Mr. porter believes that aggression is an unlearned behavior characteristic of all children. he obviously believes that aggression is a (n) :

The answer is "instinct".

It is basic to decide the degree to which a specific behavior can be named as an instinct. Aggression is a widespread and unavoidable reaction in people, however so is strolling. In any case, walking isn't viewed as an intuition; when a kid begins to demonstrate forceful conduct they have learned numerous different practices, whereby a considerable lot of them are not instinctual. This infers the ubiquity and predominant of a particular conduct isn't an economical purpose behind thinking about it as an instinct.