The term "primal scene" describes a shocking, yet arousing childhood experience. According to Freud, it usually involves children seeing their parents having sex. The scene does not have to be real. It may be imagined or observed elsewhere.
Our entire existence is influenced by our reaction, as children, to the primal scene and by our ideas about the role we play in our parents' sexual activities and desires. Freud assumed that the primal scene shapes our relationships with parents and lovers and determines our sexual preferences. The experience of the primal scene is an essential building block in the development of the unconscious.
"Hans: When the horse in the bus fell down, it gave me such a fright, really!
Father: Why did it give you such a fright?
Hans: Because the horse went like this with its feet. (He lay down on the ground and showed me how it kicked about.) It gave me a fright because it made a row with its feet."
Freud conjectures that when the horses "made a row" with their hooves, it reminded Hans of the sounds his parents made during sex. The entire scene not only excited but frightened Hans. Excluded, he perceived it as an act of violence on the part of his father toward his mother.