Robots that act like rats

Robots that act like rat pups can tell scientists something about the behavior of both, according to researchers at the University of California, Davis. Sanjay Joshi, assistant professor of mechanical and aeronautical engineering, and Jeffrey Schank, associate professor of psychology, have recorded the behavior of rat pups and built rat-like robots with the same basic senses and motor skills to see how behavior can emerge from a simple set of rules.

Seven to 10-day-old rat pups, blind and deaf, do not seem to do a whole lot. Videotaped in a rectangular arena in Schank's laboratory, they move about until they hit a wall, feel their way along the wall until their nose goes into a corner, then mostly stay put. Because their senses and responses are so severely limited, pups should be an excellent starting point for building robots that can do the same thing.

Joshi's laboratory built foot-long robots with tapered snouts, about the same shape as a rat pup. The robots are ringed by sensors so that they "feel" when they bump into a wall or corner. They are programmed to stay in contact with objects they touch, as rats do. However, when the robotic rats were put into a rectangular arena like that used for experiments with the real rodents, the robots showed a new behavior. They scuttled along the walls and repeatedly bumped into one corner, but favored one wall. Instead of stopping in a corner, they kept going, circling the arena.

"When we reanalyzed the animal data, we found that the animals were also favoring one wall over another as they bumped around in corners," Joshi reports. "The robots showed us what to look for in animal studies."

The wall-following or corner-sticking is emergent behavior. That means it is not written into the computer code, but emerges as a result of the instructions the robot follows as it interacts with the environment. The team also is looking at emergent behavior from groups of robotic rats interacting using different kinds of rules. This also may demonstrate to biologists what the rats are up to.

COPYRIGHT 2005 Society for the Advancement of Education
COPYRIGHT 2005 Gale Group