Flashback to a different era

Guess the year these conclusions were published

The authors stress the importance of the fact that sex differences in variability and specific mental functions do occur. They suggest that the superior rating of the girls in Mrs. Pressey's study is due to the fact that girls' development is accelerated from one to two years during the period between 9 and 15; and that the superior rating of the high school boys in their own study is due to the fact of selection—that more dull girls than dull boys probably remain in high school to graduate.