In aesthetics, the uncanny valley is a hypothesized relationship between the degree of an object’s resemblance to a human being and the emotional response to such an object. The concept suggests that humanoid objects which imperfectly resemble actual human beings provoke uncanny or strangely familiar feelings of eeriness and revulsion in observers. “Valley” denotes a dip in the human observer’s affinity for the replica, a relation that otherwise increases with the replica’s human likeness.
Examples can be found in robotics, 3D computer animations, and lifelike dolls. With the increasing prevalence of virtual reality, augmented reality, and photorealistic computer animation, the “valley” has been cited in reaction to the verisimilitude of the creation as it approaches indistinguishability from reality. The uncanny valley hypothesis predicts that an entity appearing almost human will risk eliciting cold, eerie feelings in viewers.
The concept was identified by the robotics professor Masahiro Mori as bukimi no tani genshō (不気味の谷現象) in 1970. The term was first translated as uncanny valley in the 1978 book Robots: Fact, Fiction, and Prediction, written by Jasia Reichardt, thus forging an unintended link to Ernst Jentsch’s concept of the uncanny, introduced in a 1906 essay entitled “On the Psychology of the Uncanny”. Jentsch’s conception was elaborated by Sigmund Freud in a 1919 essay entitled “The Uncanny” (“Das Unheimliche”).