How great jump scares are made in horror movies

• Horror films are filled with jump scares, moments that shock and startle viewers as monsters, serial killers, ghosts and even cats pop out of the darkness. But while jump scares are a very common element to include in a scary movie, they don't always work as intended, and often, you might just end up laughing instead of screaming.

• To find out what goes into creating an effective jump scare we spoke with Rebekah McKendry. a film professor at USC who specializes in horror.
• What makes certain scenes in "The Conjuring," "Insidious," and "The Exorcist 3" so terrifying while others like in "Friday the 13th Part VIII: Jason Takes Manhattan" fall flat?

Following is a full transcript of the video.

Narrator: This is the reveal of the witch in 2013's "The Conjuring."

Compare that to this reveal of Jason in "Jason Takes Manhattan."

The first one is much scarier, but don't just take my word for it.

Jason has certainly had his scary moments, but one of the main reasons "Jason Takes Manhattan" is ranked so low is because it doesn't follow the rules for making a movie scary.

And while there's no exact formula, there are certain time-tested secrets you can include to create a truly terrifying jump scare, according to this woman...

Rebekah McKendry: My students kind of jokingly know me as Dr. Horror.

Narrator: Who has a PhD in horror.

McKendry: So, jump scares are based on kind of a theory of what fear is. Fear is kind of the buildup.

It's the time in between when you think something might happen to when it actually happened.

Narrator: You can usually tell when a jump scare is about to happen.

The lighting dims, the editing slows down, things might start moving by themselves, and the music gets, well, creepy.

But those are the more obvious clues. So, what is the first thing that helps build to a jump scare?

McKendry: I call it breadcrumbs. You get some type of indication that something scary may be likely to happen. The closet door opens slightly. We see a window open. There's a weird noise coming from the corner.

Narrator: There are a few famous audio examples of this from classic horror. In the "Friday the 13th" series, you know something bad is about to happen when you hear Jason's...

Jason: Ki ki ki ma ma ma ki ki...

Narrator: Or when you hear the famous [suspenseful music] in "Jaws."

But the breadcrumbs we're talking about are often more subtle, like in this scene from the 2002 film "Below." The character's reflection starts to lag in the mirror, so you begin to get that feeling that something is very wrong and that something even more scary is about to happen.

Now let's take a look back at that wardrobe scene in "The Conjuring." There are several breadcrumbs that lead us to the final witch scare. We first have the sound of a closet door banging.

[closet door bangs]

Then the visual of the girl walking in her sleep.

[closet door bangs]

Andrea: Cindy?

Narrator: Notice the camera hardly moves and the wardrobe never leaves the wide shot. And then we get the sound of even more banging. Only this time, the girl is back in her bed, so we know it's not her anymore.

[closet door bangs]

[closet banging continues]

Cue the creepy music.

[suspenseful music]

Each breadcrumb raises our level of anxiety a little bit more, like a balloon gradually getting more inflated until it finally pops.

There are no specific breadcrumbs in the "Jason Takes Manhattan" scene. And, in fact, we don't even hear the classic "ki ki ki ma ma ma" until after we know Jason is already right behind them.

Jason: Ki ki ki ki ki ki...

Narrator: Once we see and hear these clues, that doesn't mean the scare is gonna come right away. In fact, for most great jump scares, the opposite is true. You have to make the viewer wait by dragging out the scene until the tension is too much to bear.

Alfred Hitchcock famously said: "There is no terror in the bang. Only in the anticipation of it."

McKendry: Once the gun is fired, the fear is done. It's over with. There's nothing left to be scared of. Once the gun is fired, the scene is over.

Narrator: An effective jump scare can take time. Even the majority of the movie, in some cases. But if done right, the payoff will be well worth it.

One great example of buildup is this nurse-station scene in "The Exorcist III." The camera doesn't move at all for about three minutes while nurses and security guards shuffle around. We know something is about to happen. We just don't know when, and it takes its time to get there.

This scene in "Insidious" is another great example of building tension. Only instead of a single shot, we alternate back and forth between two characters for an extended period of time. The conversation goes on for about two minutes before the demon finally appears. And even though we know something is about to happen, when it does, we're caught off guard.

The wardrobe scene in "The Conjuring" takes place over about two minutes after the first breadcrumb. Director James Wan lets the scene play out very slowly, with a creeping sense of dread.

The scene in "Jason Takes Manhattan" is also long, about two minutes. But Jason is revealed so early on in the scene with no buildup about one minute after it starts. So the only thing we're waiting for is for the couple to see him 30 seconds later. For us as the audience, there's no tension, no anxiety.

It's during this period of buildup when the best horror movies will use a distraction to further amp up the tension.

Lars: Boo!

Derek: Jesus Christ.

Narrator: Think of this part like a magic trick. You're encouraged to look in one direction while the real threat is happening elsewhere.

In this famous scene in "Jaws," we're distracted by the discovery of a tooth, and we're expecting to see a shark. Instead, we get a corpse.

In "The Sixth Sense" when Cole and the audience is focusing on the closet, an arm shoots out from under the bed.

One common and often overused form of misdirection is the mirror trope. Where the protagonist opens a medicine cabinet, for example. Alone at first, when it shuts, something is standing behind them. Surprise!

The technique was first used in Roman Polanski's 1965 film "Repulsion" and can be found in numerous other films to this day.

