Character Analysis
Not Marion
There's not a whole lot to Lila… except that she's not Marion. (In Psycho, being "not Marion" is a good thing.)
Marion's an interesting character. She's got depths. She seems professional and bland on the surface, but you know right from the start that she's running off at lunch to have quickie sex. When the rich client Cassidy asks her towards the beginning of the film if she's happy, she responds "Not inordinately," which is a psychologically fraught question. How unhappy does Marion think people are, usually? What's her own level of unhappiness?
And then, of course, Marion uncharacteristically steals a ton of money—a fact which both terrifies and, at moments, seems to delight her. Marion is unpredictable, volatile, and sexy. She is, as Norman demonstrates, worth watching.
But what about Lila? All there is to her character is that she wants to find the lost Marion. Why do we even need her there? What does Lila add?
Or Maybe Marion After All
It's true that Lila isn't necessary to the plot. But she serves an important purpose for Hitchcock. Without her, the second half of the film wouldn't have a blonde woman in it.
And no, we're not just being snide.
Hitchcock was obsessed with blonde women in distress. Icy blondes feature in many of his most famous films—in fact, they're so ubiquitous that they've gotten a collective identity as the "Hitchcock blonde."
Hitchcock famously said:
"Blondes make the best victims. They're like virgin snow that shows up the bloody footprints." (Source)
For Hitchcock, it's more suspenseful, more exciting, and sexier to have a blonde woman in danger. Norman attacking Sam is boring. Norman attacking Lila, on the other hand… that's what Hitchcock wants to see.
Lila, then, is there to be the Marion stand-in after Marion is already dead. You've got to have her there to say, "Mrs. Bates…" as she goes into the house, and then have Mrs. Bates (almost) get her. Hitchcock got rid of his leading actress, so he needs another one to play with.
Lila is a placeholder, rather like Norman's mother's corpse. There isn't much life in her, but an obsessive, creepy guy can't do without her—and when we say "obsessive, creepy guy" we're referring to Hitchcock, not Norman Bates.
Lila Crane's Timeline