What do the greatest horror movies all have in common?
They all have unforgettable soundtracks that bring about an instantaneous sensation of terror. In fact, if you watch the films without any sound, they become a great deal less frightening.
But what is it regarding the music that renders it terrifying? More specifically, if sounds are just vibrations in the air, what is it about our biology that makes us respond with fear?
The Fear Response
In regard to evolutionary biology, there’s an evident survival advantage to the instantaneous identification of a harmful circumstance.
Thinking is time consuming, particularly when you’re staring a hungry lion in the face. When every second counts, you don’t have the time to stop and process the information deliberately.
Seeing as it takes additional time to process and contemplate visual information, the animal brain is wired to respond to swifter sound-processing mechanisms—a trait that offers survival advantage and has been selected for in the wild.
And that’s exactly what we see in nature: several vertebrates—humans included—emit and react to harsh, nonlinear sounds and vocalizations when frightened. This yields a nearly instant feeling of fear or anxiety.
But what is it about nonlinear sound that makes it scary?
When an animal screams, it generates a scratchy, irregular sound that stretches the capacity of the vocal cords past their normal range.
Our brains have evolved to distinguish the features of nonlinear sound as abnormal and suggestive of life-threatening circumstances.
The interesting thing is, we can artificially simulate a wide array of these nonlinear sounds to bring about the same instantaneous fear response in humans.
So, what was once an effective biological adaptation in nature has now been co-opted by the movie industry to manufacture scarier movies.
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 most of its impact. It’s only once you incorporate back in the high-pitched screeching and bone-chilling staccato music that the fear response becomes thoroughly engaged.
To demonstrate our instinctive aversion to this nonlinear sound, UCLA evolutionary biologist Daniel Blumstein conducted a study assessing the emotional reactions to two types of music.
Participants in the study listened to a collection of emotionally neutral scores and scores that included nonlinear elements.
As anticipated, the music with nonlinear elements aroused the most potent emotional reactions and negative feelings. This response is simply part of our anatomy and physiology.
Regardless of whether Hollywood understands this physiology or not, it appreciates intuitively that the use of nonlinear disharmonious sound is still the most effective 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.