Part 19 (1/2)
Marriages of individuals whose families are marked by minor taints can not justify social interference; but an enlightened conscience and a eugenic point of view should lead every individual to make as good a choice as possible.
If a eugenically bad mating has been made, society should minimize as far as possible the injurious results, by means of provision for properly restricted divorce.
Consanguineous marriages in a degree no closer than that of first cousins, are neither to be condemned nor praised indiscriminately. Their desirability depends on the ancestry of the two persons involved; each case should therefore be treated on its own merits.
CHAPTER XI
THE IMPROVEMENT OF s.e.xUAL SELECTION
”Love is blind” and ”Marriage is a lottery,” in the opinion of proverbial lore. But as usual the proverbs do not tell the whole truth.
Mating is not wholly a matter of chance; there is and always has been a considerable amount of selection involved. This selection must of course be with respect to individual traits, a man or woman being for this purpose merely the sum of his or her traits. Reflection will show that with respect to any given trait there are three ways of mating: random, a.s.sortative and preferential.
1. Random mating is described by J. Arthur Harris[95] as follows:
”Suppose a most highly refined socialistic community should set about to equalize as nearly as possible not only men's labor and their recompense, but the quality of their wives. It would never do to allow individuals to select their own partners--superior cunning might result in some having mates above the average desirability, which would be socially unfair!
”The method adopted would be to write the names of an equal number of men and women officially condemned to matrimony on cards, and to place those for men in one lottery wheel and those for women in another. The drawing of a pair of cards, one from each wheel, would then replace the 'present wasteful system' of 'compet.i.tive' courts.h.i.+p. If the cards were thoroughly shuffled and the drawings perfectly at random, we should expect only chance resemblances between husband and wife for age, stature, eye and hair color, temper and so on; in the long run, a wife would resemble her husband no more than the husband of some other woman. In this case, the mathematician can give us a coefficient of resemblance, or of a.s.sortative mating, which we write as zero. The other extreme would be the state of affairs in which men of a certain type (that is to say men differing from the general average by a definite amount) always chose wives of the same type; the resemblance would then be perfect and the correlation, as we call it, would be expressed by a coefficient of 1.”
If all mating were at random, evolution would be a very slow process.
But actual measurement of various traits in conjugal pairs shows that mating is very rarely random. There is a conscious or unconscious selection for certain traits, and this selection involves other traits because of the general correlation of traits in an individual. Random mating, therefore, need not be taken into account by eugenists, who must rather give their attention to one of the two forms of non-random mating, namely, a.s.sortative and preferential.
2. If men who were above the average height always selected as brides women who were equally above the average height and short men selected similarly, the coefficient of correlation between height in husbands and wives would be 1, and there would thus be perfect a.s.sortative mating. If only one half of the men who differed from the average height always married women who similarly differed and the other half married at random, there would be a.s.sortative mating for height, but it would not be perfect: the coefficient would only be half as great as in the first case, or .5. If on the other hand (as is indeed the popular idea) a tall man tended to marry a woman who was shorter than the average, the coefficient of correlation would be less than 0; it would have some negative value.
Actual measurement shows that a man who exceeds the average height by a given amount will most frequently marry a woman who exceeds the average by a little more than one-fourth as much as her husband does. There is thus a.s.sortative mating for height, but it is far from perfect. The actual coefficient given by Karl Pearson is .28. In this case, then, the idea that ”unlikes attract” is found to be the reverse of the truth.
If other traits are measured, a.s.sortative mating will again be found.
Whether it be eye color, hair color, general health, intelligence, longevity, insanity, or congenital deafness, exact measurements show that a man and his wife, though not related by blood, actually resemble each other as much as do uncle and niece, or first cousins.
In some cases a.s.sortative mating is conscious, as when two congenitally deaf persons are drawn together by their common affliction and mutual possession of the sign language. But in the greater number of cases it is wholly unconscious. Certainly no one would suppose that a man selects his wife deliberately because her eye color matches his own; much less would he select her on the basis of resemblance in longevity, which can not be known until after both are dead.
