TRUE STORY:

A noted psychiatrist was a guest speaker at an academic function where Nancy Pelosi (Speaker of the U.S. House of Representatives at the time) happened to appear. Ms Pelosi took the opportunity to schmooze the good doctor a bit and asked him a question with which he was most at ease.

'Would you mind telling me, Doctor,' she asked, 'how you detect a mental deficiency in somebody who appears completely normal?'

'Nothing is easier,' he replied. 'You ask a simple question which anyone should answer with no trouble. If the person hesitates, that puts you on the track..'

'What sort of question?' asked Pelosi.

Well, you might ask, 'Captain Cook made three trips around the world and died during one of them. Which one?''

Pelosi thought a moment, and then said with a nervous laugh, 'You wouldn't happen to have another example would you? I must confess I don't know much about history.'