Most people feel anger and aggression sometimes—including children. Adults tend to have better control over their behavior when these feelings arise. Children, however, may turn their energy toward violent behavior such as kicking, biting, or hitting.  In some cases, kids lash out because they're frustrated by a problem that's too big for them. They haven't yet learned how to control their impulses, or work out conflicts in socially acceptable ways. Aggression doesn't happen because we're programmed to respond to the world with hostility. We all have the capacity to behave aggressively. Whether or not we do it depends on how we perceive the world. Aggressive tendencies are shaped by environmental conditions -- the pressures, threats, opportunities, and consequences that children experience. By tweaking these conditions, we can improve behavior and change the course of development.