Trivia: At various points in the film, Jack Nicholson flicks his eyes to the camera, often only for a few frames, frequently hard to catch. It's deliberate - in one clip of behind the scenes footage Kubrick lies under him while setting up a scene, and specifically tells him to look down to the camera when filming. But there's no specific answer as to why - genre-defying, or to make the audience feel more threatened, or to make the viewers feel like the ghosts he sees. Hard to unsee though.