Gory stuff can be shocking but it doesn’t really scare me. I’d say the kind of stuff that gets under my skin is the unknown. You hear a knock behind a wall and you don’t know what it is. Is there something there or not?

The less people know about 'Paranormal Activity,' the more they enjoy it.

Because of the way we let the actors improvise, it feels like you're watching people react rather than actors reading lines - so I think that's always going to be something I like.

By trade, I am a software programmer, so I never really had any experience with movies before. I started out with 'Paranormal Activity.

Even when I was making the first 'Paranormal Activity,' I didn't tell anyone I was making it, not my friends or neighbors or co-workers. I just kind of found that there was nothing to gain by announcing to the world that you're doing something.

For a found-footage-style movie, there's a definite advantage in using unknowns, because it helps sell the illusion that it's real. A known actor would get in the way of the suspension of disbelief.

Even if you look at the 'Paranormal Activity' movies, at the end of the movie things get really crazy and nutty, but they all start in a very mundane situation that people can relate to, and that's also to some degree what we tried to do in 'Chernobyl Diaries.