Music can influence and even improve your mood, and certain songs can trigger specific emotions. “Music is often encoded in a very personal and emotional way, and we know that when we encode anything with emotional or personal connotations, it’s recalled better in memory,” music psychologist Vicky Williamson, who is an expert on memory, told the BBC.
That’s why a song from your high school years may be indelibly burned in your brain alongside a mental image of your teenage crush. Hearing that song even decades later can instantly bring back all of the lyrics, along with a flood of old emotions.
Then there’s the simple fact that we hear popular songs far more than we realize: in shopping malls, elevators, fitness classes, restaurants, and bars; at parties and weddings; on the radio; in advertisements; and in the soundtracks of television shows and movies. Each time, the lyrics are reinforced in our brains.
And a song’s chorus gets repeated even more times. Anyone who has ever visited a shopping center in December — even someone who doesn’t celebrate Christmas — can probably sing the chorus of “Jingle Bells.”
Regarding earworms specifically, neuroscientist Daniel Levitin explained to The Naked Scientists that “they tend to be simple melodically and rhythmically.”
He added: “They tend to be the kinds of songs that the popular radio stations play and overplay. So they get stuck in there and you can’t get them out. Most people aren’t running around with Stravinsky in there, they’ re running around with ‘Who Let the Dogs Out?'”