PLOS BIOLOGYJust because robots are metal doesn't mean they're cold-hearted. In a Swiss laboratory, inch-long wheeled robots, called "artificial ants," evolved to help each other in a food task, just as predicted by a classic evolutionary rule concerning the emergence of self-sacrifice in the biological world, Wired Science reports. After searching for discs of "food," the computerized "genes" of successful robots were reshuffled and copied into a new generation of robots. Each robot was also given the option to either share their "food" reward, or hoard it. Time and again, the robots evolved to share at levels predicted by an altruism formula called Hamilton's rule, the researchers report.