Growing up, Halloween was my least favorite holiday. As a kid (and to be honest, still as an adult) I was easily scared by almost anything. Having an entire day dedicated to the things that go bump in the night was like the embodiment of all my youthful nightmares— and one part of Halloween that always sent chills down my spine was its music. Years later, hearing the menacing laugh at the end of Michael Jackson's "Thriller," or the piercing strings in Psycho is enough to raise the hairs on the back of my neck. But what exactly is it about Halloween music that makes it so scary?

Last December, Vox published a video on Mariah Carey's "All I Want For Christmas Is You," analyzing just what makes the song sound so Christmassy. The video points to a specific chord used in "All I Want For Christmas Is You," the half-diminished (also known as minor 7 flat 5) built on the song's second scale degree. Vox explains that the same chord is used in various classic Christmas songs such as "Christmas (Baby Please Come Home)" and argues that it is the "secret sauce" that can make a Christmas song sound like Christmas.

While I found the video a tad click bait-y, and am not sure that you can boil down an entire genre to one chord, I was intrigued by its premise; uncovering what about the music itself can evoke a certain holiday. Sleigh bells and lyrical references to presents under the tree aside, what musical qualities evoke the spirit of Christmas? Inspired by this notion, I attempted to tackle the same question of Halloween: What musical qualities make a song a "Halloween song"?

What is a Halloween song?

Before I could delve into what makes a Halloween song sound Halloween-y, I first had to ask, What even is a "Halloween song"? I defined Halloween music as songs that are popular on or leading up to Halloween; the type of songs that would make it on Spotify's "Ultimate Halloween" playlist, or the tunes you would spin at a Halloween party. These songs don't have to be explicitly written about Halloween, they just have to be popular during that spooky time of year.

I used two main sources of data to identify popular Halloween music. My first data source was Billboard's lists of top Halloween songs from the past five years. These lists use a formula based on digital sales, radio airplay, and streaming, to determine which Halloween songs are most popular around the holiday each year.

To no surprise, Michael Jackson's "Thriller" snagged the number one spot for all five Billboard lists. Other popular songs included the novelty Halloween classic "Monster Mash" by Bobby "Boris" Pickett and the Crypt-Kickers, soundtrack titles like Ray Parker Jr.'s "Ghostbusters" and The Nightmare Before Christmas' "This Is Halloween," rock anthems including AC/DC's "Highway to Hell" and Blue Oyster Cult's "Don't Fear the Reaper," as well as spooky-themed pop songs like "Demons" by Imagine Dragons and the Eminem/Rihanna collaboration, "Monster."

The New York Times also published an article summarizing trends in Spotify streaming activity around Halloween. The piece states that around two weeks before Halloween is when streaming activity in Halloween music begins to spike. Who listens to Halloween music? According to the data, Utah is the most popular state for Halloween music, most communities that stream Halloween music are predominately white, and the biggest demographic that listens to Halloween music are women in their 30s and 40s.

While the data provided a starting point, it didn't give me any clear consensus on what makes a song a Halloween song. The most popular Halloween songs as reported by Billboard and Spotify looked like a smorgasborg of musical genres and eras. Where did all of this music come from, and what classifies it as Halloween-appropriate? In search of answers, I dug into the history of Halloween and its musical trends.

Where does Halloween music come from?

Like the history of Halloween music, the history of the holiday itself is a bit unclear. Halloween originated from the Celtic festival Samhain, celebrated in ancient Britain and Ireland. The ancient Celts believed that Nov. 1 was the beginning of the new year, and that the night before, the souls of those who had died would revisit their homes. People would set bonfires to frighten away evil spirits and sometimes wore masks or other disguises to avoid being recognized by the spirits. In the eighth century, the Catholic Church moved All Saints Day (originally May 13) to Nov. 1, possibly in attempt to replace the Pagan holiday with a Catholic one.

In addition to exercising control over holidays, the Christian Church had strict rules pertaining to music. Although created centuries ago, these rules affect how Western audiences hear music today. The Church only allowed composers to use "pure" or "holy" intervals in music, like octaves and perfect fifths. Basically, anything that sounded unsettling wasn't allowed. One particularly unsettling interval is called the tritone, whose jarring sound earned it the nickname "the devil's interval." Rumor has it, the Church banned use of the tritone during the Renaissance.

