The Uncanny Valley

This Science of YouTube video explains the uncanny valley. This theory, first introduced by Masahiro Mori in 1970, proposes that things that look and act too much like humans can seem creepy.

The clip shows some familiar robots from films and animation.

How does our brain perceive each of these images? Why is it that we have a different reaction to each of them? How do some of the more advanced creations conflict with our mental image of what a human is?