Children often first learn about loyalty and responsibility by interacting with their siblings. Not many children will watch a younger brother or sister being taunted by playmates without rising to the defense. Children also become practiced on competitiveness and domination by battling with older and younger children in the family. Even this tiresome bickering seems to yield desirable side effects in terms of a child’s personality. She learns how to moderate her feelings of jealousy and share an adult’s attention, how to be flexible and to compromise in play all necessary skills for a school bound child.
The sex of the child’s siblings and her birth order in the family also affect personality. Researchers have observed that girls with brothers, particularly older brothers, will often become more ambitious and aggressive than girls with sisters. Boys with older sisters tend to be less aggressive than boys with older sisters tend to be less aggressive than boys with older brothers. And all children who grow up in the family with older brothers tend to be more physically active.
Studies have also shown that the oldest child in the family is likely to excel in areas deemed most important by the parents-getting good grades in school, for example- and may work harder to solve problems. This may be due to the exclusive relationship the child has with her parents until a sibling is born, and to the high expectations the parents typically have for their firstborn child. Later born children whose parents are more experienced and usually more relaxed in child rearing, tend to adopt less demanding standards for them selves. A family’s younger children tend to be less cautious than firstborns, as well.