Moving into the 20th century, one genre notorious for its connotations with evil spirits is the blues. Various factors contributed to the blues' popular association with the devil, including the genre's secular and often sexual lyrics, as well as the its melancholy themes reflecting the lived experiences of racial oppression. With songs like "Cross Road Blues" and "Me and the Devil Blues," Robert Johnson was rumored to have sold his soul to the devil in exchange for his musical talent. Johnson was part of the legacy of Delta blues musicians, artists from the South, whose music laid the groundwork for rock and roll.

One of the most defining musical characteristics of the blues is the blues scale, a musical scale which prominently features a flatted fifth, known as the blue note. When played on top of the scale's root, the blue note creates a tritone, the familiar crunchy interval that the Church associated with the devil.

The dissonance of the blue note, plus the "unholy" themes of blues music earned it the nickname, "the devil's music," and various popular Halloween songs like Screamin' Jay Hawkins' 1956 "I Put a Spell on You" come out of this blues legacy.

While spooky themes had been brewing in popular music for centuries, it wasn't until the 1950s and '60s that the U.S. saw a fad for Halloween-specific songs. "Starting somewhere in the mid to late '50s, and running through a good chunk of the '60s, every single band out there seemed like they had to have at least one Halloween-ish novelty song in their catalog," said The Current's resident Halloween aficionado, Brian Oake. 

The majority of these songs were from doo-wop groups, like the Verdicts, who released the 1961 song "Mummy's Ball." Other Halloween novelty songs from this era include the Hollywood Flames' "Frankenstein's Den" (1958) and of course, Bobby "Boris" Pickett and the Crypt-Kickers' "Monster Mash" (1962). These songs all feature Halloween-related subject matter, but in terms of their musical characteristics, are indistinguishable from other non-Halloween-related doo-wop songs.

According to Oake, these bands released Halloween songs in hopes of landing sought-after radio play in an era where radio was one of the only ways for artists to reach large audiences. Maybe the singles' straightforward doo-wop sound attempted to appease fans of the genre, while banking on the spooky lyrics to garner radio attention around Halloween.

After the doo-wop of the '50s and '60s, Halloween music broke into more ambiguous sub-categories. Sinister themes are common among the classic and hard rock anthems of the 1960s to 1980s, some of which have since been adopted as Halloween songs — like AC/DC's "Highway to Hell" and the Rolling Stones' "Sympathy for the Devil." These genres were born out of the legacy of the blues, and as such, feature blues notes and blues-inspired chord progressions.

Another category of music associated with Halloween is horror film soundtracks. The 1970s and 1980s gave rise to an explosion of horror films, including classic titles like The Shining, The Exorcist, and Halloween. These films created their own musical canon consisting of string and analog synthesizer-driven music. Horror and sci-fi movies of this era popularized the use of two unusual instruments, the theremin and ondes martenot, which were pivotal in creating otherworldly tones. Because of these trends, modern audiences may associate the electronic warble of a theremin or the buzz of an analog synth with the sounds of Halloween.

What musical techniques can make a song sound spooky?

Already, I was beginning to see some common musical characteristics of Halloween songs from exploring the genre's history. But I still wasn't satisfied— I hadn't yet found the "secret sauce" that could make a song sound like Halloween. In search of answers, I identified three potential musical qualities that could make a song sound Halloween-y.

Dissonance

An interval, which is the relationship between two notes, can be described as either consonant or dissonant. A consonant interval has a simple ratio of the frequency between its two notes, which creates a pleasing or “resolved” sound. For example, the ratio between the frequencies of a C and a G (an interval known as a perfect fifth) is 3:2; a simple, and therefore satisfying ratio. If the ratio is complex, the interval will be dissonant, giving it a “crunchy” or unsettling sound. 

As we know, the tritone is an especially unsettling interval, and for good reason— it has the most complex frequency ratio of any interval: 45:32 or 64: 45 depending on how it is tuned.

Although it is the most popular contemporary Halloween song, Michael Jackson's "Thriller" doesn't include many examples of dissonance. However, the end of the intro features a particularly crunchy chord, a fully diminished 7th, which includes a tritone between the notes C# and G (occurs at 0:34 in the clip).

