FOLLOW THE ROBOTS: More and more, researchers are turning to robots to answer questions in animal behavior. Here, young chickens following a robotic mother shed light on the process of imprinting.COURTESY OF JOSE HALLOY, FRANCESCO MONDADA EPFL GROUPAs a PhD student at the University of Toulouse in France, Simon Garnier was fascinated by the chemical signposts used by Argentine ants—an invasive species from the Mediterranean to California—to navigate their savanna environment. As the insects traverse complex terrain, they leave traces of pheromones that other ants will then follow, reinforcing the trailblazers’ path. “In nature, they will create these big networks of pheromone trails, sort of like the road system for us,” Garnier explains. And despite their wide-ranging and convoluted habitats, the ants always seem to construct highways that carve the shortest route back to the nest from a food source. Such navigational efficiency might suggest an advanced intelligence in these tiny-brained insects. The ants, which tend to take the path with the smallest angle of deviation at each fork in a complex maze, could be computing the angles at each bifurcation. But Garnier knew there might be a simpler answer: by just trying to head straight, the ants would have a greater chance of taking the less deviant path—no complex angle measurements required.
Like any hypothesis, his idea needed to be tested. But measuring brain activity in a moving ant—the most direct way to determine cognitive processing during animal decision making—was not possible. So Garnier didn’t study ants; he studied robots. Using a small fleet of dice-size machines, rolling on wheels powered by wristwatch motors, he and his colleagues tested the robots’ ability to navigate artificial networks, using whatever computational capability the researchers programmed. A camera detected the location of the robo-ants as they moved through an arena and relayed the information to a video projector, which shone a bit of blue light just behind a trail-laying bot. As more robots moved about, the more-frequented areas glowed brighter. The robots then navigated the environment by sensing light intensity ...
