Order of Birth, Parent-Age, and Intelligence

Abstract

When limited to siblings the results appear to show a definite tendency of intelligence to increase with the order of birth as far as the eighth born child. A check on the findings has been carried out by Miss Steckel of Sioux City, Iowa, in the testing of a normal population of twenty thousand school children, cases being drawn from 2,712 families, the study being limited to siblings. The results confirm those of the study of the Institute children, the