Page:Popular Science Monthly Volume 62.djvu/503

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Regression to the Mean.

BY taking each country separately and analyzing it minutely, we have seen how almost perfect heredity appears to be as a cause of the mental and moral peculiarities wherever found. In order to ascertain if talent is properly related to genius in point of consanguinity, so that we have a progressive falling off in relationship to 9, 10 grades as we descend from the high ranks to the mediocrities, a count has been made of the number of geniuses (9, 10 grades) which each person possesses as a blood relation both in the first degree of consanguinity and in the second. By the first degree is meant the number of geniuses who are as closely related as father, mother, brother, sister, son or daughter.

The second degree includes also grandparents, uncles, aunts, grandchildren, nephews and nieces. If the proportionate relationship of geniuses to men and women of their own type is greater for the first degree of relationship than for the second, we shall see the principle of heredity satisfied, especially if the ratio is the same as found by other observers for physical traits.

The curves show that such is the case, and we have an almost perfect rise in eminent relationship as we ascend from mediocrity to the highest scale. This is true for both the males and females. The average of both sexes smoothes out the curve and gives an even more regular rise than is given by each sex separately. It is to be remembered that such facts mean a great deal since were the geniuses scattered over the entire number, without any law of distribution in regard to blood—as I claim they should be from the effect of environment on the intellectual side at least—there would be instead a reverse of the facts, or an actual falling off in percentage of eminent relations among the higher grades.

This can be made clear by considering any one instance. Take the case of Catherine II. of Russia. All her near relations receive one count for being related to her, yet she herself receives no count, since none of her near relations stand in a 9 or 10 grade. The same would be true of Frederick the Great were he the only one in his immediate family who belonged to 9 or 10 grade. As a matter of fact he counts 6 such relations.

The accompanying curves (Plate I.) show the percentage of eminent (or 9, 10) relations which each grade possesses. The lower lines show