Naturally, movie trailers would prove important to the horror genre. Not only do horror movie trailers have to give individuals a taste of what the movie is about, but also provide a little bit of the frights to be found in the film as well. For this reason, horror movie trailers would become a bit of an art all their own.
Perhaps the best known trailer for a horror movie ever made was the teaser trailer for Psycho. In fact, it could well be the greatest movie trailer ever made. Written by James R. Allardice (who also wrote Alfred Hitchock's introductions on Alfred Hitchcock Presents), the trailer features Mr. Hitchcock's trademark humour, as well as one big fright. At nearly seven minutes in length, it was also one of the longer teaser trailers ever made.
A perfect example of a trailer that showed what to expect from a horror film was the original trailer to Hammer Films' version of Dracula (1958), under its American title Horror of Dracula. I rather suspect that the American trailer for Hammer's Dracula was rather shocking to Americans at the time, given that it showed rather more blood than most horror movie trailers did at the time and an undertone of sex that was pretty much unknown in American horror movies.
Sadly, the trailers for the early Universal horror films Dracula (1931) and Frankenstein (1931) have not survived. Fortunately, the trailer for The Wolf Man, made ten years later in 1941, has.
Movie trailers are not simply an American phenomenon, as they were also used in the United Kingdom to promote films as well. Indeed, the perfect example of a trailer that may have actually hurt a movie's chances with critics and audiences may well have been the original trailer for Peeping Tom (1960). Much like Psycho, released the same year, Peeping Tom is a horror with a good deal of psychological depth and complexity. And just as Psycho was directed by a respected auteur, Alfred Hitchcock, Peeping Tom was also directed by a respected auteur, Michael Powell. Both films would be controversial, but in the case of Peeping Tom it is arguable that its trailer made matters worse. A complex, sophisticated film, the trailer for Peeping Tom treated it as if it was a mere exploitation film.
While the trailer for Peeping Tom is bad because it totally misleads viewers as to the nature of the movie, other trailers are bad because they simply reveal too much. The trend towards spoilers in trailers started in the Seventies and has not really ever gone away. Indeed, a perfect example of this is the trailer for the film Black Christmas (1974). A poorly done, pre-Halloween slasher film, its trailer very nearly gives away the whole plot. And at nearly four minutes, the trailer is also much too long.
From the above examples, it would appear that creating a trailer for a horror movie is a bit of a balancing act. One must give the audience enough of fright that they want to see the movie, without misleading them as to the nature of the film or giving away too much. In many respects the teaser trailer for Psycho was nearly prefect in this regard. Sadly, it would seem the trailers for Peeping Tom and Black Christmas were not. Of course, it must also be pointed out that a good film can overcome a bad trailer. Peeping Tom is not regarded as a classic. On the other hand, a bad film probably not going to be helped by a good trailer. Even if the trailer for Black Christmas had not given away too much of the plot, the film would still be considered a bad film regardless.