With a group of trainers who are also magicians (Ken Bellemare, Mark Isabella, Jeff Lefton, Dimis Michaelides, and Tracy Tagliati), I am writing a book on magic for trainers. Among other things, the book emphasizes how easy it is to misdirect people's attention and to lead them on to fool themselves.
How uses a card trick to highlight the limitations of observation as a data-collection technique.
Perform a card trick in which a randomly selected card apparently appears at a randomly selected number. Ask teams of participants to observe your presentation and try to figure out how the effect was achieved.
To explore the limits of observation as a data-collection technique.
Four or more. Best group size is 10 to 30.
15 minutes for the activity. 10 to 20 minutes for debriefing.
A deck of playing cards.
This activity is designed around a card trick. It is a self-working trick, meaning that you don't have to practice any sneaky sleight-of-hand. However, you do need a lot of practice to become fluent with the moves and the patter. Read through the instructions with a deck of cards in your hand.
Introduce the activity. Explain that you are going to conduct a psychological experiment that involves an ordinary deck of regular playing cards. Tell the participants to carefully observe what you are doing and to take detailed notes on what they see.
Organize participants into teams. If you have more than six participants, organize them into teams of three to six participants each. Tell the members of each team to talk among themselves and distribute the responsibilities for observing different aspects of your performance.
Shuffle the deck. Give a deck of playing cards to a participant. Ask her to shuffle the cards to mix them thoroughly.
Bring the joker to the bottom of the deck. Take the shuffled deck of cards from the participant and say, “I need to locate the joker.”. Turn the deck face up and hold it close to you. Thumb through the cards looking for the joker. Quickly memorize the card just before the joker (the face up card on top of the joker). Remove the cards above the joker and place them below the rest of the deck. This ensures that the card you memorized is at the bottom of the face-up deck.
Call attention to the joker. Show the joker on top of the face-up deck. Explain that when you turn the deck face down, the joker will be at the bottom of the deck. Turn the deck face down. (The joker has no importance except to give you a chance to surreptitiously memorize the card that is now at the top of the face-down deck.)
Give the deck a shallow cut. Place the deck face down on the table. Ask a participant to cut the deck about a third of the way down. Explain that she is to take a packet of the cards from the top of the deck. Ask her to turn this packet over (so that the cards are facing up) and place it on the top of the other cards. (Here's the current status of the cards: A small packet of cards are face up on top of the deck. The remaining cards are face down.)
Cut the deck deeper. Now ask another participant to cut the deck about half way down so that this cut is deeper than the previous cut. Ask the participant to turn over this packet of cards and place it on top of the other cards.
Look at a random card. Ask another participant to go through the cards that are face up, remove them, put this packet aside, and look at the first face down card. Turn your head away and ask the participant not to let you see the card but to show it to the others. Explain that the deck was shuffled and cut twice to ensure that a random card was selected. (Actually, the selected card is the card you memorized.)
Hide the card. Ask the participant to bury the selected card somewhere in the middle of the face-down part of the deck and replace the other cards, turning them face down. Ask another participant to take the deck and shuffle it thoroughly.
Locate the selected card. Take the deck and proclaim that you are going to find the selected card. Ask all participants to visualize the selected card. Turn the deck face up, hold it close to your face, run through the cards, and arrange it so the selected card is at the bottom of the face-up deck.
Confess your failure. Square the cards and show the top face-up card on top of the deck. Ask the participants, “This is not the selected card, is it?” When they say “No” turn the deck face down and confess that your psychic powers have deserted you. Place the deck on the table.
Ask for a number. Ask a participant for a random number between 10 and 20. When you get a number (let's say, 17) tell the participant that she can change her mind if she wants to. Let the participant announce her final choice of a number.
Count off the number of cards. Take the deck of cards and hold it face down. Count to the selected number, one number at a time, this way: Count “one” and place the top card of the deck on the table, face down. Count “two” and place the next card on top of the previous card on the table. Continue counting this way, placing cards on top of each other until you come to the selected number. Place this card face down on top of the packet.
Recap the process. Briefly recall what happened so far: You had the deck of cards shuffled. You had the deck cut twice to select a random card. This card was buried in the deck. The deck was shuffled. You failed to locate the selected card. You are now utilizing advanced telepathic techniques by asking for a random number and counting down to the number.
Show the selected card. Ask participants for the name of the selected card. Turn the face-down packet over to reveal the selected card. Apparently, the selected card is at the random number.
Assign teamwork. Ask participants to work with the other members of their team to figure out how you produced the magical effect. Encourage them to share their observations to compare their notes. Announce a suitable time limit. If participants ask you questions or demand an encore performance, politely tell them to work with what they have already observed.
Ask teams to report their findings. Select one of the teams and ask for its explanation of what happened and how it happened. At the end of this team's explanation, ask the other teams to add their observations and hypotheses.
Give your explanation. Do the trick again, pausing at each step to explain your secret moves. Show how you brought a memorized card to the top of the deck while bringing the joker to the bottom. Work through the two cuts and demonstrate how it left the memorized card as the top face down card. Explain how you brought the selected card back to the top and how it apparently ended up at a randomly selected number.
Conduct a debriefing discussion with questions like these:
- Observation is considered to be the most objective and effective way to collect performance data. After experiencing this activity, what is your current opinion about observation and its limitations?
- How did you divide up the task of observing the activity? How could you have improved your team's observation technique?
- Which of my activities misled you?
- What you observe is frequently shaped by your beliefs and assumptions. What assumptions misled you?
- A glib explanation of card tricks is that the hand is quicker than the eye. Was that one of your hypotheses?
- Since you now know that the trick does not involve any sleight of hand, do you feel that you are ready to perform it for your friends? If you are not ready, what else is needed?
- Would a video recording of the activity make it easier for you to figure out this process? How would you analyze such a video recording?
- Can you come up with examples of how people sometime miss critical elements in their observation?