What do the top horror movies all have in common?
They all have memorable soundtracks that arouse an immediate sense of fear. As a matter of fact, if you watch the films without any sound, they become a lot less scary.
But what is it about the music that renders it frightening? More specifically, if sounds are simply oscillations in the air, what is it about our biology that makes us react with fear?
The Fear Response
In terms of evolutionary biology, there’s an evident survival advantage to the automatic identification of a threatening circumstance.
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.
Considering it takes more time to process and contemplate visual information, the animal brain is wired to react to faster sound-processing mechanisms—a characteristic that offers survival advantage and has been selected for in the wild.
And that’s precisely what we see in nature: numerous vertebrates—humans included—generate and react to harsh, nonlinear sounds and vocalizations when alarmed. This generates 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 extends the capacity of the vocal cords beyond their normal range.
Our brains have evolved to distinguish the attributes of nonlinear sound as abnormal and indicative of life-threatening situations.
The intriguing thing is, we can artificially reproduce 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 know the shower scene from the classic film Psycho, and it’s certainly one of the most terrifying scenes in the history of cinema.
But if you watch the scene on mute, it loses the majority 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 reveal our natural aversion to this nonlinear sound, UCLA evolutionary biologist Daniel Blumstein conducted a study evaluating the emotional reactions to two types of music.
Participants in the study listened to a selection of emotionally neutral music scores and scores that included nonlinear properties.
As anticipated, the music with nonlinear characteristics elicited the most potent emotional responses and negative feelings. This response is simply a natural part of our anatomy and physiology.
Whether Hollywood comprehends this physiology or not, it appreciates intuitively that the use of nonlinear disharmonious sound is still the most effective way to get a rise out of the audience.
Want to see the fear response in action?
Check out these 10 Essential Horror Movie Scores.