What do the best horror movies all have in common?
They all have memorable soundtracks that bring about an immediate feeling of fear. In truth, if you view 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 simply vibrations in the air, what is it about our biology that causes us to react with fear?
The Fear Response
In terms of evolutionary biology, there’s an obvious survival advantage to the immediate detection of a harmful scenario.
Thinking is time consuming, 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 consciously.
Seeing as it takes more time to process and contemplate visual information, the animal brain is wired to react to quicker sound-processing mechanisms—a characteristic that provides survival advantage and has been selected for in the wild.
And that’s exactly what we discover in nature: a large number of vertebrates—humans included—produce and respond to harsh, nonlinear sounds and vocalizations when alarmed. This produces a nearly instant sensation of fear or anxiety.
But what is it about nonlinear sound that makes it scary?
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 features of nonlinear sound as abnormal and indicative of hazardous circumstances.
The intriguing thing is, we can artificially mimic a wide array of these nonlinear sounds to bring about 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 produce scarier films.
Music and Fear
We all know the shower scene from the classic movie Psycho, and it’s probably one of the most frightening scenes in the history of cinema.
But if you watch the scene without sound, it loses most of its impact. It’s only when you add back in the high-pitched screeching and bone-chilling staccato music that the fear response becomes thoroughly engaged.
To demonstrate our natural aversion to this nonlinear sound, UCLA evolutionary biologist Daniel Blumstein carried out 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 elements.
As predicted, the music with nonlinear characteristics aroused the strongest emotional reactions and negative feelings. This response is simply an element of our anatomy and physiology.
Regardless of whether Hollywood comprehends this physiology or not, it appreciates intuitively that the use of nonlinear disharmonious sound is still the best way to get a rise out of the viewers.
Want to see the fear response in action?
Listen to these 10 Essential Horror Movie Scores.