Way back in 1919 Sigmund Freud postulated his concept of the uncanny. In the (cleverly named) The Uncanny, Freud explored a problem of aesthetics—when something is both familiar and unknown the experience of viewing it can be strongly unsettling. Fifty years later, roboticist Masahiro Mori presented his own work on the uncanny. Drawing heavily on his predecessor's work, Mori developed his "uncanny valley" hypothesis.