Bar-Cohen, along with Cynthia Breazeal, has edited a book called Biologically-Inspired Intelligent Robots to further explore the possibilities for artificial muscles. He notes, however, that artificial muscles have a long way to go to become effective in robots. For instance, the rela- tively weak forces that EAP materials exert limit the strength of an artificial limb and need to be enhanced.He also admits to some doubts about the creation of highly advanced artificial beings. “I am con- cerned,” he says, “because once you release a technology you never know which way it is going to be developed.”
But he feels entirely confident about designing prosthetic devices that use artificial muscles, and holds out some dazzling speculations for the future. One type of material now under study can change both its configuration and its color under electrical stimulus, which might lead to artificial faces that not only smile and frown but also blush. And Bar-Cohen imagines putting EAP materials into a form that can be sprayed out from a special printer much as ink droplets emerge from inkjet printers. The result might be an EAP-operated butterfly printed flat onto a sheet of paper, ready for shipping, that flaps its wings and flies off when released from its box.
It’s a far cry from the ponderous walk of Gort the robot to ASIMO’s confident stride and on to the smaller motions of Kismet’s expressive face.These movements are important in the usefulness and acceptance of artificial beings, with small motions as meaningful as large when it comes to eliciting human reactions.
Successful artificial bodies, however, require more than just the right facial expression.Witness Bar-Cohen’s arm-wrestling challenge. In 1999, to stimulate researchers, he set them the task of building an arm driven by artificial muscles that could defeat a human arm wres- tler. Although this challenge has yet to be met, it is significant as a kind of Turing test for machine physicality.Turing’s original test for machine intelligence depended on verbal ability, to be judged by a machine mind’s response to queries. Isaac Asimov’s story “Robbie” presents a kind of Turing test for machine feelings, as little Gloria judges her robot to be as kind and patient as any human, through its responses to her needs. Bar-Cohen’s challenge adds another Turing-