Glossary: Uncanny Valley

The term was introduced by Japanese roboticist Masahiro Mori in 1970. He proposed that as a robot's appearance becomes more human-like, people feel increasing empathy, until a point where the likeness is close but imperfect, leading to a sharp drop in comfort—the "valley." If the robot's appearance continues to become more indistinguishable from a real human, the emotional response becomes positive once again.