Uncanny Valley: Encyclopedia II - Uncanny Valley - Effects of movement

Uncanny Valley - Effects of movement

For creatures, including robots, movement is generally a sign of life. As shown in the figure above, adding movement changes the shape of the uncanny valley by exaggerating the peaks and valley. For the industrial robot, the impact of movement is relatively slight because we see it as just a machine. If it stops moving, it just stops working. But if programmed properly to generate humanlike movements, we can enjoy some sense of familiarity. Humanlike movement requires similarity of velocity and acceleration. Conversely, if we add movement to a prosthetic hand, which is at the bottom of the uncanny valley, our sensation of strangeness grows quite large. Some readers may know that recent technology has enabled prosthetic fingers to move automatically. A commercially available prosthetic hand made with the highest technique was developed in Vienna. To explain how it works, the intention to move the forearm, even if missing, produces current in the arm muscles that can be detected by an electromyogram. So the prosthetic hand detects the current by means of electrodes and amplifies the signal to activates a small motor in the prosthetic arm to move the fingers. This hand can move in a way that causes some healthy people to feel uneasy. If you shook a woman's hand with this hand in a dark place, the woman must be shocked!

Since these effects are apparent for just a prosthetic arm, the strangeness will be magnified if we build an entire robot. You can imagine going to a work place where there are many mannequins: if a mannequin started to move, you might be shocked. This is a kind of horror.

In the World Expo held in Osaka this year, the robots displayed a more elaborate design. For example, one robot has 29 artificial muscles in the face to make humanlike facial expressions. According to the designer, laughing is a kind of sequence of face distortions, and the distortion speed is an important factor. If we cut the speed in half, laughing looks unnatural. This illustrates how slight variations in movement can cause a robot, puppet, or prosthetic hand to tumble down into the uncanny valley.

Adapted from the Wikipedia article "Effects of movement", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki