In psychology and other social and behavioral sciences, aggression refers to behavior that is intended to cause harm or pain. Aggression can be physical or verbal, and behavior is classified as aggression even if it does not actually succeed in causing harm or pain. Behavior that accidentally causes harm or pain is not aggression. Property damage and other destructive behavior may also fall under the definition of aggression. Aggression is a complex phenomenon that is composed of a number of more specific types of behavior. Aggression is directed to and often originates from outside stimuli, but has a very distinct internal character. Using various techniques and experiments, scientists have been able to explore the biology and genetics of aggression, as well as social or environmental factors.