Mental Deficiency
A noted psychiatrist was a guest at a chic gathering, and his hostess naturally broached the subject in 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. “I ask him a simple question, which everyone should answer with no trouble at all. If he hesitates, that tells me just what I need to know.”
“What sort of question?”
“Well, I might ask him, ‘Captain Cook made three trips around the world and died during one of them. Which one?’”
The hostess thought for a moment, 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.”