What do the greatest horror movies all have in common?
They all have unforgettable soundtracks that arouse an immediate sense of fear. Indeed, if you watch the films without any sound, they become a lot less scary.
But what is it regarding the music that makes it frightening? More specifically, if sounds are just oscillations in the air, what is it about our biology that causes us to respond with fear?
The Fear Response
With respect to evolutionary biology, there’s an evident survival advantage to the instantaneous identification of a hazardous circumstance.
Thinking takes time, especially 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.
Since it takes more time to process and think about visual information, the animal brain is wired to respond to faster sound-processing mechanisms—a trait that provides survival advantage and has been selected for in the wild.
And that’s exactly what we see in nature: numerous vertebrates—humans included—produce and react to harsh, nonlinear sounds and vocalizations when frightened. This produces a nearly instant feeling of fear or anxiety.
But what is it about nonlinear sound that makes it frightening?
When an animal screams, it generates a scratchy, irregular sound that stretches the capacity of the vocal cords past their typical range.
Our brains have evolved to distinguish the features of nonlinear sound as abnormal and suggestive of life-threatening circumstances.
The fascinating thing is, we can artificially emulate a variety of these nonlinear sounds to get the same instant 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 films.
Music and Fear
We all are familiar with the shower scene from the classic movie Psycho, and it’s probably one of the most terrifying scenes in the history of cinema.
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 examining the emotional responses to two types of music.
Participants in the study listened to a collection of emotionally neutral scores and scores that included nonlinear properties.
As expected, the music with nonlinear characteristics aroused the most potent emotional responses and negative feelings. This response is simply a natural 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 viewers.
Want to observe the fear response in action?
Listen to these 10 Essential Horror Movie Scores.