Popular Science Monthly/Volume 58/April 1901/A Study of British Genius III
|A STUDY OF BRITISH GENIUS.|
IV. HEREDITY AND PARENTAGE.
THE heredity of intellectual genius has been very fully discussed, with special reference to eminent persons of British birth, by Mr. Francis Galton. With, perhaps, even an excess of zeal—for persons of somewhat minor degrees of ability have sometimes been taken into account—Mr. Galton has shown that intellectual ability has frequently tended to run in families. If this hereditary tendency is by no means omnipresent, the present data prove conclusively that it is a very real factor. Notwithstanding that the effects of hereditary position have been so far as possible excluded, and that our lists only include persons of preeminent ability, distributed over fifteen centuries, it is yet found that among these 902 persons there are 31 groups, of two or three individuals in each group, who are closely related. These groups include 65 persons in all. The recognized relationships are father and son, brother and brother, brother and sister, sister and sister, uncle and nephew, aunt and nephew, uncle and niece, grandfather and grandson. Cousinship and more remote relationships also occur, but have not been included. In nineteen of these groups the ability shown may be said to be of a similar kind; in twelve it may be said to be of different kinds. There are only three cases in which the group consists of three persons: the Bacons, the Kembles, the Wordsworths. It is scarcely necessary to remark that in a very large number of cases the preeminent persons in our list were nearly related to other eminent persons who have not reached the degree of distinction entitling them to appear in the list. Of these no note has been taken.
I have, however, noted every case in which it is stated or implied that one or other, or both, of the parents possessed an unusual amount of intellectual ability, by no means necessarily involving any degree whatever of 'eminence.' These cases are very numerous, and as such ability may often have been displayed in very unobtrusive ways, it must frequently have escaped the attention of the national biographers. In 123 cases the father showed such ability; in 65 cases the mother is noted as of unusual ability, or else as being closely related to some person of eminent ability; in 20 of the 65 cases the mother was closely related to some person of very eminent ability, and may, therefore, be fairly presumed to have transmitted an intellectual aptitude whether or not she showed marked signs of such aptitude herself. In 14 cases both the father and the mother probably transmitted intellectual aptitudes. Making allowances for this, it may be said that at least 181 men and women of distinguished ability, or about 20 per cent, of our 902 eminent persons, have inherited intellectual aptitudes. Bearing in mind that in many cases the aptitudes of the parents are unknown or have passed unnoticed, and that in other cases the national biographers have failed to record known facts, it is not improbable that the proportion of cases in which one or other of the parents of our 902 eminent persons displayed more than average intellectual ability may be at least doubled.
If we consider the eminent women separately we find that, while 8 have had fathers of unusual intellectual ability, only 2 have had mothers from whom it can be said that they probably inherited. In one further case (Fanny Burney) both parents possessed ability, the father, however, in a more eminent degree than the mother. Moreover, the two cases in which the mother may probably be said to have transmitted the ability (Mrs. Siddons and Joanna Baillie) are more dubious than those in which it was transmitted by the father. So far as the present very limited data go, it seems probable, therefore, that women have a still more marked tendency than men to inherit intellectual aptitudes from their fathers.
It would be interesting to inquire into the moral and emotional qualities, the 'character,' of the parents. This, however, is extremely difficult and I have not attempted it. If we could do so we might find that the mothers of eminent men have had greater influence on their sons than the facts, so far as it has been possible to ascertain them, regarding the transmission of purely intellectual aptitudes would lead us to believe. In a great many cases the mother was a woman of marked piety, and we are frequently led to infer an unusual degree of character on the part of the mother, if not of the father. Moral qualities are quite as essential to most kinds of genius as intellectual qualities, and they are, perhaps, even more highly transmissible. They form the basis on which intellectual development may take place, and they may be transmitted by a parent in whom such development has never occurred. The very frequent cases in which men of eminent intellectual ability have declared that they owed everything to their mothers have sometimes been put aside as the expressions of an amiable weakness. It requires some credulity, however, to believe that men of preeminent, or even less than preeminent, intellectual acuteness are unable to estimate the character of their own parents. The frequent sense of indebtedness to their mothers expressed by eminent men may be taken as largely due to the feeling that the inheritance of moral or temperamental qualities is an even more massive and important inheritance than definite intellectual aptitudes. Such inheritance coming to intellectual men from their mothers may often be observed where no definite intellectual aptitudes have been transmitted. It is not, however, of a kind which can well be recorded in biographical dictionaries, and I have not, therefore, attempted to estimate its frequency in the group of preeminent persons under consideration.
