This article compares how physical aggression in children comes from their genes and the environment in which they grow up. On the other hand, social aggression, such as spreading rumors or ignoring other children, has more to do with environmental factors. In this article, scientists researched 400 pairs of 7 year old twins and assessed the genetic and environmental effects on children's physical and social aggression. They found that physical aggression in children tends to show itself more when children have physically aggressive friends. Genes were not associated with children's social aggression and instead based on the the friendship circles children were in.
I agree and relate to this article because as a kid growing up, and as an assistant teaching for kindergarteners, I notice that children tend to go with the group behavior. they may be raised a certain way at home and have certain genetics, however social bullying and aggression comes from being around friends who encourage it and do the same, so that they feel like they belong.