|From: Ptak Science Books|
“Even if you get the surface appearance of a digital face right, the movements can do you in. As efforts to build android robots have demonstrated, manufactured blinks often seem owlish, and artificial mouths can appear to snap open too wide or too precisely. (Human lips stick together for a fraction of a second at the corners after we open them to speak.)[Masahiro] Mori’s original paper on the Uncanny Valley was more of a thought experiment than a formal study: he didn’t test his hypothesis about virtual humans on any actual humans. But the argument has been borne out in several formal studies since then. It’s not yet clear why not-quite-humans provoke so much anxiety. Maybe characters that fall into the Uncanny Valley remind us of corpses. Perhaps they flood us with uneasy intimations of soullessness. Maybe they confound the brain’s ability to distinguish what is alive and human from what is neither.
Thalia Wheatley, a neuroscientist at Dartmouth who has studied how we recognize animacy in others, told me, 'Think of horror movies—zombies, vampires, or even clowns, because they have faces painted on that don’t move. It looks like a person’s face but it doesn’t move like one. A conflict arises in the brain, which is unsettling.'”
— Margaret Talbot, The New Yorker