In "The Conjuring," both the camera and girl are focused on the closet. We think something is inside of it, ready to jump out. But in reality, the threat is actually on top of the wardrobe.

"Jason Takes Manhattan" doesn't even try to fool us at all. The main characters have a false sense of security.

Sean: It's over.

Narrator: But we as the viewer already know where the threat is the entire time. This brings us to another visual trick with jump scares. Making the audience feel more anxious by limiting what they can see.

McKendry: Anything that you can do to limit the character, and through that, the audience's frame of vision, will always increase the anxiety and the scare of it.

Narrator: There are two ways of accomplishing this, camera and lighting. Let's take a look at lighting first. Some common tricks are to use a camera flash, like this scene in "Mama," or a device like night-vision goggles in "The Descent" to narrow the character's and our scope of vision. Notice how much of the scene is obscured in these shots. We have very little space to feel safe.

McKendry: All of these things have what we call in lighting a hard falloff, meaning there is a very sharp line between what you can see and what you can't see.

Narrator: That being said, you can still have jump scares during the day. But these require a bigger buildup, as we mentioned earlier, for them to be effective.

Just look at this terrifying moment in "Mulholland Drive." We don't see the creature outside the diner until after an entire three-minute-long buildup of conversation inside the diner.

"The Conjuring" limited how much we can see by having only one small lamp by the bed in an otherwise dark room far away from the wardrobe. Jason, on the other hand, is standing in a brightly lit Times Square, where the only time he's obscured is when two people pass in front of him. The other way to limit view is by using the camera.

McKendry: It is very common in horror films to limit the character's kind of vision, their frame of reference, where they're looking through keyholes. They might be trapped in a closet and they're looking out slats of a closet. And really kind of limit how much they can see. And with that, you are limiting how much the audience can see as well.

Narrator: Let's take a look at this scene in "The Shining." The camera is following Danny, so we as the audience can't see around the corners of the hall until he does, when it's too late.

When Arbogast is walking up the steps in "Psycho," the camera is focused on him, so we are also blind to what's around him and what's about to happen. It creates an added sense of anxiety in the viewer.

McKendry: The tighter you are and the more confined you are and the less information you have about the situation, that's when it's scary.

Narrator: And camera movements can also force you into areas you wouldn't normally choose to go.

McKendry: If the closet is slightly open, the camera may start pushing into the darkness slightly. The filmmaker is forcing you as the audience to get closer to it, whether you want to or not. Or, sometimes, the camera will hold perfectly still. And that in itself can be equally anxious, 'cause we're used to movement and cuts and things like that.

Narrator: And when a scare finally appears, it's typically accompanied by a loud sound.

This sound is known as a sting. A good example of a sting can actually be heard in the opening credits of "Insidious," a film that is full of effective jump scares. The crash accentuates the moment we are supposed to be scared. [screeching music]

There's certainly a sting when the witch appears in "The Conjuring," accompanied by a camera push-in.

[witch growling loudly]

And there's actually two in "Jason Takes Manhattan."

[air whooshing loudly]

Jason: Ki ki ki ki...

[screeching music]

Narrator: But these are both ineffective, since we've already seen Jason. There's no peak moment of anxiety that is elevated by the sound.

A sting can only work so well without a good buildup. There are numerous examples of this in horror films, where the jump scare and the loud sting come completely out of nowhere. Sure, you may be startled, but this fear won't last.

"Deep Blue Sea" has a memorable jump scare with a sting, but there's no breadcrumb and no buildup. And so while the scene is certainly violent and unexpected, there's also no real fear after the shark eats him. And the absurdity of it all might just make you laugh instead.

And after all of the work to build up the scare, the threat needs to hold up as well.

In a lot of movies, the threat isn't real, but it can still make you jump.

McKendry: Oh, my gosh, the closet door's opening, we're getting closer, closer, closer, the music's swelling, the camera's pushing in, and then it's a cat.

Cats have had more jump scares in horror history than any monster ever had.

Narrator: Like in "The Amityville Horror" when one just appears outside the window.

One of the most famous fake scares -- it's actually not a cat -- was this bus in the 1942 film "Cat People." [bus whooshing loudly] In fact, this scene went on to inspire other filmmakers to mimic the fake scare and has become known as "the Lewton Bus technique," named after the film's producer, Val Lewton.

Another famous example of this is the Pop-Tart scene in "Silent Hill." While it might make you jump, there's nothing terrifying about a Pop-Tart unless you have a gluten allergy.

Horror movies are littered with these types of cheap scares, which ultimately hurt the movie as a whole because they haven't been earned and don't move the story forward. The best way to use a jump scare is to not overuse it.

Too many jump scares takes away from the impact of them. And sometimes you don't even need them at all.

In fact, best-picture winner "The Silence of the Lambs" doesn't even have one jump scare in the entire movie. And the classic "Texas Chain Saw Massacre" only has two.

McKendry: If you're just up here the whole time, you go flat. There's nowhere else to go. And so it's all about kind of taking the audience on a roller-coaster ride of hills and loops, but not trying to keep them suspended in the air the entire time.

Narrator: And when a jump scare does work well, you'll know, because you'll see it pop up again and again, replicated in newer films as a tribute to its original success and the work that went in to crafting it.