You have heard the theme from the TV show Batman haven't you? If you haven't listen here. Now tell me, do you hear singers singing "Batman" or do you hear horns playing " ba baaa"?

Quite often what you think you are hearing or what you are looking at is what your brain will tell you that you are hearing. This is called the McGurk Effect.  As you watch this video look at the pictures and listen to the audio. It seems to magically change to fit the picture when it is in fact the same audio all the way through the clip.