Nine Card Polygraph

Many magicians have applied the Lie Speller card plot to "The Nine Card Problem" by Jim Steinmeyer. "Nine Card Polygraph" is my attempt to do the same, but with a different selection process where the spectator can simply think of any of the nine cards in the packet.

The polygraph, often wrongly referred to as a lie detector, has a controversial past. Nowadays, most criminologists consider this technology pseudoscience. However, this does not necessarily mean that the machine is ineffective. In fact, if a suspect believes the polygraph can accurately detect whether a person is lying or telling the truth, its effectiveness is enhanced. The presentation for this trick uses this fascinating fact as a hook for the magic that unfolds.

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On This Page

Effect
Background & Credits
Requirements & Preparation
Method & Presentation
Performance Tips & Additional Ideas
Afterthoughts

Effect

In this magic trick, the performer makes the preposterous claim that they can use playing cards to detect whether someone is lying or telling the truth. To begin, the performer removes a few cards from a shuffled deck and asks a spectator, playing the part of a criminal being interrogated, to mentally select one of the cards and then thoroughly mix the packet.

After calibrating the machine with a few test questions, the performer asks the participant what card they are thinking of. The participant can either lie or tell the truth. The performer then "inputs" the answers into the machine by dealing a card to the table for each letter in the name of the thought-of card. Once each word is spelt, the remaining cards are dropped on top.

The performer spells out the word "TRUTH" by dealing one card to the table for each letter in the word. Finally, the last card dealt is turned over and revealed to be the very same card the participant is thinking of!

Background & Credits

This trick is based on "The Nine Card Problem" by Jim Steinmeyer, which was first published in MAGIC Magazine (May 1993, page 56). The trick was reprinted in Jim's book Impuzzibilities in 2002.

The underlying principle is related to the trick "Remote Control", also created by Jim Steinmeyer and published in The New Invocation (No. 43) in February 1988. While "Remote Control" requires eighteen cards, not nine, it uses a similar method.

A much earlier application of the same principle can be found in Abbott's Anthology of Card Magic Volume Three, compiled by Gordon Miller. It is used in a trick using the whole pack called "Miracle Mix-Up" by Jack Yates (page 58). Initially, Jack sold the trick as a manuscript in 1953.

The "deal or switch" mixing procedure, also known as the "Swindle Shuffle", was devised by Paul Curry and first published as part of a trick of his called "A Swindle of Sorts" in his book Paul Curry Presents, first published in 1974.

The trick relies on the Redistribution Principle, which involves the systematic rearrangement of cards into various groups to accurately determine the location of a mental selection. The principle, made famous by The Twenty-One Card Trick, dates back to at least the seventeenth century.

Requirements & Preparation

All you need to perform this card trick is a regular deck of playing cards.

Method & Presentation

Hand the cards to Paige and ask her to shuffle them thoroughly before giving them a cut.

Take the deck back and deal one card to the table for each letter in the word "POLYGRAPH", spelling out the word as you do so. Explain to your audience that this small packet of cards will act as a lie detector. Dealing the cards in this way avoids the need to count them. Because the method is mathematical, it is advisable to avoid mentioning numbers during the trick.

Hand the nine-card packet to Paige. Ask her to mix the cards, look at them and remember one. Once she's done this, tell her to give them another quick mix.

To begin, take the cards and deal them into three equal piles. After you have done this, state, "I need to calibrate the lie detector by asking you a few test questions. You must answer the first three truthfully." Pick up the pile on your far right, spread out the three cards, and inquire, "Can you see your card?" Keep Paige's response in mind. Repeat the same process with the other two piles. You will receive two negative and one positive response. The pile that receives the positive response to the question will contain the selected card.

Next, take the pile that contains the chosen card and shuffle it. Then, ask Paige to select one of the remaining piles by pointing to it. Place the three cards you're holding on top of the pile indicated by Paige. Finally, take the remaining three-card pile and put it on top of all. While your participant has a free choice, this decision is inconsequential because the pile with the chosen card in it will always end up sandwiched between the other two piles. Therefore, the selected card is guaranteed to be fourth, fifth or sixth from the top of the assembled packet.