I have, however, attempted to estimate the frequency of one other form of anomaly in the parents besides intellectual ability. The parents of persons of eminent intellectual power may not themselves have been characterized by unusual intellect; but they may have shown mental anomaly by a lack of aptitude for the ordinary social life in which they were placed. In at least 31 cases (or over 3 per cent.) we find that the father was idle, drunken, brutal, extravagant, unsuccessful in business, shiftless, or otherwise a ne'er-do-weel. In such cases, we may conclude, the father has transmitted to his eminent child an inaptness to follow the beaten tracks of life, but he has not transmitted any accompanying aptitude to make new individual tracks. This list could easily be enlarged if we included milder degrees of ineffectiveness, such as marked the father of Dickens (supposed to be represented in Micawber). A certain degree of inoffensive eccentricity, recalling Parson Adams, seems to be not very uncommon among the fathers of men of eminent ability, and perhaps furnishes a transmissible temperament on which genius may develop. It may be noted that 5 of the ne'er-do-weel fathers (a very large proportion) belonged to eminent women. Whether this confirms the conclusion already suggested as to the special frequency of paternal transmission in the case of women of eminent ability I cannot undertake to say. It may be added, however, that a ne'er-do-weel father, by forcing the daughter to leave home or to provide for the family, furnishes a special stimulus to her latent ability.
In 276 cases I have been able to ascertain with a fair degree of certainty the size of the families to which these persons of eminent ability belong. A more than fair degree of certainty has not been attainable, owing to the loose and inexact way in which the national biographers frequently state the matter. Sometimes we are only told that the subject of the article is 'the child' or 'the son'; this may mean the only child, but it is impossible to accept such a statement as evidence regarding the size of the family, and the number of families with only children may possibly thus have been unduly diminished. Again, the biographers in a very large number of cases ignore the daughters, and from this cause again their statements become valueless. In estimating the natality of the families producing children of ability I have never knowingly reckoned the offspring of previous or subsequent marriages; so far as possible, we are only concerned with the fecundity of the two parents of the eminent persons. So far as possible, also, I have reckoned the gross fecundity, i. e., the number of children born, not the number of children surviving; in the case of a large number of eminent men this gross fertility is known from the inspection of parish registers; in a certain proportion of cases it is probable, however, that we are only dealing with the surviving children. On the whole, the ascertainable size of the family may almost certainly be said to be under the mark. It is, therefore, the more remarkable that the average size of genius producing families is found to be larger than that of normal families. The average of the normal English family is at the very most 6; the average size of our genius-producing families is 7 (more exactly, 6.96). In order to effect an exact comparison I have looked about for some fairly comparable series of figures, and am satisfied that I have found it in the results of an inquiry by Mr. F. Howard Collins concerning 4,390 families. These families furnish an excellent normal standard for comparison; they deal mainly with 'Anglo-Saxon' people (in England and America) of the middle and upper classes; they represent, with probably but very slight errors of record, gross fertility; they are apparently not too recent, and they betray little evidence of the artificial limitation of families. The mean size of Collins's group of fertile families is found by Pearson to be 4.52 children. Comparing in more detail the composition of our genius-producing families with the normal average, we obtain the following results:
|Size of family||1||2||3||4||5||6||7||8|
|Size of family||9||10||11||12||13||14||over 14|
Unless, as is scarcely probable, the mental eccentricities of biographers lead to very frequent selection on definite lines, it will be seen that there is a very marked tendency for genius-producing families to be abnormally large. In genius-producing families there is an invariable deficiency of families below the average normal size, and an invariable excess of families above that size. In the largest size group (over 14) the excess becomes extravagantly large; this, however, may be partly accounted for; we may be sure that the biographers have seldom failed to record families of this size, so this group has really been recruited from the families of all our 902 eminent persons. Even on this basis, however, it remains extremely large; in Denmark, for instance, it is stated, a family of 22 children only occurs once in 34,000 marriages.
If, as seems probable, it may be asserted that genius-producing families are characterized by a tendency to an abnormally high birth-rate, this is not a fact to cause surprise. It might, indeed, have been anticipated. The mentally abnormal classes generally belong to families with a high birth-rate. This has been shown by Ball and Regis (confirmed by Marandon de Montyel) to be markedly the case as regards the insane. Magri has found it to be the case as regards criminals, as well as regards the epileptic, hysterical and neurasthenic.
An interesting point, and one which can scarcely be affected at all by any twist in the biographical mind, is the fact that our men of ability (the women are here excluded) are the offspring of predominantly boy-producing parents. Taking the 64 families in which the number of boys and girls in the family is clearly stated, and excluding 12 of these as consisting only of boys, we find that there are about 6 boys to 5 girls, or more exactly, 111 boys to 100 girls. The normal proportion of the sexes at birth at the present time in England is about 104 boys to 100 girls. It is in accordance with the predominantly boy-producing tendency of families yielding men of genius that the families yielding women of genius should show a predominantly girl-producing tendency. Here, indeed, our cases are far too few to prove much, but the results are definite enough so far as they go. Putting aside the families consisting only of girls, the sexual ratio is rather more than 3 boys to 4 girls, or more exactly, in the ratio of 85 boys to 100 girls. Putting the matter in another way, we may say that, while in every ten families from which men of genius spring, the boys predominate in six families, in ten families from which women of genius spring the boys predominate only in three.
