Birth Order of Children in Families

The effect of birth order on personality, behavior, and achievements has been a controversial issue, with popular books describing the precise personality traits for firstborns, middle borns, and last borns, while scholars disagree about whether there is empirical evidence for differences. Recently, Frank Sulloway reviewed the research and concluded that whereas firstborns identify with power and authority and are assertive, dominant, and ambitious, younger siblings are more likely to question the status quo and become revolutionaries.

Birth order effects are complicated by the sex of the children, the number of children, and the age differences between them. There are also potential differences between one's actual birth order in the family and psychological birth order based on such factors as the death of siblings and the presence ...