The Uncanny Valley of Robotics
The “uncanny valley” is a term coined by roboticist Masahiro Mori in 1970 to describe a very odd phenomenon. He observed that totally non-human robots (think Wall-E, or assembly-line robots) are appealing to people, and regular humans or very convincing robots are pleasant as well. Most robots that fall in the middle appear pretty harmless too. But robots that are just on the verge of looking like a humanoid creep people out, big time. That range - clearly not a robot, but not quite human - is called the Uncanny Valley. There’s been a ton of interesting research about the uncanny valley, including the finding that movement enhances the response (makes robots more empathetic, makes pseudo-humans much creepier). Additionally, there have been a bunch of proposed evolutionary reasons for why we find a not-quite-likeness so threatening. Personally, I just love this graph: 
