|The Uncanny Valley was introduced by Japanese roboticist Masahiro Mori in 1970, as a term referring to the hypothetical valley in which human-like fascimiles suddenly go from 'cute' to 'vile' with almost no warning.
For decades it has been the bane of creating realistic CG bodies and bodyparts. If you made something too real, it would not be perfect, and thus would enter into the 'so real it is creepy' dip of the valley. Typically, a less realistic body would garner a better response, explaining why so many cartoony VR forms exist - we cannot get to 'real' so cartoony has the added cute factor, to help uptake. However, the ultimate goal of creating virtual bodies that look and feel totally natural has never waviered, and would be a significant force for uptake.
The Uncanny Valley
An overview of the problem of the uncanny vallety and how increasing levels of realism fall into a dip in aesthetic levels as they become 'near human but not quite right'.
Bypassing the Uncanny Valley with Hands
In August 2008, the first hand and forearm pairing was achieved which realistically bypasses the uncanny valley for the lower arm, and allows completely realistic movement of the wrist and hand.