Nope, haunting of hillhouse is an old novel, like 1956 I wanna say. It was adapted for a movie sometime in the last decade, but is unrelated to the two film adaptations of the house on haunted hill Basically, scientist wants to conduct a study on the nature of fear, and who better to scare than the sleep deprived? So he advertises it as a study on insomniacs to get a bunch of sleep deprived people into this creepy old house, well he tries to **** with em a little for his experiment, but the place actually IS haunted by some crazy dude who ran a sweatshop with a bunch of little kids working it, and his vengeful asshole spirit wanted one of the experimental subjects there (note, this ghost is the one that called this particular subject and asked her to come, as far as the doctor knew she was a volunteer who read his ad in the paper) because she was the child of one of the kids who escaped from him and blah blah blah.

I think it should go beyond just testing a breaking point, maybe seeing at what point fear is enough to make somebody REALLY lose it, like to the point of killing everyone. Maybe trying to discover the extent to which fear can be used to control people, like the researchers setting goals of things to get somebody to do by scaring them in just the right ways.

A vengeful psychopath is always a fun character to implement, maybe this isn't the first batch of subjects they've done this too, maybe one they thought had died was hiding out and is now trying to scare the researchers. Maybe kill them. Maybe he's so far gone he no longer knows WHAT he wants to do. Maybe he's even escaped and joined the research team with the intent of getting back at the rest of the group.