Uncanny Valley

The more human a robot looks, the more likeable it is — until it looks almost, but not quite, human, which feels unsettling.

This hypothesis was proposed in 1970 by Japanese roboticist Masahiro Mori in the Japanese magazine Energy, under the original title “Bukimi no Tani Genshō.” He described it with a curve plotting affinity against human likeness: the more human-like a robot is, the more people warm to it, but once its appearance gets very close to a real person while still having subtle flaws, affinity plunges sharply into revulsion, forming a “valley” — only once a robot becomes indistinguishable from an actual human does affinity rise again. He also noted that movement amplifies this effect. The implication for humanoid design is to either stay clearly “non-human,” mechanical-looking or cartoonish, or be equally realistic in every dimension, avoiding a mismatch such as lifelike skin paired with stiff, robotic expressions. IEEE Spectrum published an authorized full English translation of the original essay in 2012.

ExampleMori's own example: a finely crafted prosthetic hand can look very realistic, but the moment you shake it and feel it is cold and limp, a sudden sense of unease sets in.

Related

Humanoid Robot · Hyper-Realistic Humanoid Robot · Human-Robot Interaction · Engineered Arts Ameca · Sophia (Hanson Robotics)

Sources

The Uncanny Valley: The Original Essay by Masahiro Mori (IEEE Spectrum)
Uncanny valley – Wikipedia