In 1978, the Japanese roboticist Masahiro Mori noticed something interesting: The more humanlike his robots became, the more people were attracted to them, but only up to a point. If an android become too realistic and lifelike, suddenly people were repelled and disgusted.
The problem, Mori realized, is in the nature of how we identify with robots. When an android, such as R2-D2 or C-3PO, barely looks human, we cut it a lot of slack. It seems cute. We don’t care that it’s only 50 percent humanlike. But when a robot becomes 99 percent lifelike—so close that it’s almost real—we focus on the missing 1 percent. We notice the slightly slack skin, the absence of a truly human glitter in the eyes. The once-cute robot now looks like an animated corpse. Our warm feelings, which had been rising the more vivid the robot became, abruptly plunge downward. Mori called this plunge “the Uncanny Valley,” the paradoxical point at which a simulation of life becomes so good it’s bad.