What do you think of this fact?
An industrial robot leaves you cold. A cute toy robot is adorable. But a robot that looks almost exactly like a person? That sends a shiver down a lot of spines. This feeling has a name: the uncanny valley.
An essay hardly anyone read
The idea comes from Japanese robotics professor Masahiro Mori. In 1970, he published a short essay in an obscure Japanese journal called “Energy.” His idea: the more human-like a robot becomes, the more we like it. But just before it looks truly human, our affinity crashes into a deep valley of unease.
Mori gave examples that still sound creepy today: a realistic prosthetic hand that feels cold and limp when you shake it. Or mannequins that suddenly start moving in a dark workshop. According to Mori, movement makes the valley even deeper. With one robot at the 1970 World Expo in Osaka, simply slowing its smile to half speed was enough to make it look creepy instead of happy.
For decades, hardly anyone paid attention to the essay. An authorized English translation didn’t appear until 2012.
Monkeys fall into the valley too
Since then, researchers have actually found the valley in experiments. In a Princeton University study, scientists showed macaques real monkey faces and computer-generated ones. The monkeys looked at the almost-real fake faces for less time and quickly looked away.
A study in the journal Cognition tested 80 real robot faces. The result matched Mori’s curve: the more human, the more likable, until the robots looked almost human. Then likability dropped. Trust in a money game suffered too.
Mori had clear advice for designers: don’t try to build perfect humans, aim for moderate human likeness instead. It feels friendly without sliding into the valley.
Your brain apparently notices right away when something is almost right, but only almost.