Animation and the Uncanny Valley

I recently became aware of a name for something that many of us as artists have seen, experienced and possibly even fought against. It is called, "The Uncanny Valley" As defined on Wikipedia:

"The uncanny valley is a hypothesis that when robots and other facsimiles [CG Characters!] of humans look and act almost like actual humans, it causes a response of revulsion among human observers. The "valley" in question is a dip in a proposed graph of the positivity of human reaction as a function of a robot's lifelikeness. It was introduced by Japanese roboticist Masahiro Mori in 1970. A similar problem exists in realistic 3D computer animation, such as with the films The Polar Express, and Beowulf."

Mori's hypothesis states that as a robot [CG character] is made more humanlike in its appearance and motion, the emotional response from a human being to the robot [CG character] will become increasingly positive and empathic, until a point is reached beyond which the response quickly becomes that of strong repulsion. However, as the appearance and motion continue to become less distinguishable from a human being, the emotional response becomes positive once more and approaches human-to-human empathy levels.

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 (think of how we anthropromorphize automobiles or other inanimate objects; giving them faces etc). 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. In other words, a robot stuck inside the uncanny valley is no longer being judged by the standards of a robot doing a good job at pretending to be human, but is instead being judged by the standards of a human doing a terrible job at acting like a normal person.

So, with thanks to my friend Tom St. Amand, I wanted to discuss how the Uncanny Valley impacts us as CG animators and as portrait painters and as
artists in general.

First, let me list things that put our more realistic CG characters into the "Uncanny Valley."

- Lack of eye jitter (small, darty movements of two or three frames when someone is looking at something).

- Crossed eyes, or wall-eyed eyes; these eyes generally appear to be
unfocused (think of wax dummies of famous people, if they don't focus the eyes, the uncanny valley swallows them up). Actors need an eyeline.

- Wavering focus of the eyes; eyes not looking at a consistent target.

Under this, I would put actors looking like they are reading from cue
cards. Or, not looking at another actor when speaking to them at a moment when we would expect them to be. Wavering eyes can also appear to be a sign of inebriation or brain damage.

- Eyes that look like a doll's eyes, or that have the texture
of a dolls' s eyes; eyes that read as glass eyes.

- If the eyes always move with the head when the head rotates, it looks

robotic. Put in eye tics to lead the head rotation.

- Lip Sync is off. Look how off-putting a bad dub job can be on a live
action film.

- A perceived slackness in the face.

- When the face moves in a robot-like, mechanical way or when the different parts of the face look uncoordinated.

-When characters don't blink at all, it looks odd. The average person blinks once every five seconds.

- When your character makes an "out of character" expression, it looks disturbing (as it can be in real life). If Jerry Lewis crosses his eyes in a film, it can be seen to be part of his character. If Dean Martin does it, it seems weird.

- People are made comfortable when you show them what they expect.

- Unnatural skin color or texture. Mottled skin (actors usually wear makeup to hide mottled skin to make it look more pleasing and 'natural' on camera)

- "Unnatural" lighting; an actor won't usually be lit to look bad, unless they are playing someone sinister.

- Don't be so in love with reality that you make your character look sick. Think how he would look if he were an actor/real person in your movie.Would you play up his flaws?

- Changes in facial expression that seem too slow, or are late.

- Facial features that are mirror-imaged; a lot of people have one side of their face smaller than the other. Features that seem too "perfect".

- Movement on one side of the face only; this looks like you have had a
stroke.

- Facial movement that seems uncoordinated with what the body is doing.


So, how do we get our characters OUT of the "Uncanny Valley"?

- Think about micro expressions; fleeting changes of expression.

-Nostril flares and raises.

-Brow and cheek raises.

-Changes in volume in the cheeks (like cheek blow).

-Make sure 'sticky lips' are in there if that is available on your rig.

- Be careful when moving facial shapes in isolation.

-Make lip shapes for consonants, etc. simple and readable.

- Don't over-enunciate. More cartoony characters can sometimes get away with this.

- Don't forget swallows, gulps and neck tightens.

- Some people's heads shake and bob involuntarily instead of moving in a "key-framey" fashion. Don't just leave the head static. Try to break the regularity of even movements.

- When we blink, sometimes the brows come down, the the lower lids scrunch up. Also, the cheeks can raise up to "meet" the blink.

- People also squint and half-close their eyes; their eyes can narrow and remain so without fully opening again.

- Look for places to widen or flare the eyes.

-Eyelash flutter; lids don't always close all the way down.

-Eye twitches (lids and the areas above and under the eyes)

- The Jaw can move side to side and in and out as well as up and down.

- Lips sometimes stick to teeth when we talk (dry lips)

-Don't forget breathing (chest rise and fall)

-Get the tongue animation in there!

-If you character looks like a Zombie, try and figure out why. Sometimes even a live actor's performance is criticized for having no "spark."

- Offset raising and lowering of the brows occasionally, instead of both at the same time.

- A smile will generally raise the cheeks.

-A smile should be reflected in the EYES as well as the mouth.

Paul Ekman:

-In a fake smile, only the zygomatic major muscle (cheek muscle) which runs from the cheekbone to the corner of the lips, moves.

-In a real smile, the eyebrows and the skin between the upper eyelid and the eyebrows come down very slightly.

- Teeth and the inside of the mouth should look wet.

- Think of all the actors/actresses who have had botox or face lifts, who
then don't look like themselves anymore. Part of their faces looks "frozen."

- In a squint, the area UNDER the yes moves too, not just the lower lids.

-Make sure the expression fits the voice

These are just some of the ways that you can create more realistic characters whether they are CG or portrait paintings. Hopefully, some of the things on this list will allow you to stay out of the Uncanny Valley with your
performances or renders.

Best wishes and happy animating!

Guest Blogger Keith Sintay