matings, the union of a very short man with a very tall woman occurred but once, or one-tenth of the probable number of times according to the law of chance, and the opposite kind of mating did not occur at all. Miss Elderton has made an attempt to compare mental traits of married couples and has found a perceptible degree of resemblance in the following characters, the figures representing the degree of correlation: intelligence -33, temper .18, excitability .11, sympathy .15, reserve .27.

Assortative mating is common among some of the defective classes. Pearson found that tuberculosis occurred in both husband and wife to an appreciable extent, the correlation being .24; and he concluded that it was due to assortative mating and not to infection. His explanation was that certain types tend to mate, and some of his figures certainly support his view; but in this particular illustration mating is probably in part the result of association, for the infected of both sexes frequent the same health resorts. The congenitally deaf marry to a very noticeable extent, owing partly to association and partly to sympathy and similarity of habits. From a study of 7,277 deaf mutes it was found that of those who had attended boarding schools for the deaf, 86.2% married deaf mutes; and of those who did not attend a special school for the deaf 62.4% married deaf mutes. It is noteworthy also that the mentally defective, especially the feeble-minded, tend to intermarry; partly because of segregation and partly because they are rejected by the normal.

Another kind of assortative mating deserving mention is occupational. Since women have entered industry extensively, it has been found that individuals in the same occupations tend to marry. In a study of such marriages in Philadelphia, L. M. Marvin 2 shows that among the American population there are 2.79 times as many marriages within occupations as would take place if matings were merely a matter of chance. The fact itself is not at all surprising; its interpretation is the important point. Marriages within occupations are chiefly due to propinquity, but wherever there is free choice of occupations such marriages

1 Publications of the American Statistical Association, 16: 131.

may indicate similarity of mental capacity and taste. For example, the rather common occurrence of marriages within the medical profession, where a very considerable specialized training is necessary, probably indicates similarity of traits, which would supply a normal basis for preference. On the other hand, marriages in manufacturing or mercantile groups, where little preliminary specialized training is required, are chiefly the result of propinquity and are of little significance in the problem of sexual mating.

Assortative mating is explained by the psycho-analysts on the ground that the feminine ideal is derived from or influenced by the mother image. Therefore if a man selects in accordance with this ideal, his wife will be likely to possess traits similar to his own. However, the mating of similars would not seem unnatural, even without this supposition concerning the source of the ideal. It seems both natural and desirable that individuals should choose mates having similar tastes and interests; and in so doing they would be selecting individuals with many mental qualities like their own. Whether or not a real correlation exists between particular physical and mental traits is not known, though according to popular opinion such is the case. Anyhow it is possible that physical and mental traits are not chosen on the same basis. The physical type preferred might correspond to the family type, and similarity in mental traits might indicate congeniality. The degree of similarity of couples for most traits is not high; but, inasmuch as assortative mating is found in the middle class where choice is supposed to be freest, the conclusion is that the mating of like with like is the natural and desirable form of mating. This conclusion is not, however, fully established yet for all kinds of traits.

From the point of view of heredity, it is evident that assortative mating must result in a stronger transmission of the similar parental traits to offspring; and therefore its desirability from this aspect must depend upon the social utility of the traits possessed by the parent.

Assortative mating should not be interpreted as a force tending to make the sexes more alike. It does not mean that men choose women having masculine traits, but rather that they choose women having feminine manifestations of their particular traits. Take for example a physical character such as stature. A shorter stature for women seems to be a sex characteristic; and, if agreeable to both sexes, it will be continued through selection. But tall men could still marry tall women and short men short women without interfering with the relative height of the sexes. In all cases the women might be shorter than the men. Many characteristics, however, which are evidently the objects of selection, such as complexion, have no sexual significance.

Causes of Defective Sexual Mating. Conditions which interfere with ideal sexual mating are quite similar to those which affect sexual selection, and they need be restated here only as they may have new or peculiar application to sexual mating. Disabilities arising out of limited acquaintance are probably even more significant for sexual mating than for sexual selection. A narrow circle of association probably results less frequently in the union of persons absolutely unfitted to marry than in the union of persons unsuited to each other. Other things being equal the larger the circle of acquaintance the more easily will individuals find suitable mates. This is true whether marriage results from the free choice of the parties themselves, as is usually the case among Anglo-Saxon peoples, or whether it is left to the judgment of parents or guardians, as is more frequently the case in Latin countries.

The dangers arising from choices made by the immature also deserve emphasis in connection with sexual mating. The exceptionally large number of divorces, and also of suicides, among the married under twenty years of age, indicate that precocious marriages are less successful than the average. These failures are due partly to the assumption of the responsibilities of married life by persons too youthful, but are traceable also to mistakes in choice of mates because of immaturity. The same objection can be made to hasty marriages upon short acquaintance. Such marriages result from a passing impulse based upon sudden fancy before the real character and temperament of the parties can be known, and therefore the chance of mutual congeniality will be small.

The preservation by each sex of high ideals of the opposite sex has a similar significance both for sexual selection and for sexual mating. The most desirable and lasting unions result from high sex ideals and high standards concerning the marriage relation. This view is not however unchallenged. It has been charged, for instance, that college women maintain such high sex requirements that mating is made difficult if not impossible; and that therefore the higher education of women is opposed to the interests of the race. Education probably does raise the standards of women; it would be a serious reflection upon education if it did not. It may also interfere with the subordination and docility of women and make them reluctant to submit to a servile form of marriage; but there is no evidence that it promotes ideals which make women opposed to union with equals upon equal terms. Lofty idealism is not a social malady. And when women do not marry, the blame should not be ascribed to their education, but, here again, to restricted association, which keeps them from contact with men of similar ideals and attainments. The cultivation of high ideals must be accompanied with broad association. And the economic independence of women will probably aid in bringing actual mating into conformity with the ideal. Interesting employment, affording opportunity for selfsupport, will deter women from ill-advised matches and will enable them to wait for congenial mates.

Methods of Improving Sexual Mating. The process of sexual mating will be improved along with that of sexual selection and by much the same means. The measures which will prove of particular significance for sexual mating are: enlargement of circles of acquaintance, postponement of choice until the period of maturity, and removal of impediments or restrictions to normal acquaintance. The first two of these ends are likely to be attained gradually through the normal course of social development without conscious effort. Enlarged circle of acquaintance usually comes with improved means of communication and with the perfecting of social institutions; but, as has been shown, there are numerous exceptions, and progress could be hastened and improvements made more general by carefully instituted reforms. It is also probable that the age of marriage, and with it usually the age of choice, is gradually deferred as

population becomes denser and economic competition keener. Advanced society calls for specialization and the supplementary training involved in specialization is inconsistent with youthful marriage.

On the other hand, it is in advanced societies particularly that social conventions arise which tend to interfere with the natural association of the sexes. When artificial conditions keep women from free and spontaneous contact with the opposite sex, men are likely to seek the companionship of women of inferior position. It is under these circumscribed relations in older societies that matches are most commonly made on the basis of wealth and social position rather than on the basis of mutual personal attraction. And whenever choices are determined by external conditions rather than by personal qualities both sexual selection and sexual mating have lost their efficacy.

REFERENCES FOR COLLATERAL READING CARVER, T. N., Sociology and Social Progress, Ch. 26. DARWIN, C., Sexual Selection. DUNLAP, K., Personal Beauty and Race Betterment. HARRIS, J. A., Assortative Mating in Man, Pop. Sci. Mon., 80: 476. HILL, C., Heredity and Selection in Sociology, Pt. I, Ch. 6. POPENOE and JOHNSON, Applied Eugenics. WILDE, A., Theory of Sex, Eugenics Review, 8: 189.