The Effect of Pre-School Attendance upon the IQ

This study of the effect of pre-school at tendance upon the IQ is part of a larger in vestigation on the growth of intelligence of children from two to fourteen years of age.1 In the portion of the study discussed here, comparisons are made within groups of chil dren all of whom have been enrolled in the pre-school laboratories. In some instances a given child is paired with himself under different periods of pre-school attendance and non-attendance, and in other instances different groups of children are compared. Individual intelligence examinations were given to about 600 children attending the pre-school laboratories of the Iowa Child Welfare Research Station from 1921 to 1932. The Kuhlmann revision of the Binet scale was used, for the most part, up to three and one-half years of age and the Stanford re vision for the older ages. In the earlier years of the laboratories the Stanford re vision was used for the younger ages also. More than twenty persons made the examina tions; all were experienced testers. No at tempt was made to assign the same child to a given examiner for retest. Since the mean IQ obtained on first tests on the two scales was practically the same for three-year-old children (110.8 with a standard deviation of 17.4 for seventy-five children on the Kuhl mann scale and 111.4 with a standard devia tion of 15.2 for ninety-seven children on the Stanford revision), the IQis obtained on the two scales have not been treated sepa rately. Retests were given at intervals of about six months during the pre-school ages, and were continued yearly up to the age of fourteen years, six months, when the chil dren were enrolled in the University Elemen tary and High Schools. INCREASE IN IQ ON RE-EXAMINAT I ON