I have made a tentative effort to ascertain what position in the family the child of genius is most likely to occupy. In a large number of cases we are only told his position as a son, not as a child; these are, of course, excluded. In order to investigate this point I considered the families of at least 8 children (and subsequently those of at least 7 children) and noted where the genius child came. This showed a very abnormally large proportion of eminent first children, and also abnormally few second and third children. Suspecting that certain peculiarities of the biographical mind (needless to enter into here, since we are not investigating the psychology of biographers) may have somewhat affected this result, I have confined myself to a simple inquiry less likely to be affected by any mental tendencies of the biographers. In families of different sizes, what relation do eldest genius children and youngest genius children bear to genius children of intermediate position? The results are very decisive. If, for instance, we take families of 7 children, it is found that they yield 8 eldest children of ability and
3 youngest, but only 10 for all the intermediate positions. If we take 8-children families, there are 3 eldest children of ability and 3 youngest, but only 10 intermediate. Again, 9-children families show as many as
4 eldest children of ability and 4 youngest, but only 1 intermediate child. So with 10-children families, there are 3 eldest children of ability and 3 youngest, but only 3 for all intermediate positions. It is so with families of 11 children and of 13 children. The only exception I have detected is in the case of 12-children families, in which group youngest children are wanting. So marked is the preponderance of eldest and youngest children of ability that only in two of these seven groups (7-children families to 13-children families) do the intermediate children of ability exceed in number the eldest and youngest children combined. It is evident that there is a special liability for eldest and youngest children to be born with intellectual aptitudes, the liability being greater in the case of the former than of the latter, for there are in the seven groups 24 eldest children to 18 youngest children, the intermediate children numbering 40.
Here again the results, however remarkable they may appear, are strictly such as we might have been led to expect. In the other mentally abnormal classes we find exactly similar phenomena. Thus, among 433 idiots Mitchell found that 138 were first-born children and 89 last-born children; so that here not only were the eldest and youngest children in an absolute majority over all those of intermediate position, but the eldest had to the youngest almost the same ratio (4 to 3) as we have found in the genius group. Shuttleworth has lately stated that among the so-called 'Mongolian' variety of imbeciles quite 40 per cent. are the youngest members of large families. Bohannon found that youngest children tend to be exceptional and abnormal, precocity being a specially prominent trait among them. Among the socially degenerate classes Dugdale found first-born and last-born prominent, the former tending to be criminals, the latter paupers.
Whenever it has been possible I have noted the age of the father at the birth of his eminent child. It has been possible to ascertain this in 204 cases, and the data thus obtained may be considered as fairly free from fallacy, so far as the biographical mind is concerned. The range of age is considerable, from 15, the age of Napier of Merchiston's father at his birth, to 79, the age of Charles Leslie's father, the period of potency in the case of the fathers of persons of eminent ability thus ranging over 64 years. The 204 cases may be grouped in five-year age-periods as follows:
|Under 20||20-24||25-29||30-34||35-39||40-44||45-49||50-54||55-59||60 and over|
These figures run in a fairly smooth and regular way, and I believe that they are very noteworthy and significant. It will be seen that 30-34 is the most frequent age of fatherhood, and that while there are very few cases of fatherhood during the ten preceding years, when sexual vigor is at its height, the majority of eminent persons have been begotten by fathers who had already passed this age of most frequent fatherhood. This result is the more significant when we remember that we are chiefly dealing with the upper social classes (for it is in their cases that these facts are most easily ascertained), and that we must exclude the quite modern tendency to retardation of the age of marriage. I have no figures of the age of fatherhood among normal subjects quite fairly comparable with those here presented. The significance of the age of fatherhood has been chiefly studied, so far as I am aware, by Marro in North Italy, and we cannot assume that the conditions are there quite the same. Marro divided the fathers of his normal subjects into three classes: (1) Below 25 years of age, a stage of immaturity; (2) from 26 to 40 years of age, a stage of maturity; (3) over 40 years of age, a stage of decadence. He found that 8.8 per cent, fathers of normal subjects belonged to the first group, 66.1 to the second class and 24 to the third. The corresponding figures for the fathers of the persons of eminent ability concerned in the present inquiry are 3.9, 57.3 and 38.7. Whatever the value of this comparison, there can be little doubt that an abnormally high age prevails among the fathers of our eminent persons. I have only been able to ascertain the age of the mother in 40 instances. In these cases it is distributed as follows:
|Age of mother||21-24||25-29||30-34||35-39||40-44||45-49||50|
|Number of cases||8||13||8||5||4||1||1|
Except for the one very unusual instance at 50 (Dibdin's mother), this distribution seems to indicate that the mothers of persons of intellectual ability are predominantly at the period of greatest vigor and complete sexual maturity when they produce their distinguished children., Notwithstanding the tendency of first-born children to show intellectual ability, none of the mothers are under 21.
