How do magic tricks work in the mind?To answer this, we first had to study the tools used by magicians:playing cards.
Specifically, we measured five factors of cardsthat may be relevant to magic tricks:
- visibility,how well a card is detected among other cards;
- memorability,how well it is remembered;
- likability,how much it is liked;
- verbal accessibility,how likely it is chosen when asked to name a card; and
- visual accessibility,how likely it is chosen when asked to visualise a card.
We describe the methods and conclusions of each study below. Average data for each playing card, the raw data, and the paperare also available.
Visibility:How well can people detect particular cards?
We showed 96 people a fast series of playing cards while they triedto detect a particular card in the series.
People detected simpler and distinct cards better. They detectedthe Ace of Spades better than other Aces, and Aces better thannumber cards.
Suit had no effect on how well people detected cards. However,within number cards, people seemed more likely to declare Spadesabsent.
People also seemed particularly likely to report seeing the Sixof Hearts and Six of Diamonds, whether or not they appeared.
Memorability:How well can people remember particular cards?
We showed the same 96 people a slow series of cards, then theytried to remember whether a particular card appeared in theseries.
Similar to the visibility study, people remembered the Ace of Spadesbetter than other Aces, and Aces better than number cards.
People could remember different number cards equally well, butseemed more likely to declare the card absent as the numberincreased.
Likability:How much do people like particular cards?
We showed 48 people two cards side-by-side and asked which onethey liked more.
People showed strong preferences for particular cards. Theypreferred the Ace of Spades over other Aces on average, Aces overnumber cards, and face cards over number cards.
They usually seemed to prefer Spades and Hearts more than Clubsand Diamonds.
Women seemed to prefer lower-valued cards (Twos and Threes) morethan men did.
Verbal accessibility:Which cards do people verbally choose the most?
In a separate experiment, we asked 667 people to name a playingcard.
We saw the same pattern of results as in the Likability study.People chose the Ace of Spades more than other Aces, and Aces andface cards more than number cards.
More than half of the people chose one of four cards: the Ace ofSpades, Queen of Hearts, Ace of Hearts, and King of Hearts.
For number cards, people seemed to name Threes and Sevens the most.
Women seemed more likely to name the King of Hearts, and men theQueen of Hearts.
People rarely chose middle-valued number cards. Of 423 validresponses, nobody chose the Four of Spades, Five of Clubs, Five ofDiamonds, Six of Clubs, or Six of Diamonds.
Many people misunderstood the question. Some people named cardgames, and a few literally named a card ("Joe").
Visual accessibility:Which cards do people visually choose the most?
In another experiment, we asked 700 people to visualise a playingcard, then tell us what it is.
We saw the same pattern of results as in the Verbal Accessibilitystudy.
However, people seemed more likely to choose the Ace of Heartswhen asked to visualise one rather than name one.
People chose every card except the Five of Spades.
Some people mentioned different kinds of cards ("business card"),others told us what a playing card is ("cardstock laminated withplastic").
Relationships between factors
We also looked at whether any of these five factors related toeach other. Some of them did.
People would more likely misreport remembering accessible cards.When asked, in the Memorability study, whether they remembered acard, people would often misreport seeing accessible cards like theAce of Spades or Queen of Hearts.
People also liked, verbally chose, and visually chose thesame kinds of cards.
Future directions
The next step is to apply this knowledge of cards to magic tricks,to better understand how magic works in the mind.
