by two such twins whom she had met casually. She said:
"Their teeth grew alike, they spoke alike and together, and said the
same things, and seemed just like one person." One of the most
curious anecdotes that I have received concerning this similarity of
ideas was that one twin, A, who happened to be at a town in Scotland,
bought a set of champagne glasses which caught his attention, as a
surprise for his brother B; while, at the same time, B, being in
England, bought a similar set of precisely the same pattern as a
surprise for A. Other anecdotes of a like kind have reached me about
these twins.
The last point to which I shall allude regards the tastes and
dispositions of the thirty-five pairs of twins. In sixteen
cases--that is, in nearly one-half of them--these were described as
closely similar; in the remaining nineteen they were much alike, but
subject to certain named differences. These differences belonged
almost wholly to such groups of qualities as these: The one was the
more vigorous, fearless, energetic; the other was gentle, clinging,
and timid; or the one was more ardent, the other more calm and placid;
or again, the one was the more independent, original, and
self-contained; the other the more generous, hasty, and vivacious.
In short, the difference was that of intensity or energy in one or
other of its protean forms; it did not extend more deeply into the
structure of the characters. The more vivacious might be subdued by
ill health, until he assumed the character of the other; or the
latter might be raised by excellent health to that of the former.
The difference was in the key-note, not in the melody.
It follows from what has been said concerning the similar
dispositions of the twins, the similarity in the associations of
their ideas, of their special ailments, and of their illnesses
generally, that the resemblances are not superficial, but extremely
intimate. I have only two cases of a strong bodily resemblance being
accompanied by mental diversity, and one case only of the converse
kind. It must be remembered that the conditions which govern extreme
likeness between twins are not the same as those between ordinary
brothers and sisters, and that it would be incorrect to conclude
from what has just been said about the twins that mental and bodily
likeness are invariably co-ordinate, such being by no means the case.
We are now in a position to understand that the phrase "close
similarity" is no exaggeration, and to realise the value of the
evidence I am about to adduce. Here are thirty-five cases of twins
who were "closely alike" in body and mind when they were young, and
who have been reared exactly alike up to their early manhood and
womanhood. Since then the conditions of their lives have changed;
what change of Nurture has produced the most variation?
It was with no little interest that I searched the records of the
thirty-five cases for an answer; and they gave an answer that was
not altogether direct, but it was distinct, and not at all what I
had expected. They showed me that in some cases the resemblance of
body and mind had continued unaltered up to old age, notwithstanding
very different conditions of life; and they showed in the other
cases that the parents ascribed such dissimilarity as there was,
wholly or almost wholly to some form of illness. In four cases it
was scarlet fever; in a fifth, typhus; in a sixth, a slight effect
was ascribed to a nervous fever; in a seventh it was the effect of
an Indian climate; in an eighth, an illness (unnamed) of nine
months' duration; in a ninth, varicose veins; in a tenth, a bad
fracture of the leg, which prevented all active exercise afterwards;
and there were three additional instances of undefined forms of ill
health. It will be sufficient to quote one of the returns; in this
the father writes:
"At birth they were _exactly_ alike, except that one was born with a
bad varicose affection, the effect of which had been to prevent any
violent exercise, such as dancing or running, and, as she has grown
older, to make her more serious and thoughtful. Had it not been for
this infirmity, I think the two would have been as exactly alike as
it is possible for two women to be, both mentally and physically;
even now they are constantly mistaken for one another."
In only a very few cases is some allusion made to the dissimilarity
being partly due to the combined action of many small influences,
and in none of the thirty-five cases is it largely, much less wholly,
ascribed to that cause. In not a single instance have I met with a
word about the growing dissimilarity being due to the action of the
firm free-will of one or both of the twins, which had triumphed over
natural tendencies; and yet a large proportion of my correspondents
happen to be clergymen, whose bent of mind is opposed, as I feel
assured from the tone of their letters, to a necessitarian view of
life.
It has been remarked that a growing diversity between twins may be
ascribed to the tardy development of naturally diverse qualities;
but we have a right, upon the evidence I have received, to go
farther than this. We have seen that a few twins retain their close
resemblance through life; in other words, instances do exist of an
apparently thorough similarity of nature, in which such difference
of external circumstances as may be consistent with the ordinary
conditions of the same social rank and country do not create
dissimilarity. Positive evidence, such as this, cannot be outweighed
by any amount of negative evidence. Therefore, in those cases where
there is a growing diversity, and where no external cause can be
assigned either by the twins themselves or by their family for it,
we may feel sure that it must be chiefly or altogether due to a want
of thorough similarity in their nature. Nay, further, in some cases
it is distinctly affirmed that the growing dissimilarity can be
accounted for in no other way. We may, therefore, broadly conclude
that the only circumstance, within the range of those by which
persons of similar conditions of life are affected, that is capable
of producing a marked effect on the character of adults, is illness
or some accident which causes physical infirmity. The twins who
closely resembled each other in childhood and early youth, and were
reared under not very dissimilar conditions, either grow unlike
through the development of natural characteristics which had lain
dormant at first, or else they continue their lives, keeping time
like two watches, hardly to be thrown out of accord except by some
physical jar. Nature is far stronger than Nurture within the limited
range that I have been careful to assign to the latter.
