4 ms·

I saw an interesting perspective on the Monty Hall problem from judegomila earlier this month - https://twitter.com/judegomila/status/1183425802399969282 https

by teej 7y ago

I saw an interesting perspective on the Monty Hall problem from judegomila earlier this month - https://twitter.com/judegomila/status/1183425802399969282 https://twitter.com/judegomila/status/1183425802399969282 "Your brain will compute monty hall problem in fast casual causal mode AND/OR compute slow mode formally for the exact answer. Probability predictions that accurately map reduce to efficient intuitive representations in our brain dictate direction in our evolutionary biology." "[since] we don't solve the monty hall problem effectively with our intuition, an evolving life form would be poor at resource collection from such problem sets without knowledge of axiom representation and formal probability."

godson_drafty 7y ago
"Sire. Shall we hunt in the valley, in the forest, or in the mountains?" We shall hunt in the forest. "Sire! Our scouts have just returned from the mountain. They report that the herds are not there at the present time! Shall we try the valley, or continue on to the forest?" A) Stick to the plan, and hunt in the forest B) Hunt in the valley instead
- greenshackle2 7y ago
  The Monty Hall paradox hinges on the fact that the host knows in advance where the car is. If your scouts don't know where the herds are, but just picked an area at random to recon, then it is a different problem, and switching makes no difference.
  - bzbz 7y ago
    And I think you stumbled upon the crux of the problem. I think we have a hard time grasping the fact that Monty not just picks one of the other two doors, but also specifically guarantees that it won't be the winning door. Without that guarantee, it makes no difference. Additionally, there are not many situations in real life that would replicate the conditions of that guarantee. So our "intuition" is simply geared towards situations where an actor can't read our thoughts (door pre-selection) before we act them out, and in such a scenario, pre-selecting/switching selection of doors doesn't matter.
  - kortilla 7y ago
    But it doesn’t depend on Monty knowing ahead of time. Monty can learn after you pick, but before he reveals (to be sure he doesn’t reveal a car). The scouts can depart after you’ve chosen the valley, find nothing in the mountain, give that information to you, and you should still switch, even if the scouts didn’t confirm where they are. Monty(or the scouts), knowing if your original pick was right has no impact. The critical piece is that they are forced to reveal to you a bad choice. 2/3 times it’s the only bad choice to reveal because you’ve picked the other.
    - dllthomas 7y ago
      If the herds might have been in the valley and don't happen to be, you learn something. Your odds rise from 1/3 to 1/2. If the scouts know where the herds are and specifically checked the valley because the herds weren't there, you learn more - your odds rise to 2/3. But not as much as if they just told you where the herds are, so we're back to it being an unlikely scenario.
      - kortilla 7y ago
        Nope. Monty still reveals a door even if your planned pick was correct. The entire gain in odds is predicated on Monty being forced to reveal a bad choice after you have chosen. Monty knowing ahead of time has absolutely no impact on the outcome.
        dllthomas 7y ago
        Knowing that Monty could not have revealed the car (vs happened not to) has an impact. If you are objecting to how I described that, in terms of who knows what when, then you may be right and I probably could have been more precise. But if you are disagreeing that scouts sent to investigate an area and return an answer (which this time happens to be negative) differs materially from the original question then you are wrong.
        kortilla 7y ago
        > Knowing that Monty could not have revealed the car (vs happened not to) has an impact. Nope, it does not. The fact that he revealed a dud is what matters. The notion of him maybe revealing a car is senseless anyway because you would just then pick the car or the game would be over.

by teej 7y ago

godson_drafty 7y ago

"Sire. Shall we hunt in the valley, in the forest, or in the mountains?" We shall hunt in the forest. "Sire! Our scouts have just returned from the mountain. They report that the herds are not there at the present time! Shall we try the valley, or continue on to the forest?" A) Stick to the plan, and hunt in the forest B) Hunt in the valley instead

greenshackle2 7y ago
The Monty Hall paradox hinges on the fact that the host knows in advance where the car is. If your scouts don't know where the herds are, but just picked an area at random to recon, then it is a different problem, and switching makes no difference.
- bzbz 7y ago
  And I think you stumbled upon the crux of the problem. I think we have a hard time grasping the fact that Monty not just picks one of the other two doors, but also specifically guarantees that it won't be the winning door. Without that guarantee, it makes no difference. Additionally, there are not many situations in real life that would replicate the conditions of that guarantee. So our "intuition" is simply geared towards situations where an actor can't read our thoughts (door pre-selection) before we act them out, and in such a scenario, pre-selecting/switching selection of doors doesn't matter.
- kortilla 7y ago
  But it doesn’t depend on Monty knowing ahead of time. Monty can learn after you pick, but before he reveals (to be sure he doesn’t reveal a car). The scouts can depart after you’ve chosen the valley, find nothing in the mountain, give that information to you, and you should still switch, even if the scouts didn’t confirm where they are. Monty(or the scouts), knowing if your original pick was right has no impact. The critical piece is that they are forced to reveal to you a bad choice. 2/3 times it’s the only bad choice to reveal because you’ve picked the other.
  - dllthomas 7y ago
    If the herds might have been in the valley and don't happen to be, you learn something. Your odds rise from 1/3 to 1/2. If the scouts know where the herds are and specifically checked the valley because the herds weren't there, you learn more - your odds rise to 2/3. But not as much as if they just told you where the herds are, so we're back to it being an unlikely scenario.
    - kortilla 7y ago
      Nope. Monty still reveals a door even if your planned pick was correct. The entire gain in odds is predicated on Monty being forced to reveal a bad choice after you have chosen. Monty knowing ahead of time has absolutely no impact on the outcome.
      - dllthomas 7y ago
        Knowing that Monty could not have revealed the car (vs happened not to) has an impact. If you are objecting to how I described that, in terms of who knows what when, then you may be right and I probably could have been more precise. But if you are disagreeing that scouts sent to investigate an area and return an answer (which this time happens to be negative) differs materially from the original question then you are wrong.
        kortilla 7y ago
        > Knowing that Monty could not have revealed the car (vs happened not to) has an impact. Nope, it does not. The fact that he revealed a dud is what matters. The notion of him maybe revealing a car is senseless anyway because you would just then pick the car or the game would be over.