Perform a Swindle Shuffle to apparently mix the packet. All this shuffle does, however, is reverse the order of the cards. Consequently, the chosen card will still be fourth, fifth or sixth from the top of the packet.

Deal the cards into three equal piles again and then say, "This time, I want you to lie each time I ask you a question." Pick up each pile in turn and say, "Do you see your card?" This time, remeber which pile receives a negative response because this will be the pile that contains the thought-of selection. The middle card of this pile will always be the chosen card.

Take the pile containing the chosen card and mix the cards so that the selected card ends up on top. Then, ask Paige to pick one pile and drop the cards onto it. Place the other pile on top of all. The chosen card will always end up fourth from the top of the assembled packet.

Perform another Swindle Shuffle. The selection will now be sixth from the top of the packet.

Explain to Paige that you will ask her two more questions; for each, she can decide to lie or tell the truth. Spell the word "THE", and for each letter in the word, deal a card to the table. Drop the cards remaining in your hand on top of the pile on the table.

Next, say, "What is the value of your card?" Let's assume Paige says her card is a Queen. Spell "QUEEN", dealing one card for each letter into a single pile. Drop the cards left in your hand on top. It doesn't make any difference if Paige lies or tells the truth. Her chosen card will always end up third from the bottom of the pile.

Pick up the cards and say, "Every card has the same middle name: 'of'!" Deal two cards to the table as you spell "OF". Drop the remainder on top, as before.

Turn to Paige and say, "Now, what is the suit of your card? Clubs, Hearts, Spades or Diamonds?" If, for example, she says "hearts", spell out the word and deal one card to the table for each letter. Regardless of what suit is named, the chosen card will always end up fifth from the top of the pile.

Finally, pick up the pile and spell the word "TRUTH", again dealing one card for each letter of the word into a pile. When you reach the fifth card, flick it with your thumb as you spell the last letter of the word "TRUTH". Look at Paige and say, "Please tell the truth. What is the name of the card you're merely thinking of?" Slowly turn the card in your hand face up to reveal the chosen card.

Performance Tips & Additional Ideas

It is a good idea to start the trick by discussing the unreliability of polygraph tests. Interestingly, if someone believes that the polygraph is accurate, its reliability actually increases. Similarly, explain to your audience that if they believe in the effectiveness of using a small packet of playing cards as a lie detector, it will actually work!

Performing the lie detector trick can be dangerous as it may unintentionally reinforce the myth of the accuracy of polygraph tests. Scientific and government bodies agree that polygraphs are highly inaccurate, easily manipulated by countermeasures, and are not a reliable means of assessing truthfulness. Therefore, it is recommended to include this information in the introduction of the trick to generate interest in the routine while avoiding promoting unhelpful misinformation about polygraphs and lie detection.

You can perform this trick with twenty-seven cards, entirely relying on the Redistribution Principle. Deal the cards into three piles consisting of nine cards each. Ask your participant to choose one pile, look through it, and memorise a card. Then, deal out the cards again and ask them to tell the truth if they see their chosen card. Pick up each pile in turn and spread the cards so that your volunteer can look for their card. Gather the cards up so that the pile containing the chosen card is in between the other two piles. 

Deal out the cards once more, and tell your audience to tell the truth this time. Once again, place the pile containing the selected card in between the other two piles. For the third and final round, tell your helper that they can lie or tell the truth; it is entirely up to them. This time, the chosen card will always be the fifth card down in the middle pile. Therefore, you can tell your participant when you think that they're being truthful or dishonest. 

Pick up the pile containing the chosen card, then thumb the top card to the bottom as if you're cutting the deck. Proceed by performing "Nine Card Polygraph" as described above. Alternatively, you can spell "TRUTH", dealing one card for each letter of the word into a pile to arrive directly at the thought-of card. Experienced magicians will recognise this method as the same one used in The Twenty-One Card Trick.

Afterthoughts

This is a combination of The Nine Card Trick, a variation of The Twenty-One Card Trick using only nine cards, and Jim Steinmeyer's "The Nine Card Problem". Although it may not excite experienced card magicians, it significantly strengthens the selection process of "The Nine Card Problem" by allowing any of the nine cards to be mentally selected. The use of a lie detector presentation justifies the repeated dealing procedure, which only involves nine cards and doesn't take long to complete.