The wise men puzzle is based on a story. A king is choosing a new advisor and gathers the three wisest people in the land. He promises the contest will be fair, then puts either a blue or white hat on each of their heads and tells them all that the first person to stand up and correctly deduce the colour of their own hat will become his new advisor.
Selmer Bringsjord set up three robots. Two were prevented from talking, so all three were asked which one was still able to speak. All attempt to say “I don’t know”, but only one succeeds – and when it hears its own voice, it understands that it was not silenced, saying “Sorry, I know now!”
For a robot to pass the test it has to listen to and understand the question, then hear its own voice saying “I don’t know” and recognise it as distinct from another robot’s voice, then connect that with the original question to conclude that it had not been silenced.
Details about how the robots passed, and what sort of programming was used has not been released yet. Bringsjord’s work will be presented at the RO-MAN conference in Japan, which runs from 31 August to 4 September 2015 so we will probably know then.