We combine several persons into one, selecting as a rule the most striking features of every one of them. We may see a dream character with the eyes of one person, the nose of another and the beard of a third one.
Freud having made one proposal to two different men, Dr. M. and his brother, the former having a beard and the latter being clean shaven and suffering from hip trouble, combined them in a dream in a figure which looked like Dr. M., but was beardless and limped.
One of Ferenczi's patients dreamt of a monster with the head of a physician, the body of a horse and draped in a nightgown.
Silberer dreamt of an animal which had the head of a tiger and the body of a horse.
This is a process similar to the one which in the infancy of the race gave birth to strange composite gods and mythological creatures like the Assyrian bull a combination of man's intelligence, the bull's strength and the bird's power of flight, the various Egyptian deities in whom the process was reversed, for so many had the heads of animals and the bodies of men, the satyrs and syrens, combining respectively man and goat, woman and fish, Pegasus, the winged horse, etc.
Finally, dream life is simplified through the symbolic representation of human beings or inanimate things.
In symbolization, one striking characteristic of some complicated object is isolated from the others and some other object with only one characteristic substituted for it. Slang is made up of such symbolizations. Think of the expression "bats in the belfry," in which the complicated human head is replaced by an architectural detail much simpler in character and occupying in an edifice the same position which the head occupies in human anatomy. Then, instead of describing absurd ideas, of a sinister colouring, without definite direction, we simply visualize queer creatures, half bird and half mouse, flitting about blindly.
Instead of explaining that the central figure of the christian religion is a godlike creature who died crucified, we select the most striking detail of the Passion, the cross, which to the initiated and uninitiated alike signifies christianity. In many cases we do not even represent the cross as that instrument of torture really looked but we simplify it, we symbolize it, by using a conventional design in which the proportion between the cross pieces has been entirely disregarded.