What do the top rated horror movies all have in common?
They all have memorable soundtracks that elicit an instantaneous sense of fear. In truth, if you watch the films without any sound, they become a great deal 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 makes us respond with fear?
The Fear Response
In terms of evolutionary biology, there’s an evident survival advantage to the immediate detection of a threatening situation.
Thinking takes time, especially 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 deliberately.
Given that it takes additional time to process and contemplate 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 discover in nature: numerous vertebrates—humans included—produce and respond to harsh, nonlinear sounds and vocalizations when frightened. This yields a nearly instantaneous 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 extends the capacity of the vocal cords beyond their normal range.
Our brains have evolved to identify the qualities of nonlinear sound as abnormal and suggestive of life-threatening circumstances.
The interesting thing is, we can artificially emulate a variety of these nonlinear sounds to get the same instantaneous fear response in humans.
And 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 movie Psycho, and it’s definitely one of the most terrifying scenes in the history of film.
But if you view the scene without sound, it loses the majority 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 reveal our natural aversion to this nonlinear sound, UCLA evolutionary biologist Daniel Blumstein conducted a study investigating the emotional responses to two types of music.
Participants in the study listened to a collection of emotionally neutral music scores and scores that included nonlinear elements.
As anticipated, the music with nonlinear elements aroused the strongest emotional reactions and negative feelings. This response is simply a natural part of our anatomy and physiology.
Whether Hollywood understands this physiology or not, it appreciates instinctively that the use of nonlinear discordant 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.