Occasional observers of horror movies have a nasty habit of asking why it is that there is always some poor misguided soul who opens the door to the cellar or to the attic or to the crypt when it's quite clear that no sane person would even consider it.
Like the panic stricken populace of 'The War of the Worlds' and countless other 1950s invasion movies, the victims are there to provide the human ground over which monster and expert, threat and defender, disordering and ordering impulses can battle it out. Second-class citizens of the genre, they are narratively indispensable because physically entirely disposable. We are only really involved with them in the momentary tension of their capture or demise.
Contemporary audiences, other than those making a deliberate historical leap, would find, say, the 1931 'Dracula' impossibly slow.
Along with supernature and science, there is one other major source of horror movies disorder: the human psyche, most commonly homicidal psychosis. Unlike 'mad' scientists, horror-movies madmen are not visionary obsessives, glorifying in scientific reason as they single-mindedly purse their researches. They are, rather, victims of overpowering impulses that well up from within; monsters brought forth by the sleep of reason, not by its attractions.
Typical horror movies of the 1930s were often given a period setting in what looked like a kind of stylized 19th century... the sense of 'elsewhen', of distance, lent to many of these movies by their settings. They exist, as it were, in a 19th century of the mind.
In a Western or a thriller there is often room for reflection upon the coercive necessities; even, occasionally, some attempt to pose other possibilities. In the horror movies there is finally a Hobbesian state of nature: 'continual fear and danger of violent death; and the life of man, solitary, poor, nasty, brutish, and short'.
In 'Play Misty For Me', its inexplicably assertive knife-woman nearly manages the impossible task of slaughtering Clint Eastwood.
