Norman Bates is the cold-blooded serial killer in the Psycho films. He loses his sanity and went insane due to the manipulation and mental abuse of his mother Norma Bates (nee Spool), and was driven over the edge when she dated a man named Chet Rudolph; he killed them both in revenge, only to develop a split personality disorder, with "Mother" being his other personality. He killed three women and one man until being taken to an asylum in 1960; he made a full recovery and was released, but later lost his sanity again and continued killing people until finally resisting his mother's control. Norman lived the rest of his life normally afterward.
Both the novel and film explain that Bates suffered severe abuse as a child at the hands of his mother, Norma, who preaches to him that sex is evil and that women, excluding herself, are whores. The two of them live alone together in an unhealthy state of emotional dependence after the death of Norman's father. When Norman was a teenager, his mother takes a lover, making him insanely jealous. Bates then kills them both and preserves his mother's corpse. Bates develops, assuming his mother's personality, repressing her death as a way to escape the guilt of murdering her. He inherits his mother's house, where he keeps her corpse, and the family in Fairvale, California.
Bloch sums up Bates' multiple personalities in his stylistic form of:
- "Norman", a child dependent on his mother;
- "Norma", a possessive mother who kills anyone who threatens the illusion of her existence;
- "Normal", a (barely) functional adult who goes through the motions of day-to-day life.
Bates is finally arrested after he murders a young woman named Mary Crane (called Marion Crane in the film) and Milton Arbogast, a private investigator sent to look for her. Bates is declared insane and sent to an institution, where the "mother" personality completely takes hold; he essentially becomes his mother.