It's a simple fact of the holiday season: Christmas isn't about a tree, or presents, or family. Christmas is about Mariah Carey.
It's been two decades since the pop diva released "All I Want for Christmas Is You," and in the time since, the song has become an inescapable staple of the season. Each year, despite the release of more and more Christmas songs, we always return to the same one. Will there ever be a time when we get sick of it?
According to science, probably not.
In a 2007 study of our brains, researchers examined how people felt while listening to excerpts of popular music they had heard in the past. If a song was playing during any big first — a kiss, a college party — that song will later cause certain brain regions, including the medial prefrontal cortex, which is integral for retrieval of long-term memories, to light up, essentially transporting you back to that moment.
Essentially, the science suggests that "All I Want for Christmas," or any other holiday music, may make our brains high on nostalgia.
"Music is such a strong stimulus," said Megha Sharda, a researcher at the International Laboratory for Brain, Music and Sound Research at the University of Montreal. "Most people have positive associations with holiday music ... so when you hear it, the brain releases hormones that give us pleasure, same as when we eat chocolate, which reinforces the memory, making the positive association stronger.”
Christmas music may also spark positive feelings based on experiences burned into our brains that we don't consciously remember. In a 2013 study, psychologists discovered that people preferred music that was popular when they came of age and music from their parents' heyday, which was probably playing during happy moments in participants' childhoods, even if they didn’t explicitly recall it
As Pacific Standard reported, "The researchers report that the presence of personal memories associated with specific songs was 'closely related to whether they made participants feel happy or energized.' This suggests we're not responding so much to the music per se, but rather to the events and feelings it triggers in our brains."
Once you feel connected to a song, hearing it more only intensifies the love. Songs we like activate the brain's "default-mode network," which is involved in self-aware, "mind-wandering" thinking, like imagining the future. But listening to our favorite songs, according to a study recently published in Nature, has the added effect of increasing connectivity between sound-processing regions and the hippocampus, which is involved in memory and social emotion. Basically, songs we like provoke thoughts, but songs we love also give us the feels.
Furthermore, "All I Want for Christmas Is You" may excite our brains in large part because we know every word of the song. Neuroscience research shows that we get more pleasure from familiar songs than unfamiliar songs (whether or not we claim to like them). In a 2011 study of self-described "music lovers," cognitive scientists from Johns Hopkins University used fMRI (functional magnetic resonance imaging) to observe neural responses to popular songs. Hearing familiar songs sparked activity in the reward networks and emotional processing areas of participants' brains, regardless of their opinions of the songs.
The nostalgic high we get, paired with the increasing joy we feel every time the song floods our ears, points to one thing: "All I Want for Christmas Is You" isn't going anywhere, and you're going to be absolutely fine with it.