Jack-o-lantern in window

What do the best horror movies all have in common?

They all have memorable soundtracks that bring about an instantaneous sensation of terror. As a matter of fact, if you view the films without any sound, they become a great deal less frightening.

But what is it regarding the music that makes it frightening? More specifically, if sounds are simply oscillations in the air, what is it about our biology that makes us react with fear?

The Fear Response

In terms of evolutionary biology, there’s an obvious survival advantage to the instantaneous identification of a risky scenario.

Thinking is time consuming, especially when you’re staring a ravenous lion in the face. When every second counts, you don’t have the time to stop and process the information deliberately.

Considering it takes additional time to process and contemplate visual information, the animal brain is wired to react to faster sound-processing mechanisms—a trait that provides survival advantage and has been selected for in the wild.

And that’s precisely what we find in nature: a large number of vertebrates—humans included—generate and respond to harsh, nonlinear sounds and vocalizations when frightened. This creates a virtually instantaneous sensation of fear or anxiety.

But what is it about nonlinear sound that makes it alarming?

When an animal screams, it creates a scratchy, irregular sound that stretches the capacity of the vocal cords beyond their typical range.

Our brains have evolved to detect the attributes of nonlinear sound as unpleasant and indicative of hazardous situations.

The intriguing thing is, we can artificially emulate a wide array of these nonlinear sounds to bring about the same instant fear response in humans.

And so, what was once an effective biological adaptation in nature has now been co-opted by the movie industry to produce scarier films.

Music and Fear

We all are familiar with the shower scene from the classic film Psycho, and it’s definitely one of the most terrifying scenes in the history of film.

But if you watch the scene on mute, it loses the majority of its impact. It’s only when you incorporate back in the high-pitched screaming and bone-chilling staccato music that the fear response becomes thoroughly engaged.

To reveal our natural aversion to this nonlinear sound, UCLA evolutionary biologist Daniel Blumstein conducted a study assessing the emotional responses to two types of music.

Study participants listened to a selection of emotionally neutral scores and scores that included nonlinear properties.

As anticipated, the music with nonlinear characteristics elicited the strongest emotional responses and negative feelings. This response is simply a part of our anatomy and physiology.

Whether Hollywood comprehends this physiology or not, it appreciates instinctively that the use of nonlinear discordant sound is still the best way to get a rise out of the audience.


Want to observe the fear response in action?

Check out these 10 Essential Horror Movie Scores.