The McGurk Effect

In this Audio-Visual illusion called the "McGurk Effect" what one person sees and hears conflicts. Due to conflicting stimuli, our brain tries to make a coherent result out of the different sensations. What we see overrides what we hear even if we are fully aware of how the illusion works. When the voice of the illusion consistently says "ba" but the video changes to the mouthing of the word "fa" we cannot help to hear "fa". However, when you close your eyes you can hear "ba" again, and by putting the two videos ("ba" and "fa") next to each other, you can actually trick your own brain into switching back and forth between what you are perceiving. It's remarkable to see your brain override itself to the point where you cannot control what you hear even though you are hearing something different.