Staying within the framework of psychoanalytic concepts and terminology, which are broad enough for the expression of the pertinent problems, Bowlby justly considers the child's relationship to his first object, the mother, as an essential, vital part of his development. He rightly considers separation from mother as one of the basic danger situations, and his and Robertson's observations bring beautiful illustrations of it.

To the danger of separation from the mother, the child responds with various gradations of anxiety. The child responds to the actual, temporary, or permanent loss of the mother, among other reactions, with various shades of depression.