I was only recently introduced to the "Uncanny Valley" concept in my Interacting in Virtual Worlds class: http://www-users.cselabs.umn.edu/classes/Fall-2011/csci5980/index.php. However, the latest Wired magazine has quite a few articles about it: http://www.wired.com/magazine/19-12.>
Basically, the Uncanny Valley theory is that the more objects or images attempt to look like people, the scarier they become. This fear is unsettling and makes people uncomfortable, preventing them from enjoying the latest technology. In fields that use computed-generated images (CGI), like movies and videogames, they are constantly evaluting where characters fall on the graph. What I discovered while reading the Uncanny Valley articles is that the same experience mirrors what I feel when I see people with plastic surgery. The look like people, but their faces move and the skin does not respond in a familiar way. Suddenly, I feel disgusted and I don't know why: Now I know it's because these expensive people have suddenly fallen into the valley.
Sadly, there is no way to return from the Uncanny Valley. Plastic surgery cannot be undone, it can only be redone in a different way. If instead the new taut skin is let age, it simply ages at a different rate than the skin around it, creating the same problem with artificial and unnatural behavior.
Here is the closest article to my thoughts above: http://www.wired.com/magazine/2011/11/pl_column_cg_perfection/