Observations drawn from different sources suggest that as compared with later-born individuals, the 1st born participates in a more intense mothering relationship, has a shorter duration of interaction with siblings, turns to his parents in the absence of other role models, is exposed to greater parental expectations regarding responsibility and achievement, develops a harsher superego, and is more inclined to choose occupations involving a parent-surrogate role--in short, that he is more adult oriented than later borns. It was hypothesized, therefore, that 1st borns would demonstrate greater internalization of parental norms and values. Results supported the hypothesis for inhibitory-disciplinarian behaviors but not for emotionally supportive-rewarding behaviors. Implications for processes of identification and super-ego development are considered. (31 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)