Dan’s Robot Double post reminded me of one of my new favorite terms, “The Uncanny Valley.” It’s a hypothesis that humans have an instinctive response of revulsion to facsimiles of themselves. The “valley” is based on the idea that if you encounter a very crude and not-really-that-human-like robot, you are OK with it, but at a certain point as it gets too close to human-like, you have a response of revulsion that can be graphed as a dip or “valley” (and then you get out of the valley, presumably, when it becomes so real that you can’t tell the difference).
So in the handy chart above, industrial and even “humanoid” robots are fine, as are stuffed animals, “healthy persons,” and “bunraku puppets” (whatever that is) — but corpses, zombies, and prosthetic hands all fall within the Valley. These examples all seem to conjure up images of death, which may be what it’s all about — or maybe an instinctive fear of being replaced by robots? Anyhow, Dan’s robot doubles would surely have to contend with the Uncanny Valley as they went about their masters’ business.
More here, including a laundry list of possible explanations, with both the fear of death possibility alluded to above and some other interesting ones.