Externalizing behaviors include aggression and conduct problems. Aggression is generally defined as a behavioral act that results in harming or hurting others. Because aggressive behavior and its treatment vary greatly according to the intentions and conditions surrounding the aggression, it is typically categorized according to different types. Aggression can be physical or verbal; relational, proactive, or reactive; and overt or covert. The literature often differentiates between proactive and reactive aggression because such a framework allows for the explanation and description of aggression (Dodge, Lochman, Harnish, Bates, & Pettit, 1997). Children engaging in proactive aggression typically use aggression to meet a goal. When the aggressive behavior yields the desired reward, the child is more likely to engage in proactive aggression the next time s/he intends to meet a goal. Conversely, reactively aggressive children do not seek to meet goals through their aggression. Instead, these children react quickly and impulsively to perceived or actual threats and can become intensely irritated.