What do the best horror movies all have in common?
They all have unforgettable soundtracks that elicit an instantaneous sensation of fear. As a matter of fact, if you watch the films without any sound, they become a great deal less scary.
But what is it regarding the music that renders it terrifying? More specifically, if sounds are simply vibrations in the air, what is it about our biology that makes us react with fear?
The Fear Response
With respect to evolutionary biology, there’s an evident survival advantage to the instantaneous identification of a hazardous 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 deliberately.
Given that it takes a bit longer to process and ponder 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 exactly what we find in nature: numerous vertebrates—humans included—generate and respond to harsh, nonlinear sounds and vocalizations when alarmed. This yields a virtually instant sensation of fear or anxiety.
But what is it about nonlinear sound that makes it scary?
When an animal screams, it generates a scratchy, irregular sound that stretches the capacity of the vocal cords past their typical range.
Our brains have evolved to discern the features of nonlinear sound as unpleasant and indicative of life-threatening circumstances.
The interesting thing is, we can artificially emulate a wide array 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 manufacture scarier movies.
Music and Fear
We all are familiar with the shower scene from the classic film Psycho, and it’s definitely one of the most terrifying scenes in the history of cinema.
But if you view the scene on mute, it loses most of its affect. It’s only once you incorporate back in the high-pitched screeching and bone-chilling staccato music that the fear response becomes fully engaged.
To demonstrate our instinctive 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 contained nonlinear properties.
As expected, the music with nonlinear elements elicited the most potent emotional reactions and negative feelings. This response is simply a natural part of our anatomy and physiology.
Whether Hollywood comprehends 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 observe the fear response in action?
Listen to these 10 Essential Horror Movie Scores.