“Retest Changes in the Iq in Certain Superior Schools”, 1940 ():
In order to provide further data for understanding the effect of schooling upon the IQ, we analyzed the Binet retest records that have been accumulated in the files of 3 of the best-known private schools in and around New York City—Ethical Culture, Horace Mann, and Lincoln.
These records have been accumulated over the past 20-odd years. They represent retest data on a total of about 3,000 children. Over 1,100 of these retests had been given after an interval of at least 2.5 years, and these records will be the ones on which most of our analysis will be based.
In two of the schools the average gain in IQ was negligible, while in the third it was appreciable, amounting to over 6 points. [Flynn effect?]
The data suggested no satisfactory explanation for the differences reported, and it remains something of a mystery to the authors, who have to content themselves at present with proffering a plausible, though unsupported, hypothesis to account for it.
See Also:
Are correlations between cognitive abilities highest in low-IQ groups during childhood?
Developing talents: A longitudinal examination of intellectual ability and academic achievement
Influence of young adult cognitive ability and additional education on later-life cognition
Childhood Physical and Mental Health Records of Historical Geniuses
On the adequacy of standardized tests administered to extreme norm groups