It may be noted that in at lea«t 36 of the 276 cases in which we have details of the family history (or in about 13 per cent.) the mother was a second or third wife. In at least 6 cases the father was a second husband.
It would have been instructive to compare the ages of the parents and to ascertain the degree of disparity. I have only been able to do this in 34 cases. There is a marked tendency to disparity which ranges up to 49 years. Whatever may be the normal amount of disparity between the ages of parents, it certainly tends to range chiefly below 4 years, but in this group only 8 cases (i. e., in the proportion of about 23 per cent.) show less disparity than 4 years; the majority range between 4 and 8 years, and as many as 8 (i. e., in the proportion of over 22 per cent.) show a greater disparity than 10 years. In 6 out of the 34 cases the mother was older than the father. In a considerable proportion of cases both parents were elderly.
On the whole it would appear, so far as the evidence goes, that the fathers of our eminent persons have been predominantly middle-aged and to a marked extent elderly at the time of the distinguished child's birth; while the mothers have been predominantly at the period of greatest vigor and maturity, and to a somewhat unusual extent elderly. There has certainly been a notable deficiency of young fathers, and, still more notably, of young mothers.
Our data at this point are too few to be very decisive, but, so far as they indicate anything, they enable us once again to bring men of 'genius' into line with the other mentally abnormal classes. The late Dr. Langdon Down (who at my suggestion investigated the point some twelve years ago) found that in the case of the parents of idiots there was a disparity of more than ten years in 23 per cent, cases, almost the same proportion as we have found in the parents of persons of intellectual ability. Among criminals also inequality of age in the parents, as well as elderly age of both parents, has been found by Marro to be more common than among the normal population. Marro (in his ' Caratteri dei Delinquenti' and 'La Pubertà') has investigated the whole question of the influence of the age of the parent on the character of the child. He has found that when both parents are in the same period of age development elderly parents produce the highest proportion of 'very intelligent' children (though not the highest proportion of 'intelligent' children). Marro has also found that, taking the fathers alone, although 'intelligent' children are mostly the offspring of young fathers, 'very intelligent' children are mostly the offspring of middle-aged and elderly fathers. He finds much the same result as regards mothers. He found that the insane show an excess of elderly fathers, while murderers show a deficiency of young fathers and a very great excess of elderly fathers. The highest proportion of defectively intelligent children (this harmonizing with Langdon Down's results) Marro also found among the offspring of elderly fathers. Elderly fathers and very young mothers were found by Marro to produce the largest proportion; of 'good conduct' children, but not of intelligent children.
- See especially his 'Hereditary Genius.'
- It is quite possible, however, that such remote relationships are not without significance. One cannot but be struck by such a fact as the relationship of Shelley through his mother with the lyric poet Southwell, with whom he has so real an emotional affinity.
- A remark of Huxley's in a letter to the present writer—"Mentally and physically I am a piece of my mother"—may be taken as typical of such declarations.
- This was the average fertility of 1,700 marriages, as ascertained by Ansell, Duncan, 'Sterility in Women,' p. 4. Galton found the mean of 204 marriages 4.65, and Pearson the mean of 378 fertile marriages 4.70.
- As quoted by Karl Pearson, 'The Chances of Death,' Vol. I., p. 70. In passing through Mr. Pearson's mathematical hands the 4,390 emerge as 4,444, and it is on this number that my percentages for normal families are based.
- This tendency has already been noted by Galton when investigating English men of science, and by Yoder in studying a small miscellaneous group of eminent men.
- In our genius-producing group there are 4 families of more than 19 children. Doddridge was the youngest of 20 children; Popham was the youngest of his mother's 21 children; Colet was the eldest and only surviving child of 22; Dempster was, or stated himself to be, the 24th, of 29 children. There was a strong tinge of romance about Dempster, and 1 fear that we cannot accept this statement with such complete confidence as would be desirable.
- This very exceptional case was that of the father (an eminent bishop) of Charles Leslie, the nonjuring divine. In this case the father was 79, the mother 30.
- In Hungary, as a table given by Körösi shows, if we take men at ages between 26 and 30, covering the most frequent normal age of marriage, in only 3 per cent, cases is the discrepancy of age as much as ten years. The disparity, of course, tends to increase with the man's higher age at marriage.