Various photography lighting guides state that when light is positioned above a face it looks natural, but when positioned below a person it looks unnatural or even "creepy".
This is sometimes used deliberately in movies to evoke fear.
The universal principles of design say that this is because we evolved on planet earth with a single sun, which is always above us.
But there are plenty of natural situations where light could come from under us. Such as being reflected off the ground, snow, or water, or just sitting around a warm campfire.
I'm just curious if there are any known psychological reasons why lighting under a face might look unnatural or "creepy"? Or could it be that it's such a staple of horror movies that we're primed to perceive it that way?