Birth Order and Familial Sentiment Middleborns are Different

Effects of birth order on several aspects of family relations and self-identity were examined in three studies. In Study 1, first and lastborn undergraduates were more likely than middleborns to refer to kinship in characterizing themselves. In Study 2, subjects were asked to whom they would turn under two scenarios of duress. First and lastborns were more likely to nominate parents, whereas middleborns were much more likely than other respondents to nominate siblings. In Study 3, analyses of historical archives and of an Internet questionnaire indicated that genealogical research attracts many more firstborns and many fewer middleborns than expected by chance. In all three studies, first and lastborns were much more likely than middleborns to nominate their mothers as the person to whom they felt closest. These substantial effects support Sulloway’s claim that birth orders constitute significant family “niches,” which differ with respect to the perceived dependability of parental investment and therefore also differ in the social orientations that they engender.