permitting development in a more "mature" environment. The only child suffers from the lack of opportunity to teach younger siblings-a handicap affecting last-born children, too.
Thus, some of the decline in SAT scores may be attributed to a steady fall in the percentage of first children born between 1947 and 1962 (from 42 percent to 27 percent), resulting in fewer children taking the SAT who have the intellectual advantages of being firstborn. The proportion of first children has been...