I disagree that it is an English parsing problem. It is a logic parsing problem. Though, it would be great to poll people in other languages to try to verify if

I disagree that it is an English parsing problem. It is a logic parsing problem. Though, it would be great to poll people in other languages to try to verify if language or culture affect how people approach the problem. It is a logic problem because people tend to look at one part of the problem instead of the whole. They see a door taken from the pool of choices, now seeing two doors, they jump to the idea that it is 50/50. If they approach it as a simulation, it becomes clearer. A related question: if I have two children, and one is a boy, what is the probability the other is a boy? Got your answer? Most people, just like in the Monty Hall problem, get it wrong. If you run the simulation of options, it is clear. The options are BB, GB, BG (the option GG does not exist). So the answer is 1/3. Even seeing this, many folks have a mental block and want to say that the independent act of the other child is a given gender is still 50/50, which, ignoring the information already given in the scenario, would be true. Back to Monty Hall. Your choices are between C, G1, and G2. Your starting position can be any of those. C -> G1 or G2 is shown G1 -> G2 is shown G2 -> G1 is shown In two of those situations, the car has not yet been picked, so you have a 2/3 chance of picking the car if you switch your door choice after the goat reveal. People tend to think of the last door choice as independent of their earlier information. Again, I think it is a human logic flaw, but I would love a study that showed different languages or cultures approaching this problem differently!