Aggression is a natural tendency in human and animal species. We are naturally motivated to be aggressive to defend ourselves against external dangers. Some people are more aggressive than others are, because there are so many factors that affect how we express our aggression. There are certain individuals who can be easily triggered into a aggressiveness for the slightest provocation, while others may have high degree of self control and they may turn their aggressiveness into alternative channels or they are so much self-controlled that they may turn their aggressiveness against themselves.
Psychologists have tried to explain aggression through different theories. Some scientists look at aggression from an evolutionary perspective and explain it as an instinct or a pattern of the action that has developed throughout human evolution. We can find a clear example of aggression in animals when their territory is invaded by an enemy or by a rival. In animals, attack on offsprings elicits a strong aggressive action which is a natural tendency to protect the species. Sigmund Freud, the founder of psychoanalysis, discussed aggression as a human orientation which originated from a deep instinct he called "Thanatos." Thanatos, according to the Freudian theory, is the death instinct. This is an essential part of all human psychological structure. Another psychoanalytic psychologist, Alfred Adler, regarded aggression as a display of the will to power. Adler focused his attention on the inferiority feeling in humans and their desires to overcome their weakness by power and control of others. Some psychologists linked aggression to frustration and explain it by a response to a frustrating situation. The social learning theorists view aggressive acts as learned behaviour. This theory assumes that we become aggressive through observation, imitation and modelling of our behaviour on what others are doing. Such behavioral theory adopts the view that any behaviour that is rewarded will become part of our repertoire of future behaviour. It is possible that throughout our evolutionary history, we have learned that aggressive behaviour succeeds in protecting ourselves, our loved ones, and it also realise our aims and help us to achieve our desires and aims. However, human moral development has made the humankind recognise that aggressiveness would lead to gains for one party and loss for others. For a more ethical and fair game, both parties would win if they resolve their conflicts without falling back on aggression.