Hard-Wired for Survival.(biorobots)(Brief Article)

Gaak is one mean stage villain. Indifferent to the screams of the audience, he hoists his prey off the ground, plunges a fang into its heart and sucks out its vital energy. Without so much as a pause for remorse, he whirs off in search of fresh victims. Don't blame Gaak for this antisocial behavior. He can't help himself: he's hard-wired for survival. Gaak and other robots of his ilk are showing off their predatory instincts at the "Living Robots" show at the Magna Science Adventure Centre in Rotherham, England. "Be afraid," says the ringmaster. "Be very afraid."

The half-hour performances are intended not merely to stir the curiosity of the school kids who dominate the 500-seat auditorium, but also to advance the emerging field of evolutionary robotics. Noel Sharkey, a computer-science professor at Sheffield University, is using the contest as a Darwinian breeding ground, where the weak robots perish and the strong survive to perpetuate their kind. The idea is to build dumb robots with the capability to "evolve," leave them alone and see how smart they become. Says Sharkey: "What we are after are really simple explanations for complex behavior."

The experiment starts out simply enough. Each of the 11 robots in Sharkey's menagerie has the same goal: to obtain energy. Six of them are prey robots, who "graze" beneath a tree of white light, replenishing their batteries through solar panels. Five of them are predators who, like Gaak, can derive energy only by draining it from the "preybots." Each species recognizes the other by the amount of heat they give off, as detected through infrared sensors. The biorobots hunt and flee free of all human control, guided only by their simple "brains"--so-called neural networks that mimic the function of brain cells. To simulate evolution, Sharkey every so often picks out the most successful robots and transfers part of ...