Photo: Green Epstein Productions

This piece was originally published in October of 2014.

Horror is a genre that constantly reinvents itself, yet certain tropes have remained in place for decades. The demon-possessed doll in The Conjuring franchise is part of a pantheon of scary dolls that includes Chucky from Child’s Play (1988), Talky Tina from The Twilight Zone (1963), and Hugo the ventriloquist’s dummy in Dead of Night (1945). The freaky masks worn by killers in The Purge and You’re Next have their origins in classic Universal horror villains like The Phantom of the Opera (1925) and The Invisible Man (1933). Then there’s a long tradition of scary clowns — that’s Pennywise from It, the latest adaptation of which hits theaters this Friday, pictured above. So why is it that these images are just as frightening now as they were to our great-grandparents?

Clearly, there’s some deep psychology at work here. Vulture called up Harvard Medical School psychiatrist and fright-film fan Steven Schlozman — who teaches an undergraduate course on the psychology of horror — to find out why certain things stay scary.

Let’s start with something that’s always been a staple of horror movies: faces altered by deformities, mutations, or creepy masks. Why are they so unsettling?

There is an aspect of horror that Freud initially called the uncanny. That’s where something is familiar enough to be recognizable but weird enough to give you the shivers. The uncanny explains a lot of horror tropes, where you look at something and it’s not quite right — like a human face that’s decomposing. It’s recognizable, but just enough away from normal to scare you. In my lectures, I’ll show a slide of a beagle, and I have a series of Photoshopped slides where I keep changing the eyes of the beagle and it gets creepier and creepier, because you recognize that there’s something not right about it, and it takes you a second to place it.

What about circuses and clowns? Why are they disturbing?

That’s the uncanny at work, but there’s another part to it. Clowns, by definition, are supposed to make you laugh, but in the background is the fear that they won’t, and all of us have that in the back of our mind: the fear that you won’t actually be able to do the very thing that you’re designed to do. In fact, clowns in the Middle Ages, if they didn’t make the king laugh, they paid a pretty steep price. A lot of the jesters were mutilated to make them smile all the time. They would have the muscles cut that enabled the mouth to frown.

That is possibly the freakiest horror trope: unnatural smiles.

I just went back and watched Magic with Anthony Hopkins, the one with the puppet, which I hadn’t seen in a long time, and when that ventriloquist doll has this creepy stuck grimace, it’s horrifying. Again, you recognize a smile, your brain registers that smiles are largely good things — and yet you can’t smile all the time, because if you’re smiling all the time, something’s not right. Like when Tony Soprano smiles all the time, it’s really bad for whoever he’s talking to. So I think that’s similar to clowns, in that we take cues from the way people behave, but if there’s no change in the way they look or the way they act — think of Javier Bardem’s face in No Country for Old Men — that makes them very scary.

What about tropes that are completely outside most of our experience, like blood dripping from walls or screams coming from the basement?

Those tropes are kind of a-ha moments where you know beyond a doubt that this is not going to go well. Like in The Blair Witch Project, when they find human teeth hanging from the trees: Among the things this could be, none of them are good. That’s the opposite of the uncanny. The uncanny is when pattern recognition goes out the window. Whereas you have enough of a template to know that teeth should be in mouths and not hanging from trees. So you’re safe in assuming that something bad will likely happen. “The calls are coming from inside the house” is another trope like that. That’s the moment where it all comes together for you: These creepy calls now make sense in the worst possible way.

How about situational tropes, like being lost in the woods?

This trope brings up really interesting ethical questions. Like, when do you stop to help somebody, even if you know it puts your own life at risk? Horror movies love to play with those ideas. All those kids in the cabins in the woods are about that. There’s also a helplessness that goes with a lot of horror movies. Mouths sewn shut is the classic one there — you need to scream, but you can’t. It gets taken to a whole new gross level in movies like The Human Centipede.

Why are psychiatric hospitals and insane asylums such a horror staple?

Psychiatric hospitals scare people for two reasons. One is that we are frightened of that which we see in ourselves. People will often tell me, when they say they don’t like studying psychiatry, “I don’t like it because I just can’t understand it.” I’ll say, “Actually, it’s the thing that’s closest to you. That’s why I think you don’t like it.” You can’t imagine having a heart attack, but you could imagine being morbidly depressed or something. So it’s the idea of seeing people who are lot like you kept in horrific conditions. Second, there’s this whole largely fictional, but based on some reality, notion that once you’re in a psychiatric hospital, you have no rights. Having your freedom taken away still has that strong resonance.

There’s definitely a childhood thing going on in horror movies. What’s going on there?

A lot of horror is about lost innocence. If you look at Stephen King stories, a lot of them are about kids acting grown-up, or adults who have to solve something that they first confronted when they still had their innocence. Then there’s something about children as a kind of swarm, like in Children of the Corn. This is what got the critics upset in George Romero’s first movie, Night of the Living Dead. People were able to tolerate it up to the little girl stabbing her mother, and then they just lost it. People walked out, people were screaming, people called it subversive, thought it was dangerous.

How about the ever-popular zombie?

What people find scary about the living dead isn’t the living dead at all, it’s the way everybody responds to each other when the living dead are around. That’s where the money is in these movies. That’s what makes The Walking Dead so scary: The zombies are just big, empty vessels, and we can’t tolerate something that’s not going to care about us, especially that’s going to kill us. That drives us crazy. So we turn on each other.

Let’s finish with the scary Christians trope. Where does that fear come from? There have been a whole lot of exorcism movies lately.

There’s also been a run of gothic southern tent-preaching in movies and TV, like on True Detective and Justified. Idolatry’s always scary — intense, unwavering devotion the absence of even a slight question. It’s one thing to say, “I believe because I have faith” — I’m all for that, and I myself have faith. But it’s very different to say, “I will accept no other point of view.” Once you say that, and if the activity you’re engaging in is one that necessarily puts others in harm, you’re in trouble.