This is one of those films about which it is best to know nothing in advance. If complete ignorance is not feasible (one knows after all that one is going to see a movie), it were better not to know that it is both genuinely scary and altogether unfamiliar in texture. To be told in advance that a movie is eerie is a reliable recipe for disappointment, so I won't tell you that.
Instead I will tell you something about my house tonight, something that was true only after I returned from the theater. There are a lot more shadows in each room than I remember, and the sound of the dryer balls tumbling in a machine downstairs seems, dare I say it, vaguely malevolent. The fact that, no matter where I stand or in what direction I look, I can't see around corners or down darkened halls or behind me, is something that I am acutely aware at this moment. I will also tell you that, years ago, I forbade my adolescent daughter to play with an Ouija board. I am suddenly very glad that I did so. Nothing in what I have said should be taken as any indication of what you will experience should you go to see Paranormal Activity.
Since I am not going to tell you anything about this movie, I will write instead about a certain sub-genre of horror that has been popular of late: the single shaky camera film. The Blair Witch Project (a film undone by rumors of eeriness, if ever there was one) probably gave birth to the genre. It has recently been employed in two much better productions: Cloverfield, and Quarantine. In each movie, what you see on the screen is presented as a recording made on a single video camera, carried by one or more of the characters.
It is not hard to see why this device is irresistible to directors. It puts the camera and with it the viewer right into the action, producing a visceral sense of reality. At the same time, it narrows the focus of the viewer in ways that heighten a natural sense of alarm. You, the viewer, can only see what the camera is pointed at, but you constantly sense that something you desperately need to see may be going on just outside your view. In each of the three films just mentioned, the fact that the characters are filming what happens is merely incidental to the action. But what if the fact that a horror is being filmed is itself part of the horror? Something there may be that doesn't like a digital camera. Just a thought.
The shaky camera film does have its problems. It's hard to imagine that someone running like Hell from a giant monster, or zombies, or the Blair Witch, would bother to keep filming. Unless, perhaps, the obsessive filming was an expression of the very character flaw that opens the door to some unspeakable evil. That's just more idle speculation.
I have scrupulously avoided telling you anything about Paranormal Activity. I won't spoil anything now by telling you that you should see this movie. I will tell you to take a good look and listen before you leave your home for the theater. It might not seem quite the same when you return.