McGurk Description

The McGurk effect is an auditory illusion which results from combining a face pronouncing a certain syllable with the sound of a different syllable. The illusion is stronger for some combinations than for others. For example, an auditory 'ba' combined with a visual 'ga' is perceived by some percentage of people as 'da'. A larger proportion will perceive an auditory 'ma' with a visual 'ka' as 'na'.

These movie clips demonstrate both versions of the effect. The actor will say a series of syllables very quickly. Focusing on the actor's mouth may enhance the illusion.

Technical notes:

  • The files are fairly large, and will take some time to download. The smaller images have smaller image sizes.

  • When playing the clips, the coordination of picture and sound is important; if the image skips frames (ie, looks unnatural), try quitting other applications to reduce processor load.

  • If possible, enlarge the image and set the video to repeat in a loop.

  • The .avi versions are suggested for Windows systems, the Quicktime .mov versions for Macintosh. (Of course, players are available for most combinations.)

  • Movies
    Ma-Ka (Strong) version Ba-Ga (Weak) version
    Smaller image .avi [.9 MB]
    .mov [3.5 MB]
    .avi [.8 MB]
    .mov [2 MB]
    Larger image N/A .avi [3.8 MB]
    .mov [6 MB]