The effect of illness, as shown by these replies, is great, and well
deserves further consideration. It appears that the constitution of
youth is not so elastic as we are apt to think, but that an attack,
say of scarlet fever, leaves a permanent mark, easily to be measured
by the present method of comparison. This recalls an impression made
strongly on my mind several years ago, by the sight of some curves
drawn by a mathematical friend. He took monthly measurements of the
circumference of his children's heads during the first few years of
their lives, and he laid down the successive measurements on the
successive lines of a piece of ruled paper, by taking the edge of
the paper as a base. He then joined the free ends of the lines, and
so obtained a curve of growth. These curves had, on the whole, that
regularity of sweep that might have been expected, but each of them
showed occasional halts, like the landing-places on a long flight of
stairs. The development had been arrested by something, and was not
made up for by after growth. Now, on the same piece of paper my
friend had also registered the various infantile illnesses of the
children, and corresponding to each illness was one of these halts.
There remained no doubt in my mind that, if these illnesses had been
warded off, the development of the children would have been
increased by almost the precise amount lost in these halts. In other
words, the disease had drawn largely upon the capital, and not only
on the income, of their constitutions. I hope these remarks may
induce some men of science to repeat similar experiments on their
children of the future. They may compress two years of a child's
history on one side of a ruled half-sheet of foolscap paper, if they
cause each successive line to stand for a successive month,
beginning from the birth of the child; and if they economise space
by laying, not the 0-inch division of the tape against the edge of
the pages, but, say, the 10-inch division.
The steady and pitiless march of the hidden weaknesses in our
constitutions, through illness to death, is painfully revealed by
these histories of twins. We are too apt to look upon illness and
death as capricious events, and there are some who ascribe them to
the direct effect of supernatural interference, whereas the fact of
the maladies of two twins being continually alike shows that illness
and death are necessary incidents in a regular sequence of
constitutional changes beginning at birth, and upon which external
circumstances have, on the whole, very small effect. In cases where
the maladies of the twins are continually alike, the clocks of their
two lives move regularly on at the same rate, governed by their
internal mechanism. When the hands approach the hour, there are
sudden clicks, followed by a whirring of wheels; the moment that
they touch it, the strokes fall. Necessitarians may derive new
arguments from the life-histories of twins.
We will now consider the converse side of our subject, which appears
to me even the more important of the two. Hitherto we have
investigated cases where the similarity at first was close, but
afterwards became less; now we will examine those in which there was
great dissimilarity at first, and will see how far an identity of
nurture in childhood and youth tended to assimilate them. As has
been already mentioned, there is a large proportion of cases of
sharply-contrasted characteristics, both of body and mind, among
twins. I have twenty such cases, given with much detail. It is a
fact that extreme dissimilarity, such as existed between Esau and
Jacob, is a no less marked peculiarity in twins of the same sex than
extreme similarity. On this curious point, and on much else in the
history of twins, I have many remarks to make, but this is not the
place to make them.
The evidence given by the twenty cases above mentioned is absolutely
accordant, so that the character of the whole may be exactly
conveyed by a few quotations.
(1.) One parent says:--"They have had _exactly the same nurture_
from their birth up to the present time; they are both perfectly
healthy and strong, yet they are otherwise as dissimilar as two boys
could be, physically, mentally, and in their emotional nature."
(2.) "I can answer most decidedly that the twins have been perfectly
dissimilar in character, habits, and likeness from the moment of
their birth to the present time, though they were nursed by the same
woman, went to school together, and were never separated till the
age of fifteen."
(3.) "They have never been separated, never the least differently
treated in food, clothing, or education; both teethed at the same
time, both had measles, whooping-cough, and scarlatina at the same
time, and neither had had any other serious illness. Both are and
have been exceedingly healthy, and have good abilities, yet they
differ as much from each other in mental cast as any one of my
family differs from another."
(4.) "Very dissimilar in body and mind: the one is quiet, retiring,
and slow but sure; good-tempered, but disposed to be sulky when
provoked;--the other is quick, vivacious, forward, acquiring easily
and forgetting soon; quick-tempered and choleric, but quickly
forgiving and forgetting. They have been educated together and never
separated."
