You have two groups of people, Group A and Group B. You put Group A up in a "real" haunted house, meaning a place that actually has a history of rumors about paranormal activity occurring there. You do not inform the members of Group A that the house is supposed to be haunted; for the whole duration of the experiment, you make up some other pretext for them being there, but whatever it is, it should involve recording their activities. Unlike Dr. Marrow in the movie, you make a solid effort not to put the group on edge.
Now for Group B, you put them up in a "fake" haunted house, meaning a place that has had no supernatural history or sordid past. A brand-new house, built far away from any place that might be haunted, would be best. But with Group B, you tell them it is haunted, make up some spooky story about the house's history, and, like Group A, you ask them to record their activities throughout their stay.
So you have both groups staying in their respective houses for a week, with each member of each group making a diary of daily events, and at the end you have a little conference with each group where they talk about their experience. By the end of the week, which group will, in their personal logs or group discussion, report paranormal experiences? Will it be the group that has no idea what kind of place they're staying in, but where others have sworn they had a paranormal encounter? Or will it be the group in a totally innocent place, but who will be more inclined to jump at shadows and small noises?
My hypothesis is that Group B would be more likely to report supernatural experiences, though I wouldn't be too surprised if Group A reported them as well. Since I do believe in God, Jesus Christ, and the devil, and that our spirits live on after we die, I think it's possible that many supernatural reports are real. But I also recognize that some people will tell a good whopper now and again (especially if there is money involved) and that sometimes people get spooked over nothing.
One possible flaw in this experiment is that if Group A doesn't know they are supposed to expect and report paranormal encounters, each individual person may not tell of any such experience they had, if they think no-one will believe them. I know if I had a genuine experience with persons or powers from beyond, but no objective proof of that experience, I wouldn't go out and publish a book about it or make a movie on it, or even write about it here. Unless I was specifically instructed by God to spread it far and wide, I wouldn't share a supernatural experience with anyone who I didn't think would understand. I believe that such things are personal and sacred, and tossing them out to the masses is casting pearls before swine, figuratively speaking, and doesn't do anyone any good.