R rated movies edited for television often use the McGurk effect to cover up profanity. Instead of the swear word they record the actor's voice saying "asp" or "fudge" over the real swear words and it looks like the lips are pronouncing the same words. Kinda like watching the old Godzilla movies where the lips are not moving in sync...but its not as obvious when this effect is used. They call it an auditory illusion. Check out this link for a video example and explanation of how this effect works

Last update: 12:39 PM Tuesday, December 12, 2006