Uncanny Valley

That's why zombies are scary.

"These were robots in human form with distorted faces, and they gave my daughter nightmares. When I asked her why she was frightened of the Cybermen but not of the Daleks, she replied that the Cybermen looked like terrible human beings, whereas the Daleks were just Daleks."
Ann Lawrence, writer for The Morning Star on Doctor Who: The Tomb of the Cybermen

In 1970 Japanese roboticist Masahiro Mori proposed in The Uncanny Valley that the more human a robot acted or looked, the more endearing it would be to a human being. For example, most lovable Robot Buddies look humanoid, but keep quirky and artistically mechanical affectations. However, at some point, the likeness seems too strong and yet somehow, fundamentally different—and it just comes across as a very strange human being. At this point, the acceptance drops suddenly, changing to a powerful negative reaction. The Uncanny Valley doesn't necessarily have to invoke fear though; for some people, the reaction is more similar to Narm or unintentional comedy. Either way, you don't feel the same about that character as you would a human, or even something less realistic.

If shown as a graph (like the one to the right), the acceptance on the Y axis and increasing X approaching human normal, there is a slow rise, then a sudden drop, then a sudden peak as "human normal" is reached. Masahiro Mori referred to this as the "uncanny valley". This video explains it extremely well.

Thus, things that look somewhat human, but are clearly not — such as C-3PO (in Star Wars) or a Golem — produce an accepting reaction, while things that are very nearly human, but just a little strange — such as a child's doll, a ventriloquist's dummy, or a clown — produce a negative response. For some people, the resonance is stronger with a moving object, which is why a corpse is creepy but a moving corpse is creepier still. In fact, some people that don't have a problem with things like zombies and consider them merely another monster may still be creeped out by things like unnatural movement.

This may also apply to sound as well. For example, a voice speaking words, but at a higher or lower pitch than is humanly possible, or a recording of a human voice, but played backwards. Or maybe a computer voice like Microsoft Sam. Though some people just find the effect comical and/or silly.

In recent decades this trope has applied to film CGI and video-game graphics, as technology has developed over time to allow for more photorealistic graphics, but not necessarily realistic movements. It's become very easy for computers to simulate textures and skin tones, but convincing movement and facial expressions aren't so simple, often requiring Motion Capture to look realistic. More stylized 3D models or a 2D art can generally get away with odd animations or expressions, but the more realistic the graphics shoot for, the more noticeable it is when something isn't lining up with reality. This is normally a cost issue, as detailed animation can be extremely time-consuming to craft and even more so when one set of animations is used for multiple characters and still needs look natural for all of them. Not putting in enough effort can produce the effect where a character can come across as a something less than human, like a zombie.

For one notable example, the critically acclaimed L.A. Noire received special recognition for its high-quality facial motion capture, allowing for the gameplay to focus heavily on reading the expressions of witnesses and suspects for the purposes of interrogation. However, because the engine only provided this level of detail in faces while human bodies were unnaturally stiff and jerky, many critics also cited being unnerved by the obvious dissonance between the active and alive faces and the rod-still bodies.

Many cartoons nowadays prefer a simultaneously stylized yet simplified character design, versus the realistic look amongst some older cartoons. In the latter, it's more obvious the budget just didn't allow characters to move much. Heavily rotoscoped characters also often seem less real than more stylized animated characters, especially when they're in the same production. See the Fleischer Studios version of Gulliver's Travels for an example.

The psychological reasons behind the Uncanny Valley reaction are unknown, but seem to be rooted in human evolution. Under one theory, a thing that appears human, but moves unnaturally or herky-jerkily, is interpreted by the viewer's brain as a terribly damaged human and is thus unfit for mating. Hence the natural instinctive response is revulsion (compare to the reaction of seeing a person with a missing limb or feature). Another theory holds that the response is a vestigial reaction to what is perceived by the brain to be a predator's disguise or lure, which triggers a "threat" response.

Rather unfortunately, this trope can be applied to real life people and may be in part an explanation (though not an excuse) for things like racism when other groups of people inspire this reaction in certain people. People with social disabilities tend to be hurt hardest by this reaction, as people usually don't try to see past the "unnatural" behaviour of the individual and may have the same negative reaction that this trope describes.

This trope can also be used purposely, to make something creepy when creepiness is called for. Some examples of particular ways to produce this effect are listed under Creepily Long Arms, Creepy Long Fingers, Malevolent Masked Men, Body Horror and Uncanny Valley Makeup.

See also Reality Is Unrealistic, where the poor impression comes less from being "creepy" as from breaking existing conventions which audiences had come to expect. In addition, there's Off Model, Bishonen Line, No Flow in CGI, and Ugly Cute. And while you're at it, see What Measure Is a Non-Cute?, as the scientific study of that trope gave birth to this one. An opposite is Eldritch Abomination, where the unsettling effect is caused by being way too unfamiliar rather than being way too human, yet still produces the same abominable effect (although the two can overlap as a Humanoid Abomination). Furries Are Easier to Draw is a way artists get around the Uncanny Valley phenomenon; it's easy for drawn humans to to dip into the valley, but a cartoony talking animal doesn't evoke the same response.

This should not be confused with the 5th anniversary of That Guy with the Glasses, which was named after this phenomenom, but had little to do with it.


Alternative Title(s):

Nightmare Valley