Sigmund Freud and Ernest Jones explain such selection by the supposition that a man's ideal of everything that is lovely in womankind is based on his mother. During his childhood, her attributes stamp themselves on his mind as being the perfect attributes of the female s.e.x; and when he later falls in love it is natural that the woman who most attracts him should be one who resembles his mother. But as he, because of heredity, resembles his mother, there is thus a resemblance between husband and wife. Cases where there is no resemblance would, on this hypothesis, either be not love matches, or else be cases where the choice was made by the woman, not the man. Proof of this hypothesis has not yet been furnished, but it may very well account for some part of the a.s.sortative mating which is so nearly universal.
The eugenic significance of a.s.sortative mating is obvious. Marriage of representatives of two long-lived strains ensures that the offspring will inherit more longevity than does the ordinary man. Marriage of two persons from gifted families will endow the children with more than the ordinary intellect. On the other hand, marriage of two members of feeble-minded strains (a very common form of a.s.sortative mating) results in the production of a new lot of feeble-minded children, while marriage contracted between families marked by criminality or alcoholism means the perpetuation of such traits in an intensified form. For alcoholism, Charles Goring found the resemblance between husband and wife in the following cla.s.ses to be as follows:
Very poor and dest.i.tute .44 Prosperous poor .58 Well-to-do .69
The resemblance of husband and wife, in respect of possession of a police record, he found to be .20. Of course alcoholism and criminality are not wholly due to heredity; the resemblance between man and wife is partly a matter of social influences. But in any case the existence of a.s.sortative mating for such traits is significant.
3. Preferential mating occurs when certain cla.s.ses of women are discriminated against by the average man, or by men as a cla.s.s; or _vice versa_. It is the form of s.e.xual selection made prominent by Charles Darwin, who brought it forward because natural selection, operating solely through a differential death-rate, seemed inadequate to account for many phases of evolution. By s.e.xual selection he meant that an individual of one s.e.x, in choosing a mate, is led to select out of several compet.i.tors the one who has some particular attribute in a high degree. The selection may be conscious, and due to the exercise of aesthetic taste, or it may be unconscious, due to the greater degree of excitation produced by the higher degree of some attribute. However the selection takes place, the individual so selected will have an opportunity to transmit his character, in the higher degree in which he possesses it, to his descendants. In this way it was supposed by Darwin that a large proportion of the ornamental characters of living creatures were produced: the tail of the peac.o.c.k, the mane of the lion, and even the gorgeous coloring of many insects and b.u.t.terflies. In the early years of Darwinism, the theory of s.e.xual selection was pushed to what now seems an unjustifiable extent. Experiment has often failed to demonstrate any s.e.xual selection, in species where speculation supposed it to exist. And even if s.e.xual selection, conscious or unconscious, could be demonstrated in the lower animals, yet the small percentage of unmated individuals indicates that its importance in evolution could not be very great.[96]
[Ill.u.s.tration: HOW BEAUTY AIDS A GIRL'S CHANCE OF MARRIAGE
FIG. 32.--Graph showing the marriage rate of graduates of a normal school, correlated with their facial attractiveness as graded by estimates. The column of figures at the left-hand side shows the percentage of girls who married. Of the prettiest girls (those graded 80 or over), 70% married. As the less attractive girls are added to the chart, the marriage rate declines. Of the girls who graded around 50 on looks, only about one-half married. In general, the prettier the girl, the greater the probability that she will not remain single.]
In man, however, there is--nowadays at least--a considerable percentage of unmated individuals. The Census of 1910 shows that in the United States one-fourth of all the men between 25 and 44 years of age, and one-sixth of all the women, were unmarried. Many of the men, and a smaller number of the women, will still marry; yet at the end there will remain a large number, particularly in the more highly educated cla.s.ses, who die celibate. If these unmated individuals differ in any important respect from the married part of the population, preferential mating will be evident.
[Ill.u.s.tration: INTELLIGENT GIRLS ARE MOST LIKELY TO MARRY