HE pearly white humanoid watches placidly as the woman moves a toy brick sitting on the table. Inside, iCub's imagination is running wild.

The robot is being tested for its ability to track the mental states of others. Known as theory of mind this gives humans many sophisticated traits, including empathy and deception Robots have demonstrated theory of mind before but iCub is different. Last week, at the Living Machines conference in London, researchers revealed that it is the first robot to acquire theory of mind without specific programming.