Love them or hate them, there’s no escaping the barrage of Christmas songs that inevitably dominate the airwaves at this time of year. While these cheesy festive melodies can’t actually drive people mad, excessive repetition can have an interesting effect on your brain and the way in which you perceive the world.
To test this out, try listening to the track in the video below, and see if you can hear Mariah Carey’s voice belting out her smash hit "All I Want for Christmas is You."
The track is a MIDI recording of the song – a format that can carry basic data such as pitch, notation, volume and velocity, but which can’t capture an actual human voice. Regardless, the video has gone viral recently, after listeners around the world became convinced that they were able to detect Carey’s famous dulcet tones on the track.
New Scientist decided to investigate this effect by seeking the opinion of Diana Deutsch, a cognitive psychologist at the University of California, San Diego. Perhaps the most amazing discovery they made was that Deutsch had never actually heard the original version of the song. Because of this, she was completely unable to detect Carey’s voice.
This lends credibility to the notion that listeners’ brains are somehow adding in the voice because they are so familiar with the track that they simply expect it to be there. Naturally, this can’t happen in those who have never heard it.
While this might sound like a failing on the brain’s part, many cognitive scientists believe that our ability to fill in the gaps in sensory information is actually a useful evolutionary trait. It’s called top-down processing, and was first proposed in the 1970s to explain how people are able to identify objects and people from just a small amount of data.
The theory states that the brain essentially hypothesizes about its surroundings from the limited sensory information it receives, thereby allowing us to perceive a full and rich world with no gaps in it. To do so, it draws on past experiences and stored information, placing present data into some sort of probable context from which it can then extrapolate.
However, since the human brain didn’t originally evolve to listen to Christmas songs on repeat, it tends to get a little confused when it can’t find Mariah Carey.
