In the early 1970s Americans had experienced gasoline shortages owing to the OPEC oil embargo. So, when Johnny Carson made a joke about a shortage of toilet paper on "The Tonight Show," rolls of toilet tissue began disappearing off store shelves as nervous consumers hoarded the prized commodity, thereby creating a genuine shortage. Mo Rocca talks with documentary filmmaker Brian Gersten and Boston University economics professor Jay Zagorsky about the real-world implications of a joke.
