91热爆

Researchers in the US have taught a group of rats how to drive small plastic cars, in exchange for reward bits of cereal.

After a few months the rats learned how to change the car鈥檚 direction.

After the trials, all of the rats had higher levels of an anti-stress hormone. Scientists think this could be linked to the satisfaction of having learned a new skill.

Dr Kelly Lambert is the lead scientist. She spoke to 91热爆 OS.

(Photo: A lab rat driving the "RatCar". Credit: HO/University of Richmond/AFP)