Abstract
There is an extensive literature on the relationship between birth order and psychological traits, but no previous study has investigated the influence of ordinal position on personality development within adoptive siblings. Such a design is important because it effectively separates the effects of biological birth order and rearing order. Here we report data from two adoption cohorts in which subjects were biological first-borns reared in various ordinal positions. Data were analyzed with reference to Sulloway's (1996) evolutionarily based sibling rivalry theory of birth order effects. Between- and within-family analyses indicated that rearing order's influence on personality was very weak. The only clear difference was for conscientiousness, on which first-reared siblings scored higher. We draw possible implications for Sulloway's theory and speculate upon an alternative, prenatal biological process that may produce birth order differences.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
