THE GHOST OF MARIAH CAREY

PROF. DIANA DEUTSCH

This video on the left caused a stir when it was posted on Tumblr before Christmas. It's Mariah Carey's version of All I Want For Christmas I You, converted to MIDI, which is a digital way of recording sound. MIDI sequencing makes the song sound like the music to a cheesy '80s video game and removes the human voice. Or does it? Lots of listeners contacted the blog to say they could hear Mariah's ghostly voice, singing along in the background. Can you?

It gets odder. The file was passed on to Diana Deutsch, a cognitive psychologist in California, and she listened to it and heard... nothing! Ah, but Prof. Deutsch had never heard the original version, you see.

The "ghostly Mariah" is an example of top-down processing. This is where the brain uses information it already has as a sort of "template" to understand the world around it. So, if you've heard the song before you have a template for how it's supposed​ to sound and your brain uses that to "fill in the gaps" in the MIDI version you're listening to.
​
This is why some people can hear the non-existent vocals but others can't; their expectations shape their perceptions.

It seems like the brain abhors ambiguity and wants to make sense out of things, so we create for ourselves precepts of things that aren’t really there
​- Prof. Deutsch

SOME MORE AUDITORY ILLUSIONS

​You can try some other examples of MIDI songs to see if you hear the ghostly vocals too. The video on the left has a MIDI version of Stayin' Alive by the Bee Gees, followed by a clip of the real version; it also has songs you may not know, like Piano Man by Billy Joel, followed by the real versions. Do you hear the vocals in some but not others?

Or try the clip below it. Some people claim to hear Satan-worshipping lyrics when they play Led Zeppelin's Stairway To Heaven backwards. It gets much easier to hear the non-existent words when you've been "primed" - if you know what words you're expected​ to hear. Then you seem to hear them loud and clear!

Hopefully, you'll make a connection here to some psychology from the course, because "top-down processing" sounds a lot like schemas. Both of them are about having your perceptions shaped by your expectations. Schemas cause people to remember things the way they expect them to be, rather than the way they actually were. If you can hear a non-existent voice of Mariah Carey, then you can imagine how your mind can trick you into remembering something that didn't really happen.