See here, McGurk

Sometimes, if asked, "What are you going to believe -- what I'm telling you or your own eyes?" the right answer is to punt.

For centuries, magicians have demonstrated how our eyes can deceive us.  Now there's a video on You Tube that shows just how programmed we are to fill in blanks when information is contradictory or ambiguous.  

Just looking at someone's mouth movements affects the way we hear what they are saying.

The man in the video above is saying "bah, bah, bah," but when the same audio recording is played while he mouths out "fah, fah, fah," it sounds like he is saying "fah, fah, fah."

Watch the split screen with your eyes closed when it comes up to prove it to yourself.

The phenomenon is called the McGurk effect after one of the author's of a paper that first described it back in 1976. For more, see this Wikipedia entry.

I've categorized this under politics because I have the sense magicians are not the only people exploiting the phenomenon.

A tip of the hat to my son Chris who put me on to the original video.