What do the greatest horror movies all have in common?
They all have memorable soundtracks that elicit an instantaneous sense of terror. In fact, if you view the films without any sound, they become a lot less scary.
But what is it regarding the music that makes it terrifying? More specifically, if sounds are simply vibrations in the air, what is it about our biology that causes us to respond with fear?
The Fear Response
In terms of evolutionary biology, there’s an obvious survival advantage to the immediate identification of a harmful situation.
Thinking takes time, 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 consciously.
Seeing that it takes longer to process and think about visual information, the animal brain is wired to respond to quicker sound-processing mechanisms—a trait that offers survival advantage and has been selected for in the wild.
And that’s exactly what we discover in nature: several vertebrates—humans included—generate and react to harsh, nonlinear sounds and vocalizations when frightened. This generates a virtually instantaneous feeling of fear or anxiety.
But what is it about nonlinear sound that makes it scary?
When an animal screams, it produces a scratchy, irregular sound that extends the capacity of the vocal cords past their normal range.
Our brains have evolved to detect the characteristics of nonlinear sound as abnormal and indicative of dangerous circumstances.
The fascinating thing is, we can artificially imitate a wide array of these nonlinear sounds to bring about the same immediate 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 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 once you incorporate back in the high-pitched screaming and bone-chilling staccato music that the fear response becomes thoroughly engaged.
To confirm our natural aversion to this nonlinear sound, UCLA evolutionary biologist Daniel Blumstein carried out a study investigating the emotional reactions to two types of music.
Participants in the study listened to a collection of emotionally neutral scores and scores that incorporated nonlinear properties.
As predicted, the music with nonlinear characteristics elicited the most potent emotional responses and negative feelings. This response is simply part of our anatomy and physiology.
Whether Hollywood understands this physiology or not, it appreciates instinctively that the use of nonlinear disharmonious sound is still the best way to get a rise out of the audience.
Want to witness the fear response in action?
Check out these 10 Essential Horror Movie Scores.