Sex differences in the course of personality development: a meta-analysis.

Size and stability of sex differences in personality growth throughout adolescence and adulthood are examined. Studies using the Washington University Sentence Completion Test of ego development served as the primary source data. Sixty-five studies (encompassing more than 9,000 Ss) generated 113 independent effect sizes. Sex differences in ego development were moderately large among junior and senior high-school students (female advantage), declined significantly among college-age adults, and disappeared entirely among older men and women. Sex differences were relatively stable during early and middle adolescence. The greater maturity displayed by adolescent girls is not an artifact of superior verbal abilities. Sex differences in ego development were more than twice the magnitude of differences in vocabulary skills (Hyde & Linn, 1988). The present findings, together with findings from reviews of sex differences in moral judgment, aggression, and empathy, suggest that adolescent girls achieve developmental milestones earlier than boys, a difference that declines with age.