Marilyn vos Savant, who is listed in Guinness Book of World Records Hall of Fame for "Highest IQ," writes a weekly column in the Sunday newspaper supplement Parade Magazine. Her column, "Ask Marilyn," is devoted to games of skill, puzzles, and mind-bending riddles. In one issue (Parade Magazine, February 24, 1991), vos Savant posed the following question:
Suppose you're on a game show, and you're given a choice of three doors. Behind one door is a car; behind the others, goats. You pick a door-say, #1-and the host, who knows what's behind the doors, opens another door-say #3-which has a goat. He then says to you, "Do you want to pick door #2?" Is it to your advantage to switch your choice?
Marilyn's answer: "Yes, you should switch. The first door has a 1/3 chance of winning [the car], but the second has a 2/3 chance [of winning the car]." Predictably, vos Savant's surprising answer elicited thousands of critical