They tend to do poorly in school, have little positive reinforcement, and may come from a dysfunctional family. Bullies frequently hang out with other bullies, which further reinforces their negative behavior. But don't confuse bullies with aggressive children, warns Dr. Bennett. Aggressive children may seem out of control because they act without thinking. Bullies exhibit self control and usually pick their victims and plan their attacks.
Bullies lack empathy and have trouble understanding the pain of others.
In fact, they may enjoy inflicting pain. And contrary to popular thinking, not all bullies are boys. In fact, until the latter grade school years, girls are more likely to be bullies than boys because of their faster development. However, girls tend to bully through verbal means or isolation, rather than physical intimidation. Bullies tend to pick victims who are easy targets.