THE REAL HISTORY OF ARTIFICIAL BEINGS
Maintaining that delicate balance is not easy. One recent animatronic model of a human head is packed to the very skin with a dense collection of components and wires, including 22 small motors that control its movements and facial features.
Along with flexible mechatronic design, these robots use materi- als that replace the substances once incorporated into eighteenth- century automata. Glass eyes were first made in Venice around 1579, but have been replaced by plastic versions that look more natural. Likewise, although prosthetic limbs, from wooden legs to iron hands, have a long history, they began to look convincing only with the arrival of silicone rubber, a compound with natural-feeling resilient properties. It can be used to form an artificial skin with layers that approximate the internal structure, and therefore the feel, of real skin, it can be colored as desired, and pores and hair can be added as final persuasive details.
These and other advances are leading simultaneously to improved prosthetic devices and to the possibility of androids whose internal structure is overlaid with an artificial humanlike outer layer—modern versions of eighteenth-century automata. Like the rubber in de Vauconson’s duck that simulated the digestive tract, some of the inter- nal machinery functionally replicates what goes on in living creatures; for instance, by using “smart materials,” which change their properties under external control. One type can be made to extend and contract depending on electrical voltage, simulating how human muscles act. The result is a synthetic muscle that can give artificial limbs a smooth, natural action, rather than the jerkier motion produced by machinery.
Such humanlike flexibility opens up possibilities for convincing bodily motion and even facial expression. For instance, the Saya robot at the Tokyo University of Science has a humanlike face with sili- cone-rubber skin. Underlying this is a set of artificial muscles, worked by compressed air and arranged to follow human facial anatomy, that can be manipulated to display joy,anger, astonishment,and other emo- tions. Although the question whether artificial beings can or should experience emotions is complex, there is no doubt that the ability to simulate emotion through facial expression and body language greatly affects interactions with people.