Neurons Firing and the storm beneath it all. [via]

The McGurk Effect

The McGurk effect is an illusion that occurs when the brain is giving conflicting information, a sound is paired with the visual component of another sound, resulting in the perception of a third sound. This demonstrates an interaction between hearing and vision in speech perception.

As Professor Lawrence Rosenblum explains, no matter how aware you are of the McGurk effect, your brain will always be fooled.