On Aggression

On Aggression (1966) is a book by ethologist Konrad Lorenz written in 1963. As he writes in the prologue, "the subject of this book is aggression, that is to say the fighting instinct in beast and man which is directed against members of the same species." (Page 3)

According to Lorenz, animals, particularly males, are biologically programmed to fight over resources. This behavior must be considered part of natural selection, as aggression leading to death or serious injury may eventually lead to extinction unless it has such a role.

However, Lorenz does not state that aggressive behaviors are in any way more powerful, prevalent, or intense than more peaceful behaviors such as mating rituals. Rather, he negates the categorization of aggression as "contrary" to "positive" instincts like love, depicting it as a founding basis of other instincts and its role in animal communication.

Additionally, the book addresses behavior in humans, including discussion of a "hydraulic" model of emotional or instinctive pressures and their release, shared by Freud, and the abnormality of intraspecies violence and killing. His 'hydraulic' model, of aggression as a force that builds relentlessly without cause unless released, remains less popular than a model in which aggression is a response to frustrated desires and aims.