What is the McGurk effect?
It is a powerful multisensory illusion occurring with audiovisual speech whereby the brain can be deceived into hearing sounds that don’t exist. The effect is named after researcher Harry McGurk, who published a 1976 paper with John MacDonald titled “Hearing lips and seeing voices”.
It involves showing a person’s lips making the shape of one sound — like “bah” — while the audio is actually the person saying “fah.” What’s interesting is that your brain changes what you “hear” based on what you see. It’s “bah” all the way through, but when we see “bah” our minds transform “bah” into “fah”. It has been replicated many times and has sparked an abundance of research. It demonstrates the overwhelming influence that sight exerts over the brain and how the latter reorders perception to give us a consistent picture of the world.
