What do the greatest horror movies all have in common?
They all have memorable soundtracks that elicit an instantaneous sensation of fear. In truth, 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 vibrations in the air, what is it about our biology that causes us to react with fear?
The Fear Response
With respect to evolutionary biology, there’s an obvious survival advantage to the automatic identification of a detrimental situation.
Thinking takes time, particularly 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 consciously.
Seeing that it takes additional 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 precisely what we find in nature: numerous vertebrates—humans included—produce and react to harsh, nonlinear sounds and vocalizations when alarmed. This creates 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 beyond their normal range.
Our brains have evolved to recognize the characteristics of nonlinear sound as unpleasant and suggestive of life-threatening situations.
The fascinating thing is, we can artificially simulate a wide array of these nonlinear sounds to bring about the same instant fear response in humans.
So, what was once a successful biological adaptation in nature has now been co-opted by the movie industry to produce scarier movies.
Music and Fear
We all are familiar with the shower scene from the classic film Psycho, and it’s probably 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 affect. It’s only when you incorporate back in the high-pitched screeching and bone-chilling staccato music that the fear response becomes fully engaged.
To confirm our natural aversion to this nonlinear sound, UCLA evolutionary biologist Daniel Blumstein conducted a study examining the emotional reactions to two types of music.
Study participants listened to a selection of emotionally neutral music scores and scores that incorporated nonlinear properties.
As anticipated, the music with nonlinear elements elicited the most potent emotional responses and negative feelings. This response is simply a part of our anatomy and physiology.
Whether Hollywood understands this physiology or not, it knows intuitively that the use of nonlinear disharmonious sound is still the most effective 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.