The Uncanny Valley is the notion that when robot or animated people seem
Published in the Oxford University Press journal Social Cognitive and Affective Neuroscience, the functional MRI study suggests that what may be going on is due to a perceptual mismatch between appearance and motion…According to their interpretation of the fMRI results, the researchers say they saw, in essence, evidence of mismatch. The brain "lit up" when the human-like appearance of the android and its robotic motion "didn't compute."
"The brain doesn't seem tuned to care about either biological appearance or biological motion per se," said Saygin, an assistant professor of cognitive science at UC San Diego and alumna of the same department. "What it seems to be doing is looking for its expectations to be met – for appearance and motion to be congruent."
In other words, if it looks human and moves likes a human, we are OK with that. If it looks like a robot and acts like a robot, we are OK with that, too; our brains have no difficulty processing the information. The trouble arises when – contrary to a lifetime of expectations – appearance and motion are at odds.