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Facial Expression in Robots

Japanese researchers Hara and Kobayashi of the Science University of Tokyo developed a robot that showed different facial expressions, based on Ekman's system. The expressions shown in the figure are supposed to indicate (from left to right) happiness, a neutral emotion, and disgust.

A robot showing facial expressions

What were the capabilities of Hara and Kobayashi's robot?

Beauty is only skin deep

Underneath the rubberized face are 18 air-pressure driven actuators that mimic the human muscle movements of various expressions (Stone, 1996). The machine behind the face is shown to the right.

The robot not only displayed different expressions; it detected them. The robot's plastic left eye contained a scanner that fed information about light and dark areas of a face to a computer. When tested on 15 volunteer students, the robot correctly detected happiness, surprise, sadness, anger, fear, and disgust about 85% of the time. It had the most trouble with disgust, which it often confused with anger. You can see that the robot's own "disgust" expression, the third one shown above, might easily be interpreted as anger, too.

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