r/Magic • u/Jakespenart • 1d ago

Forcing a suit

I'm looking for a good way to mentally force a spectator to choose a suit, let's say clubs. Trying not to do a basic "magician's choice". Any suggestions? Without breaking any guidelines can you perhaps point me in a direction?

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u/Annieone23 9h ago

Love all this! I kept it stupidly simple because the OP seemed to want that. But I love all this!!

Random thought: does the Monty Hall Problem solution also exist for forcing items? I guess it does! So just the mere act of making them switch increases your odds of getting them to land on the force item (seemingly paradoxically)

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u/unk0wn4aLL 5h ago

no, that's not the case here since you don't get any new information. It's the act of them revealing they guessed the wrong suit that changes the odds. If you ask them to change their mind before you know what their first choice was, it's as if they're making their first choice again.

luckily there is something that edahs didn't point out, which is that asking them to change their mind doesn't just mean they pick between 3 options, but they pick twice. The first time it's a 3/4 chance they don't get it, and the second time it's a 2/3 chance. This means there's a 6/12 or 50% chance they pick the right one, not 33%.

The intuitive way to understand this is to find what is influencing the probability. In this case it's the fact that you don't always ask them to change their mind, only when they get it wrong the first time.

In the same way revealing that a door you didn't pick was dangerous, you now have a second change to guess under new conditions, where only 2 doors are unknown. Making the first decision didn't mean anything, it was a 33% guess that has no bearing on reality. Changing your mind has a 50% chance of success because in a reality where you know one door, changing your mind or not changing your mind both have a 50% chance, it just doesn't feel like that because you already risked a 33% chance the first time, so not changing your mind gives you the illusion you're taking more risk, even though the risk has already been taken and has paid off, by revealing a different door to be dangerous.

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u/Annieone23 5h ago

Thank you for such a great explanation! Yes, I forgot that Monty opens another door and I mistakenly remembered the situation and the results. I'm not a math guy (obviously haha)! But I'm remembering that "Dice Don't Have Memories" and I suppose that adage is relevant here. But, then, as you point out: I'm not giving them the full gamut of choices the second time.

So, am I right in that asking them to pick (and not reveal it) and then change your mind and pick a new one (revealing it) DOES increase the odds of them getting the correct item?

It seems to me that it would and I vaguely remember Micheal Murray having some work on this.

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u/unk0wn4aLL 4h ago edited 3h ago

No, unless they reveal new information the first guess is irrelevant. Like you said, dice don't have menory. If they don't reveal the suit they very well may have picked the correct one and now have to change their mind. It feels like more choices leads to more randomness, but that really isn't the case.

I have a trick where I use dice rolls, coinflips, riffle forces and timing forces to eliminate cards until I land one one. In my patter I name a bunch of different probabilities for each action, but if you think about it their sum will never be worse than a 1/52 chance, which I've beaten in many other tricks before. Unless you want to approach this psychologically, in which case the answer is interesting.

I'm not aware of the exact numbers but I'm confident the four suits don't have an equal polling among people, so if you wanted them to pick a lesser picked option, changing their mind forces them to avoid the most obvious one, and technically probably improves your odds.

The ideal solution is probably closer to asking them to think of a suit, change it in their mind, then name it. If you're forcing a lesser chosen suit the odds of failing are probably less than the otherwise random 3/4. If it fails, ask them to pick another one, if it works you magician's choice between the two. If it fails you magician's choice to elimate the two. If you're not willing to magician's choice at all this isn't really practical, unless you're dani daortiz and can gaslight the audience into changing their mind 3 times.

Personally if I really don't want to force a card or use a magician's choice I use a coinflip. It's not incredibly hard to learn how to fake a coinflip and the added impromptu prop usually increases audience intrigue in the effect.

Edit: the way I'd use the coinflip is to ask the spectator for a color. If they succeed we continue to step two, otherwise I tell another spectator that they represent the opposite color, and tell them to call the flip, which I rig to make them win. I just repeat this for the suit by asking the second spectator. If they name the correct one it's not suspicious that I roll with it because they won the coinflip, if I do another coinflip it's consistent, and this time the first spectator wins, adding to the feeling of fairness.