Page:Popular Science Monthly Volume 80.djvu/493

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IV. Assortative Mating for Psychical Characters

That psychical characteristics should play some part in human matings seems a priori highly probable.[1] Actual facts are, however, few.[2] Galton concluded[3] that even good and bad temper made very little difference in marriage selection, but he pointed out many difficulties of obtaining trustworthy evidence.

Elderton[4] found for "Intelligence, Temper, Temperament"[5] and success in career the values given in the accompanying table.[6]

Mental Character Relationship
Intelligence .33
Temper .18
Temperament, excitable .11
Sympathetic .15
Reserved .27
Success in career .48

For insanity, working with Pearson's "Family Records" and using two different methods of classifying the "normal," "insane," "nervous" and "doubtful" entries so as to get the upper and lower limits for assortative mating. Miss Elderton[7] finds + .244 as the lower and + .361 as the upper limit, say roughly an intensity of .30 ± .05.

  1. Theoretically, assortative mating should be absent in royalty where marriages are contracted by persons other than those most directly concerned, or are arranged in accordance with some political policy. Woods ("Mental and Moral Heredity in Royalty," pp. 272-273) thinks it can not be held to be entirely absent. He correlated the intellectual grades of 229 couples and found r = + .08, approximately, but with a probable error of ± .076.
  2. I have given none of the coefficient for psychical characters calculated by Schuster and Elderton (Biometrika, Vol. 5, pp. 460-469, 1907) from data collected by Heymans and Wiersma. These give results which vary widely among themselves and if one takes those which seem the most likely to be trustworthily determined, he opens himself to the criticism of the selection of evidence. Personally, I have grave doubts concerning the value of data on psychical characters collected by the widespread circulation of schedules. The estimates are too much subject to personal equation and family bias. When they are entrusted to especially trained observers who work comparatively, the ease is better.
  3. Galton, F., "Good and Bad Temper in English Families," Fortnightly Rev., July, 1887. Reprinted in "Natural Inheritance."
  4. Elderton, Ethel M., Draper's Co. Res. Mem., "Stud. Nat. Det," 3, pp. 30-35, 1908.
  5. Galton ("English Men of Science," p. 20, 1895) had only 22 cases where the temperamental characteristics of the parents were marked. He considers that there is a tendency for harmonious matings with respect to temperament.
  6. The signs, sometimes difficult to determine in the case of non-measurable characters, seem to be positive throughout, but in some cases there may be distinct cross currents, one tending to produce like and the other to give dissimilar unions. The intensity of resemblance for "success in career" is about double that for other characters, and is possibly to a large extent spurious, because subjective. The "success in career" of a wife is probably largely dependent on or judged by the opportunities which her husband's success gives her for displaying her own abilities.
  7. Elderton, Ethel M., loc. cit., p. 35.