Parents often talk about the differences between their first-, middle- and last-born children and say these differences must be inbuilt as they treated their children the same. However, parents often forget that the experiences of being an older, middle or younger sibling can be quite different. Parents are often very attentive to their first-born child and follow rules such as being strict about how many sweets they allow their child to eat but by the time they have a second child they become more relaxed about the rules. When parents have a second child, they often expect their first-born to be more responsible and they often have to grow-up quicker than later-born children. The first-born child also has to deal with the shift from having their parents’ undivided attention to having to share it with a sibling. As a result, firstborns are viewed as responsible, conscientious, cautious and achievement-orientated. Parents tend to be more relaxed in their parenting style after their first-born child and later-born children are often more liberal and rebellious. Middle children suffer from being neither the oldest nor the youngest child in the family, which can lead to identity problems. They may wonder where they fit in and this can lead them to be sociable, people-pleasers with a tendency to rebelliousness. The last-born child is often babied as parents are less keen for them to grow up quickly. This may lead the youngest child to be less responsible, rebellious and sociable.
What does the research say about birth order effects?
Sulloway (1996) in the book ‘Born to Rebel’ discussed the findings of numerous studies, which show that first-borns are more conscientious but less agreeable and less open to new experiences than later-borns. However, when spouses are asked to rate their partners on personality characteristics, birth order seems to have no significant impact (Jefferson et al. 1998). On the other hand, there is clear evidence that first-born children achieve more both in terms of grades at school and long-term financial success (Paulhus et al. 1999, Zajonc and Markus, 1975).
Sulloway (1996) found that later-born children are more agreeable, liberal and rebellious than first-borns. However, birth order effects seem to have a greater impact on intellectual development than personality. Parents tend to be less attentive to later-born children as they have to divide their attention and this may make them less achievement-orientated (Paulhus et al. 1999).
Unlike children with siblings, only children do not have to compete for their parents’ attention. This has its benefits and downsides. Parents have the time to invest all their resources in one child; however, there can be a burden of expectation on an only child. As a result, only children are often viewed as conscientious and mature for their age. They often have close relationships with their parents and are keen not to disappoint, which can lead to perfectionist tendencies.
When children have to live with step-siblings as a result of separation, divorce and remarriage, children have to adapt their behaviour. For example a first-born child may end up having an older step-sibling in a blended family and cannot maintain their position as the leader. However, children do not tend to change their personality after 5-years-old so they will usually keep the personality characteristics related to their birth order even if they have to change their behaviour. On the other hand, a 3-year-old first-born child may adopt some personality characteristics of a later-born child if they start living with older step-siblings.