Nico gazes into the mirror in front of him. Looking back is his reflected self, wearing a grey Yale University sweatshirt and a baseball cap cocked at a jaunty angle. When Nico raises an arm, he recognises the arm moving in the mirror as his own.

It may not sound like much of a feat, but Nico is a humanoid robot. He has just become the first of his kind to recognise his own reflection in a mirror.

The ability to recognise your reflection is considered an important milestone in infant development, and as a mark of self-awareness, sociability and intelligence in a non-human animal. Nico's ability to perform the same feat could pave the way for more sophisticated robots that can recognise their own bodies even if they are damaged or reconfigured.

The achievement is one of a cluster of recent instances in which robots have begun to approach ...