Growing up, we’ve been amazed by optical illusions such as magic eye and made sick by things like 3D movies. But it’s one thing to question our eyes, a whole other thing for us to question our ears.
Yes, just like there are optical illusions, did you know there are acoustical illusions too? Prepare your mind for what’s about to come.
Below we’ve embedded an acoustical illusion. Put on a pair of headphones, or turn your speakers up so your whole office can hear, and press play on the video. It should replay automatically, if it doesn’t keep pressing play on the video when it finishes.
See how the pitch in the audio keeps going up with every play of the video? Except of course, it actually doesn’t. Our ears just think it does.
So how does it work? According to the Huffington Post and the evil genius behind this video, the trick is called the Shepard Tone after it was discovered in 1967 by cognitive scientist Roger Shepard.
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“When a number of octave notes are played at the same time, the average human ear will simply hear the one note, closest to the last pitched sound it heard, as opposed to differentiating and splitting that sound into its singular octave parts,” user maricv 84 writes.
“The volume of the higher pitched tone slightly decreases and the lower pitched one increases over the scale, which is what makes the effect seem so seamless.”
So basically, as the video goes on the lower tone is getting louder and the higher tone is getting softer; which tricks your brain into switching with part of the sound it’s actually paying any attention to and makes it sound like the notes are continuing to increase in pitch.
Mind. Blown.
