Birth order and self-concept in adolescence.

The effect of birth order on self-concept was examined in a sample of adolescent boys and girls. Based upon self-theory, which suggests that the two main processes of self-concept formation (e.g., reflected appraisals and social comparisons) are affected by the power and role relationships associated with ordinal position in the family, several hypotheses were tested: (1) The self-evaluations of only and oldest children are more positive than those of younger siblings; (2) middle-borns have the lowest self-evaluations; (3) these relationships are affected by the sex and spacing of nearest sibling; and (4) the self-conceptions of oldest and only children are more similar to those of their parents than the self-conceptions of younger siblings and their parents. Using analysis of variance and several different measures of self-evaluation, very little support was found for any of these hypotheses. The strongest support was found for the hypothesis on middle-borns, but even these relationships were not large. Several explanations are offered for these weak and inconsistent findings.