How Composers Make Horror Movie Music Sound Terrifying
The iconic shower scene in Psychology was originally supposed to be played without music. Instead, composer Bernard Herrmann created “The Murder”: as the murder occurs, the violins scream and scream along with the victim.
The film’s director, Alfred Hitchcock, was later quoted as saying that “33% of the effect of Psychology was due to the music. In most horror films, the emotional undercurrent that carries viewers is the music, which heightens their anticipation and heightens the scares. It’s not just screaming violins: rippling synthesizers enliven John Carpenter’s sound. Halloween; the “evil” clarinets support Hereditary; a 1930s recording improves To go out.
Studies have shown that certain scary music activates the brain’s alarm response system. So what makes some music scary? Psychoacoustics researchers have found that some common auditory characteristics in horror music are inherently frightening. The most obvious way music can scare us is by literally imitating screaming, like Psychology do. Here the instruments imitate a quality of human cries called roughness. When we scream, we pass a high volume of air through our vocal cords, causing them to vibrate chaotically. This creates a sound wave with rapidly fluctuating amplitude, which our ears and brain perceive as rough or harsh.
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To imitate this musically, violinists must push the limits of their instruments. “They’re literally pushing on that string, just pushing the capacity of the instrument. You feel like the whole instrument is almost resisting the sound,” says Caitlyn Trevor, a music cognition researcher and founder of sound design consulting firm SonicUXR. In a 2020 study, when Trevor was a researcher at the University of Zurich, she and her colleagues studied horror movie soundtracks and found many of these screaming musical cues.
Rude vocalizations seem to have privileged access to our brain. In a study published in May, scientists found that the sound of a distant cry could elicit a response from the brain even in the deepest phase of sleep. When you hear a scream, it quickly activates the amygdala, a brain structure involved in processing danger, and can trigger a cascade of alarm responses in the nervous system. The brief burst of sound can also trigger our startle reflex, which bypasses higher-order brain regions and goes straight to our body to help us respond quickly.
However, most horror music is not directly intended to provoke terror. These moments of auditory release are generally preceded by long, bubbling pieces that create suspense. “There are actually two very different types of music: ‘scary’ or ‘scary’,” says Trevor. In 2023, she co-authored a study examining the musical differences between these two types of horror film songs. Participants rated the emotional effects of different excerpts. The results showed a distinction between anxiety-provoking and terrifying music; the two types “sometimes have completely opposite sonic characteristics,” says Trevor. Where the terrifying music was loud, brash and dense (a chorus of screaming string instruments from Midday was ranked as the most terrifying of all the examples in the study), anxiety-inducing music tended to be more varied. This is where composers have the most room to play, using subtle biologically rooted auditory cues to keep listeners engaged.
For example, some horror films use (or are rumored to use) very low frequency sounds at the edge of human perception to convey an intangible feeling of doom. “Certain sounds mimic the danger that exists in the world,” says Susan Rogers, a music producer and music cognition researcher at Berklee College of Music. “A low rumble is something we evolved to pay attention to,” she says, perhaps signaling a stampede, a storm, an earthquake, or something dangerous in the environment.
Fast tempos, especially those that sound like a heartbeat, can also put us on edge, says Rogers. In the theme of John Carpenter Halloween, a dull sound reminiscent of a heartbeat moves the music forward. “A predictable rhythm gives you a sense of momentum and that [the filmmakers are] leading towards something,” says Trevor. The listener doesn’t know where the music or the story is going, but they feel relentless and inevitable.
More often than not, however, horror film music creates suspense by making itself unpredictable. Thriller music, Trevor discovered in his 2023 study, often keeps us in suspense by sprinkling bits of sound in unexpected places. Sometimes these scores use an unpredictable or unbalanced rhythm, dropping notes here and there, to prevent the listener from settling into the rhythm, she adds.
“The soundtrack and sound design are integral to predicting what will happen, so sound designers for horror films can use the technique of violating our predictions to make us feel fear,” says Rogers. The brain is a prediction machine and it allows us to tune out expected or constant noise. “Whether it’s a car engine or a thunderstorm, we know how it’s going to happen, so we turn our attention to other things,” she continues. If you hear footsteps coming up the stairs, you might predict that they will continue until they reach the top; but if they stop halfway, you become alert. These sorts of “prediction errors” activate the amygdala and a memory-forming region called the hippocampus.
But some of the scariest features of horror movie music are cultivated and may not be scary in and of themselves. For example, composers often create tension in music by using dissonance, when the pitches of two or more notes seem to clash. The idea that some harmonies are inherently dissonant has some truth: if two notes are too close together in pitch, sound waves can interfere, causing a “beat” pattern that can be unpleasant or irritating to the ear. “But only at the most basic level is this universal. Beyond that, the musical concept of consonance and dissonance is entirely learned,” says Rogers.
Other harmonies that were once considered inherently dissonant—for example, the so-called devil’s chord, or tritone, which is often used in horror films—are perceived differently in different cultures. A 2016 study found that the Tsimane’ people of rural Bolivia, a group whose music does not use harmony, rated the tritone and other “dissonant” intervals as pleasant as “non-dissonant” intervals.
Some of the most creative horror movie soundtracks play on our cultural expectations to create a feeling of unease or fear, Trevor adds. Many horror films use old records, which have a warbling sound quality and often feature an old-fashioned way of singing that sounds strange to our modern ears. This can create a strange valley effect: something that should be familiar is instead subtly strange. “You know what it is, but there’s something wrong,” Trevor said. “It’s not RIGHT. And it’s really disturbing on a deep level.
