What do the greatest horror movies all have in common?
They all have unforgettable soundtracks that bring about an instant feeling of terror. In fact, if you watch the films without any sound, they become a lot less scary.
But what is it about the music that makes 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 evident survival advantage to the immediate acknowledgment of a deadly situation.
Thinking takes time, 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 deliberately.
Considering that it takes more time to process and contemplate visual information, the animal brain is wired to respond to quicker sound-processing mechanisms—a characteristic 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 alarmed. This yields a nearly instantaneous feeling of fear or anxiety.
But what is it about nonlinear sound that makes it frightening?
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 discern the properties of nonlinear sound as unpleasant and suggestive of hazardous circumstances.
The interesting thing is, we can artificially reproduce a variety of these nonlinear sounds to get the same instant fear response in humans.
So, what was once an effective biological adaptation in the wild has now been co-opted by the movie industry to manufacture scarier films.
Music and Fear
We all are familiar with the shower scene from the classic film Psycho, and it’s certainly one of the most frightening scenes in the history of film.
But if you view the scene on mute, it loses most of its impact. It’s only once you add back in the high-pitched screaming and bone-chilling staccato music that the fear response becomes thoroughly engaged.
To demonstrate our natural aversion to this nonlinear sound, UCLA evolutionary biologist Daniel Blumstein carried out a study examining the emotional responses to two types of music.
Participants in the study listened to a collection of emotionally neutral scores and scores that contained nonlinear elements.
As expected, the music with nonlinear characteristics aroused the most potent emotional responses and negative feelings. This response is simply an element 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 viewers.
Want to observe the fear response in action?
Listen to these 10 Essential Horror Movie Scores.