»The Uncanny Valley«
from wikipedia from wikipedia (wikilink):
The uncanny valley hypothesis holds that when robots and other facsimiles of humans look and act almost like actual humans, it causes a response of revulsion among human observers. The “valley” in question is a dip in a proposed graph of the positivity of human reaction as a function of a robot’s lifelikeness.
It was introduced by Japanese roboticist Masahiro Mori as Bukimi no Tani Genshō (不気味の谷現象) in 1970, and has been linked to Ernst Jentsch’s concept of “the uncanny” identified in a 1906 essay, “On the Psychology of the Uncanny”. Jentsch’s conception is famously elaborated upon by Sigmund Freud in a 1919 essay titled “The Uncanny” (”Das Unheimliche”). A similar problem exists in realistic 3D computer animation, such as with the films Final Fantasy: The Spirits Within, The Polar Express, and Beowulf.