We know that rodents can learn to recognize objects, press bars and find their way around mazes. These tests are often used to study how brain conditions affect cognitive function, but they only capture a narrow window of animal cognition, says Kelly Lambert at the University of Richmond in Virginia.
They constructed a tiny car out of a clear plastic food container on wheels, with an aluminum floor and three copper bars functioning as a steering wheel. When a rat stood on the aluminum floor and gripped the copper bars with their paws, they completed an electrical circuit that propelled the car forward. Touching the left, center or right bar steered the car in different directions.