Abstract
One hundred eighty-one of 2341 4-year-olds had I.Q. below 70 (7.7%). 133 of 181 had I.Q. between 60 and 69 (73.5%). Of these 133, 94 Negro children were studied, on whom there was complete information available for analysis on maternal socio-environmental, prenatal history, pregnancy, labor, and delivery records; examinations at birth, 4 months, 8 months; 1, 3, and 4 years. As controls, 94 Negro children matched as to birthdate and sex were used with an I.Q. above 90 on the 4 year examination.
The study children showed a higher incidence of low birth weight, delay in motor development at 1 year and delayed speech development at 3 years.
The mothers of these children had the following characteristics namely: a higher incidence of teenage pregnancy, low education, large family size, closer sibship and a low socio-economic index.
At 7 years of age of the 87 available children 6 (6.9%) still had an I.Q. below 70. 43 (50%) showed a gain to the 80–109 level, 34 (39%) showed a rise to the 70–79 level. Of the 74 available controls 13 (17.5%) dropped to 80–89 I.Q. level and 2 (2.7%) to the 70–79 level, while the remainder showed minimal changes in I.Q. points within the normal range. A further analysis of preschool and school activities, the I.Q. of siblings and the changes in socio-environment suggest that the availability of stimuli outside the home had contributed to the development to their genetic potential of the children in whom there was a significant increase in I.Q. points.
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Ting, R., Scott, T., Atkins, T. et al. What happened to I.Q. between four year and seven year in a selected collaborative project population. Pediatr Res 5, 376 (1971). https://doi.org/10.1203/00006450-197108000-00023
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DOI: https://doi.org/10.1203/00006450-197108000-00023