This tritone creates tension, keeping the listener on the edge of their seat to hear what chord will come next. However, the following chord releases that tension, and the rest of the song is fairly consonant.

Instrumentation and Timbre

Over the years, certain musical instruments have gained a spooky reputation. A large reason for associations of certain instruments with scary themes comes from film soundtracks. Bach's "Toccata and Fugue in D Minor" was used in various silent films in the 1920's, and in 1931 was featured in the opening credits to the 1932 film Dr. Jekyll and Mr. Hyde, cementing the song's association with scaring audiences.

Many 20th century horror films feature large string arrangements, including the iconic 1960's horror flick, Psycho. Classical Minnesota Public Radio host Steve Staruch remembers when Minnesota Orchestra conductor Sarah Hicks was rehearsing the music from the famous shower scene for her orchestra. Several European members of the orchestra had never seen the film, and were unfamiliar with its score.

"They were asking her about how to play this, and they were trying to make it as beautiful as possible, and she said, 'No, you don't understand, it's not beautiful.'" recounted Staruch. "It's like five minutes of pure aggression. The pitch isn't as important as the quality of the sound, the ugliness of the sound, and the out-of-mind quality; it's just not normal."

https://www.youtube.com/watch?v=8VP5jEAP3K4

The strings from Psycho are an example of the importance of timbre in creating a spooky atmosphere. Timbre describes the quality of a sound. The notes that the violins are playing in the Psycho shower scene aren't all that important; what matters is that they are played with a shrill, grating timbre. The timbre of those stabbed violin notes is what makes Staruch describe the piece as "five minutes of pure aggression."

Ostinato

A key quality of many Halloween songs is a feeling of suspense. The sensation that there is someone behind your shoulder, that the monster you are hiding from can hear your stifled breathing.

Brian Oake identified this suspense as a key element of Halloween culture. "I don’t like the gore and the blood; that’s not what appeals to me," he said. "What I like is that slow, growing sense of unease and menace. For me, songs that do that for you, that create that atmosphere and push you out of your central comfort zone; for me that’s what Halloween is all about."

One technique used to create suspense in music is the repetition of a musical phrase. This repetition is called ostinato. One famous example of ostinato is the two repeated notes in the theme of Jaws.

Another example of ostinato is the repeated piano melody of John Carpenter's theme to Halloween.

https://www.youtube.com/watch?v=VLFx30Ijiq0

So, what does Halloween really sound like?

What did I learn out of this extensive dive into Halloween music? Did I find the secret musical element that can make a song sound like Halloween? Not quite. As I realized, Halloween music is a somewhat ambiguous category, for several reasons.

Although there are songs associated with Halloween, the holiday's musical canon (or that of any other holiday) doesn't come close to the plethora of songs that surrounds Christmas. Maybe no other holiday is central enough to Western culture to garner that many thematic songs, or maybe Halloween is just too nebulous a holiday to have a well-defined genre of music surrounding it.

Even if Halloween is centered around themes of fright, folklore, and evil spirits, the concept of fear can be hard to pin down. What we perceive as scary is largely dependent on our culture. During the Renaissance, the Church told audiences to fear unstable intervals. In the 1960's Psycho frightened its listeners with the shrill stabs of violins.

What was once scary, can in retrospect seem cliché or campy. When first popularized in film soundtracks in the 1970's and '80s, the sounds of the theremin awed audiences with its extraterrestrial sound. Now, the electronic instrument has become a cliché for setting a supernatural or unsettling mood.

Maybe it is impossible to have a concrete and well-defined genre of Halloween songs, because as sounds age, they lose their fright-factor. If the unknown frightens us while the familiar makes us nostalgic or at ease, then music aiming to frighten us has to be constantly evolving to capture our attention.

Even though I didn't expect to unlock the secret chord to capturing the spirit of Halloween, I was initially a bit disappointed in my query's inconclusive results. But perhaps there is something exciting in this uncertainty. I don't know what the next decade of frightening music will bring, what menacing musical techniques lie on the horizon. Maybe I don't need to know which intervals or timbres will make my hair stand on end, I can simply revel in the sensation of goosebumps.

Colleen Cowie runs the blog Pass The Mic.