(5.) "They were never alike either in body or mind, and their
dissimilarity increases daily. The external influences have been
identical; they have never been separated."
(6.) "The two sisters are very different in ability and disposition.
The one is retiring, but firm and determined; she has no taste for
music or drawing. The other is of an active, excitable temperament:
she displays an unusual amount of quickness and talent, and is
passionately fond of music and drawing. From infancy, they have been
rarely separated even at school, and as children visiting their
friends, they always went together."
(7.) "They have been treated exactly alike both were brought up by
hand; they have been under the same nurse and governess from their
birth, and they are very fond of each other. Their increasing
dissimilarity must be ascribed to a natural difference of mind and
character, as there has been nothing in their treatment to account
for it."
(8.) "They are as different as possible. [A minute and unsparing
analysis of the characters of the two twins is given by their father,
most instructive to read, but impossible to publish without the
certainty of wounding the feelings of one of the twins, if these
pages should chance to fall under his eyes.] They were brought up
entirely by hand, that is, on cow's milk, and treated by one nurse
in precisely the same manner."
(9.) "The home-training and influence were precisely the same, and
therefore I consider the dissimilarity to be accounted for almost
entirely by innate disposition and by causes over which we have no
control."
(10.) "This case is, I should think, somewhat remarkable for
dissimilarity in physique as well as for strong contrast in character.
They have been unlike in body and mind throughout their lives. Both
were reared in a country house, and both were at the same schools
till _aet._ 16."
(11.) "Singularly unlike in body and mind from babyhood; in looks,
dispositions, and tastes they are quite different. I think I may
say the dissimilarity was innate, and developed more by time than
circumstance."
(12.) "We were never in the least degree alike. I should say my
sister's and my own character are diametrically opposed, and have
been utterly different from our birth, though a very strong
affection subsists between us."
(13.) The father remarks:--"They were curiously different in body
and mind from their birth."
The surviving twin (a senior wrangler of Cambridge) adds:--"A fact
struck all our school contemporaries, that my brother and I were
complementary, so to speak, in point of ability and disposition. He
was contemplative, poetical, and literary to a remarkable degree,
showing great power in that line. I was practical, mathematical, and
linguistic. Between us we should have made a very decent sort of a
man."
I could quote others just as strong as these, in some of which the
above phrase "complementary" also appears, while I have not a single
case in which my correspondents speak of originally dissimilar
characters having become assimilated through identity of nurture.
However, a somewhat exaggerated estimate of dissimilarity may be due
to the tendency of relatives to dwell unconsciously on distinctive
peculiarities, and to disregard the far more numerous points of
likeness that would first attract the notice of a stranger. Thus in
case 11 I find the remark, "Strangers see a strong likeness between
them, but none who knows them well can perceive it." Instances are
common of slight acquaintances mistaking members, and especially
daughters of a family, for one another, between whom intimate
friends can barely discover a resemblance. Still, making reasonable
allowance for unintentional exaggeration, the impression that all
this evidence leaves on the mind is one of some wonder whether
nurture can do anything at all, beyond giving instruction and
professional training. It emphatically corroborates and goes far
beyond the conclusions to which we had already been driven by the
cases of similarity. In those, the causes of divergence began to act
about the period of adult life, when the characters had become
somewhat fixed; but here the causes conducive to assimilation began
to act from the earliest moment of the existence of the twins, when
the disposition was most pliant, and they were continuous until the
period of adult life. There is no escape from the conclusion that
nature prevails enormously over nurture when the differences of
nurture do not exceed what is commonly to be found among persons of
the same rank of society and in the same country. My fear is, that
my evidence may seem to prove too much, and be discredited on that
account, as it appears contrary to all experience that nurture
should go for so little. But experience is often fallacious in
ascribing great effects to trifling circumstances. Many a person has
amused himself with throwing bits of stick into a tiny brook and
watching their progress; how they are arrested, first by one chance
obstacle, then by another; and again, how their onward course is
facilitated by a combination of circumstances. He might ascribe much
importance to each of these events, and think how largely the
destiny of the stick had been governed by a series of trifling
accidents. Nevertheless all the sticks succeed in passing down the
current, and in the long-run, they travel at nearly the same rate. So
it is with life, in respect to the several accidents which seem to
have had a great effect upon our careers. The one element, that
varies in different individuals, but is constant in each of them, is
the natural tendency; it corresponds to the current in the stream,
and inevitably asserts itself.
Much stress is laid on the persistence of moral impressions made in
childhood, and the conclusion is drawn, that the effects of early
teaching must be important in a corresponding degree. I acknowledge
the fact, so far as has been explained in the chapter on Early
Sentiments, but there is a considerable set-off on the other side.
