Horror/Slasher

P-s-y-c-h-o spells horror.

Okay, if you spell "horror" that way on a test, you'll get points off. But in the history of horror film, Psycho is everything, plus the kitchen sink (and the shower stall).

Hitchcock made Psycho with a relatively cheap budget (only $800,000, or about $6.3 million in 2015 dollars), because he wanted it to look like an exploitation schlock horror film in the vein of low budget thrillers like The Creature From the Black Lagoon (1954).

Hitchcock also included gothic horror touches looking back to stories like Dracula. Norman's creepy, looming house, the muddy swamp, and of course Norman's mother's gaping skull—those are all touches that could have been used in a horror story going back to just about the beginning of film.

But Psycho also broke with the past in important ways. As critic Owen Glieberman writes:

"Before Psycho, horror movies were "monster" movies. They were fantasies in which men battled supernatural creatures – or turned into them. [But in Psycho] here was a horror film in which the "monster" lived inside the head of one man—poor, schmucky Norman Bates, the mamma's boy with a black secret." (Source)

Psycho changed horror to make it psychological. The terrifying evil wasn't out there, in some monstrous alien or mystical critter. It was inside the brain. Monster horror survived (just check out Alien) but it was joined by a whole slew of films in which the scary thing is just some human killer who does horrible things.

Hitchcock made horror into a genre that appreciated that the scariest thing might just be that nice boy behind the desk.