Small robots re-create antlike behavior

BBC : Ants, which communicate by leaving pheromone trails, are adept at finding the shortest path between two points. Simon Garnier of the New Jersey Institute of Technology and his colleagues have reproduced that ability by using simple cube-shaped robots on wheels powered by two watch motors. The robots themselves obey only the most simple of behavioral commands: Move forward toward a target, avoid obstacles, and respond to path signals left behind by other robots. The path signals are created by a projector attached to a camera, which creates a spot of light at regular intervals along the path of each robot. Every time a robot passes through that spot, it turns to the right or the left depending on whether the light hit a sensor on the left or right side of its body, and the projector then makes the light brighter. Because the shortest path takes the least amount of time to traverse, it gets the most traffic. Over time, the result is a very bright series of lights that marks the shortest route from the start point to the target. Previous attempts at understanding ant behavior have given rise to algorithms for data routing in circuits and telecommunications. Garnier says that the robots don’t really have practical applications, but that the study shows that questions of “choice” don’t necessarily apply to ant behavior.