E.S.S.D. -- Two card monte

E.S.S.D. -- Experiments someone (else) should do

This is the first in my list of experiments I think someone should do. The idea is that one of my unemployed friends might see this, think "hey, that'd be a neat project," and then do it, simultaneously satisfying my curiosity and turning that person into a slightly useful member of society. Either that, or somebody looking for a neat science fair project might be looking for something original. As far as I know, the answers to the E.S.S.D. questions will be unknown, or I won't be sure if the method will work.

Title: Two card monte
Field: psychology
Difficulty: as hard as you want
Importance to science: probably none

Introduction: Here's one of my favourite magic tricks. I have two cards.


One is the 3 of spades.

The other is the queen of hearts.

Now, I show you these cards a couple of times, then slowly take the 3 and put it behind my back. I ask you what card went behind my back. You, of course, say the 3, but when I take it out, it's the queen. And I show you again that I have only two cards.

If you look closely at those pictures, you'll probably figure out what I'm doing. But here's the thing. To some people, I can do this trick 40 times, and they won't get it. They just get increasingly baffled and amazed. Other people, maybe 1 in 50, pick up the trick right away.

So what causes some people to figure it out immediately, while others never do? I have done this trick for hundreds of people. Maybe a thousand, or two thousand. And my observation is that the people who figure it out are most often "grabby" people. Small children, mostly, but also adults who have an impulse to reach out and grab the cards as soon as I pull them out. Most people aren't rude enough to actually grab the cards, but I can tell immediately by the twitch of a hand that this trick will probably not work on that person.

So if you haven't figured it out yet, look at the first picture again, and imagine yourself touching the 3. Then look at the second picture.

So that's the experiment. Does actually touching the object change how the viewer perceives it? Does just the thought of touching it change it? You could show this trick to three samples of people who have never seen it. One group is instructed to touch the card before they are turned over. One is instructed to think about touching it. One, the control group, gets no instructions. (Maybe a post-trick questionnaire could separate those in the control group who thought about touching it from those who didn't.) You'd need a consistent way of presenting the trick... a robot or a video. Maybe do it five times, and see if it takes certain groups longer to figure it out. Control for age, sex, et cetera.

There could be some genuine psychological principles in this. But at the very least, it'd make for a difficult experimental design that would be fun to do. There are all sorts of possibilities for playing with statistics. And you'd get to trick a lot of people, all in the name of science.

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