Aggression refers to behavior between members of the same species that is intended to cause humiliation, pain, or harm.

Ferguson and Beaver defined aggressive behavior as "Behavior which is intended to increase the social dominance of the organism relative to the dominance position of other organisms”

Aggression takes a variety of forms among humans and can be physical, mental, or verbal.

There are two types of aggression - hostile, affective aggression and instrumental, predatory, or goal-oriented aggression.