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An Investigation Into the Position in Family of Mental Defectives
Prepared for the Mental Deficiency Sub-Committee of the Research and Clinical Committee of the Royal Medico-Psychological Association
Published online by Cambridge University Press: 19 February 2018
Extract
This investigation was undertaken at the instance of the Mental Deficiency Sub-committee of the Research and Clinical Committee of the Association. It is an attempt to answer the question whether or not the order in which a mentally defective child is born into a family can have any influence as a cause of the mental defect.
- Type
- Part I.—Original Articles
- Information
- Copyright
- Copyright © Royal College of Psychiatrists, 1931
References
* Karl Pearson, On the Handicapping of the First-Born, 1914. G. F. Still, “On Place-in-family as a Factor in Disease,” Lancet, October, 1927, pp. 795 and 853. Google Scholar
* Neil A. Dayton, “Order of Birth and Size of Family,” Amer. Journ. of Psychiat., 5929, viii, p. 979. Google Scholar
* Annual Report of L.C.C., 1912 and 1925. Google Scholar
† In a given table, if (N1) be the number of only children, and (N2) the number of cases in families of 2 and (N3) the number of cases in families of 3, and so on, then the expectation of the number of first-born children is etc., and the expectation of the number of second-born is etc., and so on. For example, in Table II the values of N1, N2, etc., are given by the totals in the last line. Thus the expectation of first-born is— and the expectation of fifth-born is— Google Scholar
* Vol. iii, p. 191. Google Scholar
* Cf. M. T. MackIm, Amer. Journ. Med. Sci., 1929. Google Scholar
* The ages of the parents in ioo cases of non-mongolian defectives taken at random from the questionnaire papers were as follows: in the group of mongols the coefficient of correlation between the ages of mother and father was P68, and in the non-mongol group it was .69.Google Scholar
* Report of Research and Clinical Committee of the Royal Medico-Psychological Association, July, 5930. Google Scholar
† Op. cit. Google Scholar
* Feeble Mindedness: Its Causes and Consequences, 1916. Google Scholar
† e.g., H. S. Jennings, The Biological Basis of Human Nature, 1930. Google Scholar
* Let the size of the fraternity be n members and the expected proportion of affected members in all such fraternities be ¼. Assuming that the affected members are distributed at random in these fraternities, and that only those families come under observation which contain at least one affected member, the percentage of affected members in the observed families is given by the formula— A rough value for the expectation is obtained by putting the average size of the family for n. In this case n = 4.26.Google Scholar
† The deviation of the observed proportion of affected persons from the expected value is 6.1% which is more than four times the mean quadratic error of the expected value, 1.4%. Google Scholar
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