Those teachings that conform to the natural aptitudes of the child
leave much more enduring marks than others. Now both the teachings
and the natural aptitudes of the child are usually derived from its
parents. They are able to understand the ways of one another more
intimately than is possible to persons not of the same blood, and
the child instinctively assimilates the habits and ways of thought
of its parents. Its disposition is "educated" by them, in the true
sense of the word; that is to say, it is evoked, not formed by them.
On these grounds I ascribe the persistence of many habits that date
from early home education, to the peculiarities of the instructors
rather than to the period when the instruction was given. The marks
left on the memory by the instructions of a foster-mother are soon
sponged clean away. Consider the history of the cuckoo, which is
reared exclusively by foster-mothers. It is probable that nearly
every young cuckoo, during a series of many hundred generations, has
been brought up in a family whose language is a chirp and a twitter.
But the cuckoo cannot or will not adopt that language, or any other
of the habits of its foster-parents. It leaves its birthplace as
soon as it is able, and finds out its own kith and kin, and
identifies itself henceforth with them. So utterly are its earliest
instructions in an alien bird-language neglected, and so completely
is its new education successful, that the note of the cuckoo tribe
is singularly correct.
DOMESTICATION OF ANIMALS.[14]
[Footnote 14: This memoir is reprinted from the _Transactions of
the Ethnological Society_]
Before leaving the subject of Nature and Nurture, I would direct
attention to evidence bearing on the conditions under which animals
appear first to have been domesticated. It clearly shows the small
power of nurture against adverse natural tendencies.
The few animals that we now possess in a state of domestication were
first reclaimed from wildness in prehistoric times. Our remote
barbarian ancestors must be credited with having accomplished a very
remarkable feat, which no subsequent generation has rivalled. The
utmost that we of modern times have succeeded in doing, is to
improve the races of those animals that we received from our
forefathers in an already domesticated condition.
There are only two reasonable solutions of this exceedingly curious
fact. The one is, that men of highly original ideas, like the
mythical Prometheus, arose from time to time in the dawn of human
progress, and left their respective marks on the world by being the
first to subjugate the camel, the llama, the reindeer, the horse,
the ox, the sheep, the hog, the dog, or some other animal to the
service of man. The other hypothesis is that only a few species of
animals are fitted by their nature to become domestic, and that
these were discovered long ago through the exercise of no higher
intelligence than is to be found among barbarous tribes of the
present day. The failure of civilised man to add to the number of
domesticated species would on this supposition be due to the fact
that all the suitable material whence domestic animals could be
derived has been long since worked out.
I submit that the latter hypothesis is the true one for the reasons
about to be given; and if so, the finality of the process of
domestication must be accepted as one of the most striking instances
of the inflexibility of natural disposition, and of the limitations
thereby imposed upon the [15] choice of careers for animals, and by
analogy for those of men.
[Footnote 15: _Transactionsof the Ethnological Society_, 1865,
with an alteration in the opening and concluding paragraphs, and
with a few verbal emendations. If I had discussed the subject now
for the first time I should have given extracts from the and with a
few verbal emendations. If I had discussed the subject now for the
first time I should have given extracts from the works of the
travellers of the day, but it seemed needless to reopen the inquiry
merely to give it a more modern air. I have also preferred to let
the chapter stand as it was written, because considerable portions of
it have been quoted by various authors (_e.g._ Bagehot, _Economic
Studies_, pp. 161 to 166: Longman, 1880), and the original memoir is
not easily accessible.]
My argument will be this:--All savages maintain pet animals, many
tribes have sacred ones, and kings of ancient states have imported
captive animals on a vast scale, for purposes of show, from
neighbouring countries. I infer that every animal, of any pretensions,
has been tamed over and over again, and has had numerous
opportunities of becoming domesticated. But the cases are rare in
which these opportunities have led to any result. No animal is
fitted for domestication unless it fulfils certain stringent
conditions, which I will endeavour to state and to discuss. My
conclusion is, that all domesticable animals of any note have long
ago fallen under the yoke of man. In short, that the animal creation
has been pretty thoroughly, though half unconsciously, explored, by
the every-day habits of rude races and simple civilisations.
It is a fact familiar to all travellers, that savages frequently
capture young animals of various kinds, and rear them as favourites,
and sell or present them as curiosities. Human nature is generally
akin: savages may be brutal, but they are not on that account devoid
of our taste for taming and caressing young animals; nay, it is not
improbable that some races may possess it in a more marked degree
than ourselves, because it is a childish taste with us; and the
motives of an adult barbarian are very similar to those of a
civilised child.