Intelligence of Unmarried Mothers, II
- Author:
McClure
The University of Toledo, Toledo, Ohio
A study of the intelligence of unmarried mothers who had been admitted to a home for unfortunate girls over a period of four years was published in 1929 by McClure and Goldberg.1 The study was based on the results of the Stanford-Binet test given to 84 girls. Eighty-seven had been examined but the scores of three were eliminated because of language difficulties.
Since 1929 an additional number of 77 girls has been admitted to the same home and given the Stanford-Binet test. The purpose of this present study is to present the results of the test scores made by the new group of 77 girls and to compare these results with the data presented in the 1929 study to show the correspondence between the two groups of data. This study also shows the results of the combined scores of the two groups of girls.
In Part II of the 1929 study is presented an analysis of the several mental traits measured by the Stanford-Binet test. Such an analysis is omitted in the present study.
Each of the three following tables contains three sets of data: first, the data presented in the 1929 study; second, data from the 77 girls examined since 1929, and third, data from the combined scores of the two groups. In each table “Old” refers to the 1929 data, “New” refers to the 77 girls, and “Combined” refers to the two groups combined.
Table I Intelligence op 161 Unmarried Mothers Number of girls tested Range of I. Q.’s Median I. Q Mean I. Q P.E. mean Old 84 38-109 76 77.09 1.057 New 77 53-107 76 79.07 .979 Combined 161 38-109 76 78.16 .729
i McClure, W. E., and Goldberg, Bronett, Intelligence of Unmarried Mothers, The Psychological Clinic, 1929, 18, 119-127. Table I shows that the average intelligence of the two groups of girls corresponds very closely. Both groups have the same median I. Q., which is 76. There is a difference of only two points between their mean I. Q.’s, the mean of the old group being 77.09 and of the new group, 79.07. The I. Q. range is greater for the old group than for the new. For the former it is 38 to 109 and for the latter it is 53 to 107. The combined scores of the two groups show very similar results. The I. Q. range is 38 to 109, the median I. Q. is 76, and the mean I. Q. is 78.16.
Table II Classification of the Intelligence of 161 Unmarried Mothers I. Q. Range Old Frequency Per cent New Frequency Per cent Combined Frequency Per cent Normal Dull normal. Borderline. . Moron Imbecile 90-109 80-89 70-79 50-69 25-49 16 22 20 23 3 19.0 26.2 23.8 27.4 3.6 17 12 30 18 0 22.1 15.6 38.9 23.4 00.0 33 34 50 41 3 20.5 21.1 31.1 25.4 1.9
Table II shows the frequency and per cent of I. Q.’s at each level from imbecile to normal intelligence. The two groups vary somewhat in this classification. The greatest differences are at the dull normal and the borderline levels. The old group has 26.2 per cent at the dull normal level, while the new group has only 15.6 per cent. At the borderline level the old group has 23.8 per cent while the new group has 38.9 per cent. The old group has 3.6 per cent imbeciles while the new group has none. At the normal and moron levels the two groups are quite similar. Nineteen per cent of the old group and 22.1 per cent of the new group are normal. At the moron level the old group has 27.4 per cent and the new group has 23.4 per cent.
After combining the scores of the two groups, making a total of 161, only 33 (or 20.5 per cent) of the girls are shown to have normal intelligence. The remaining 128 girls are shown to have subnormal intelligence classified according to mental levels as follows : 34 dull normals, 50 borderliners, 41 morons, and 3 imbeciles. Thus, 79.5 per cent of the girls have subnormal intelligence while only 20.5 have normal intelligence. Forty-four (or 27.3 per cent) are feebleminded.
These data indicate that the problem of unmarried mothers is not serious among girls with intelligence below the moron level nor above the normal level. It is shown in this study that the most critical level is the borderline level. Table II shows a greater frequency and a higher per cent at this level than at any other level. Moreover, the median and mean I. Q.’s (76 and 78.16 respectively) both lie at this level.
Table III Chronological Ages of 164 Unmarried Mothers Old New Combined Number of girls… Range of ages Median age Mean age P.E. mean Standard deviation. 87 * 13-41 18 18.37 .265 3.672 77 14-25 18 18.59 .181 2.359 164 13-41 18 18.49 .162 3.087
Included here are the chronological ages of the three girls whose I. Q. ‘s
were eliminated because of language difficulties.
Table III shows the mean and median ages of the two groups to be practically the same. The mean is 18.37 for the old group, and 18.59 for the new, while for the two groups combined it is 18.49. The median age is 18 for each of the two groups as well as for the two groups combined. The old group is shown to have a much larger range of ages than the new group, 13-41 and 14-25 respectively. But this difference is not so great as it may seem because the age of “41” in the old group is an isolated case. Excluding this extreme case from the old group the upper limit would be 26 as compared with 25 in the new group.
It may be stated, as was stated in the study of 1929, that these data indicate this to be a problem dealing largely with adolescent girls. Only 22 of the 164 girls (13.4 per cent) were over 21 years of age at the time of their confinement.
The correlation (Pearson “r”) between age and intelligence is not high enough in either group to be very significant. There is only a fractional difference between the two groups in their coefficients of correlation. For the old group the coefficient is ? .210 zt .069 and for the new group it is ? .212 ? .073.
Summary
1. The average intelligence of the two groups of unmarried mothers is very similar. The median I. Q. for each of the two groups as well as for the two groups combined is 76. The mean I. Q. for the old group is 77.09, for the new group it is 79.07, and for the two groups combined it is 78.16.
2. The classification of intelligence according to mental levels shows that the old group ranges from normals to imbeciles, while the new group ranges from normals to morons. The two groups combined are shown to have the following classification: 20.5 per cent normals, 21.1 per cent dull normals, 31.1 borderliners, 25.4 per cent morons, and 1.9 per cent imbeciles.
3. The median age for each of the two groups and for the two groups combined is 18. The mean age for the old group is 18.37, and for the new group it is 18.59. For the two groups combined it is 18.49.
4. The coefficient of correlation between age and intelligence for the old group is ? .210 dr .069, and for the new group it is ? .212 ?.073.
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