Genre has always had an effect on the success of a film. If a film does not appeal to a large number of people, it is doubtful that they will spend their money to go see it. Genres often go through phases of popularity, as the period in which a film is released also affects its success. This is obvious after the events of September 11th, in that many movies were postponed or cancelled because they dealt with terrorism and the studios believed that they would not draw in audiences. Some genres, however, never seem to disappear or lose popularity; they have drawn in audiences throughout the history of film. One such genre is the horror film, which has seemingly maintained popularity from 1920 with the release of The Cabinet of Dr. Caligari to the present day. It has definitely gone through various stages of evolution, as is obvious when comparing a Universal monster movie of the 1930s to a contemporary slasher horror film of today. There are some aspects, however, that are constantly found in horror films, no matter the period or sub-genre. The goal of good horror films is to scare and disturb the viewer, be it a physical or emotionally focused attack, but they also tend to confront the ideas of human vulnerability and often reflect societal problems of the period. Two films that espouse such ideals are Night of the Living Dead (1968) by George Romero and The People Under the Stairs (1991) by Wes Craven. Both of these films challenged and altered the perception of the horror genre in different ways, but each nonetheless kept certain aspects of the genre intact such as reflecting the society of the time and in being created to scare the viewer.
Horror films have specific genre conventions that distinctly categorize them into the horror genre. Horror stories, as well as films, have been called a "mirror in which we can find ourselves, but only if we are willing to seek what we have found there, only if we confront our desire to be lost in horror and darkness" (Kawin, 237).