The sense of competition is inherent to all humans as we want to be appreciated by other people. The strive to competition is especially acute in the childhood. It comes as soon as little kids realize that their social environment or even parents will love them on certain conditions. And sibling rivalry usually emerges from a natural desire to be praised and acknowledged by the most loved ones.
Hostility towards one’s own siblings does not appear out of the thin air. The primary causes of such behavior are the uneven distribution of parents’ attention, and ill-considered upbringing which puts a child in the center of everything. Babies do not come “programmed” to fight for every minute of parents’ attention, therefore education is a core factor which influences the behavior of children.
One of the probable ways how parents encourage their children to compete with each other is a constant comparison with the other children. Adults impose the feeling that love comes as a bonus for a good behavior and other children frequently appear better in this respect. Comments of the kind “See how nice your sister/ brother behaves?” assure children that parents will never acknowledge them being as good as their siblings.
Sometimes parents regularly pay more attention to one of the siblings because they feel that one of the kids has more chances to become successful. “This kid was destined for a great future from the very beginning”, they say and ignore the kid who does not show any extraordinary abilities as compared to their sibling.