The "uncanny valley" is a hypothesis that as a robot is made more humanlike, the emotional response from a human being to the robot will become increasingly positive and empathic, until a point is reached beyond which the response quickly becomes that of strong repulsion. The phenomenon can be explained by the notion that, if an entity is sufficiently non-humanlike, then the humanlike characteristics will tend to stand out and be noticed easily, generating empathy. On the other hand, if the entity is "almost human", then the non-human characteristics will be the ones that stand out, leading to a feeling of "strangeness" in the human viewer.
