What do the top horror movies all have in common?
They all have memorable soundtracks that bring about an immediate sense of fear. In truth, if you watch the films without any sound, they become a great deal less frightening.
But what is it about the music that renders it terrifying? More specifically, if sounds are merely oscillations in the air, what is it about our biology that makes us respond with fear?
The Fear Response
With respect to evolutionary biology, there’s an obvious survival advantage to the instantaneous identification of a life-threatening circumstance.
Thinking is time consuming, 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 deliberately.
Given that it takes more time to process and contemplate visual information, the animal brain is wired to react 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: many vertebrates—humans included—produce and react to harsh, nonlinear sounds and vocalizations when frightened. This produces a virtually instantaneous sensation 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 extends the capacity of the vocal cords beyond their typical range.
Our brains have evolved to recognize the attributes of nonlinear sound as unpleasant and indicative of hazardous situations.
The fascinating thing is, we can artificially mimic a wide array of these nonlinear sounds to bring about the same immediate fear response in humans.
And so, what was once a successful biological adaptation in the wild has now been co-opted by the movie industry to manufacture scarier movies.
Music and Fear
We all are familiar with the shower scene from the classic movie Psycho, and it’s certainly one of the most terrifying scenes in the history of film.
But if you watch the scene without sound, 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 thoroughly engaged.
To reveal our instinctive aversion to this nonlinear sound, UCLA evolutionary biologist Daniel Blumstein conducted a study examining the emotional responses to two types of music.
Study participants listened to a selection of emotionally neutral music scores and scores that contained nonlinear properties.
As anticipated, the music with nonlinear characteristics elicited the most powerful emotional responses and negative feelings. This response is simply an integral part of our anatomy and physiology.
Whether Hollywood comprehends this physiology or not, it knows intuitively that the use of nonlinear discordant sound is still the best way to get a rise out of the audience.
Want to observe the fear response in action?
Listen to these 10 Essential Horror Movie Scores.