On: The McGurk Effect - An Illusion you will never overcome.

[iam]

Looks like he's biting his lip in the left video, but not in the right video. I thought it was supposed to be identical except for contrast?

[humbledrone → iam]

If you'd like to understand the video, I would suggest watching it. It contains a thorough description of what it's about, including why the man's lips have a different shape in the left-hand image.