introverts

“One of the most important forms of the child libido (energy of life that drives one to fulfill desires) occupation is fantasy making. The child’s world is one of imaginary and make-believe where he can create for himself satisfaction and enjoyment which the world of reality so often denies. As a child grows and the real demands of life are made upon him it becomes increasingly necessary that his libido be taken away from his fantastic world and used for the required adaptation to reality needed by his age and condition, until finally the adult freedom of the whole libido is necessary to meet the biological and cultural demands of life.
Instead of thus employing the libido in the real world, however, certain people never relinquish the seeking for satisfaction in the shadowy world of fantasy and even though they make certain attempts at adaptation they are halted and discouraged by every difficulty and obstacle in the path of life and are easily pulled back into their inner psychic world. This condition is called a state of introversion. It is concerned with the past and reminiscence which belong thereto. Situations and experiences which should have been completed and finished long ago are still dwelt upon and lived with. Images and matters which were once important but which normally have no significance for their later age are still actively influencing their present lives. The nature and character of these fantasy products are legion, and are easily recognized in the emotional attitudes and pretensions, the childish illusions and exaggerations, the prejudices and inconsistencies which people express in manifold forms. The actual situation is inadequately faced; small matters are reacted towards I an exaggerated manner; or else a frivolous attitude is maintained where real seriousness is demanded. In other words there is clearly manifest an inadequate psychic adaptation towards reality which is quite to be expected from the child, but which is very discordant in the adult.
The introvert…reacts to stimuli thinking and tends to withdraw from the object to think it over and weigh matters. For him action is difficult, uncertain and delayed. He cannot make an immediate and direct contact with the object because between his feelings and the object is his ego. An extreme example of this is in Hamlet ‘all sicklied o’er with the pale cast of thought,’ he broods, meditates and is often moody. If the introvert has had intellectual training and development he substitutes for his difficulty in activity and quick adjustment to the changing conditions of life, the creation of theories, philosophies and logical reasoning about things and seek to adapt himself mentally-his trouble comes in putting these ideas into practical application. This does not mean he is without feelings-one class of introvert is often called the emotional type-but his feeling is undifferentiated, and he reveals and inadequate emotional reaction and valuation. His emotions when aroused frequently show underdeveloped character so that it is not surprising to find highly cultivated introverts acting in a childish and infantile manner with deep moods of depression.”

Dr. Beatrice M. Hinkle, An Outline of Psychoanalysis.

not completly accurate but close enough