I remember once, around 7 years ago now, waiting to receive a text message from a friend on my mobile device. I had been waiting eagerly, anticipating a great hangout with a friend (a “friend” I actually happened to be quite enamored by, at the time). Buzz! Buzzzz! My phone began to vibrate in my pocket. I took it out and sure enough saw my friend’s name at the top of the screen, with the little envelope icon under it. But then something weird happened. When I opened the mail, it wasn’t from this friend at all, but from another acquaintance. Confused, I checked the sender’s name again. Sure enough, it was not the girl I had a crush on. How did I see her name on the message when it arrived!?! The answer? I had wanted to, and expected to. I hallucinated my own “reality”!
The same can happen with sound. Watch the video at the top and close your eyes. You will hear the sounds “ba ba, ba ba.” Now open your eyes. Watch the video again. You will hear ”da da, da da.” Why? Because the actually silent video shows a man mouthing the shape of the sound “da,” while the actual audio track of the video is the sound “ba.” Your brain gets confused by the two signals and attempts to reconcile the audio with what it looks like the man is saying. Welcome to the matrix!