Zener cards

Zener cards

Zener cards are cards used to conduct experiments for extra-sensory perception (ESP), most often clairvoyance. Perceptual psychologist Karl Zener designed the cards in the early 1930s for experiments conducted with his colleague, parapsychologist J. B. Rhine.^[1]

Design

Originally, tests for ESP were conducted using a standard deck of playing cards. However, there are many confounding variables involved with this methodology. When this methodology is used, a participant is only credited a correct prediction for guessing both the number and suit of the card. This means that the chance of correctly guessing a card becomes a lot lower, and there is a lot of ambiguity involved with statistical analysis. Another problem with using playing cards is that many people will have a preference for a particular card, number or suit (Irwin 1999) and will constantly suggest that as their prediction for the next card that will appear. This led to the development of a set of cards known as Zener cards, invented by Karl Zener.

There are just five different Zener cards: a hollow circle (one curve), a Greek cross (two lines), three vertical wavy lines (or "waves"), a hollow square (four lines), and a hollow five-pointed star. There are 25 cards in a pack, five of each design.

When Zener cards were first used, they were made out of a fairly thin translucent white paper. Several subjects or groups of subjects scored very highly until it was discovered that they had often been able to see the symbols through the backs of the cards.^[2] A redesign made it impossible to see the designs through the cards under any conditions. A subsequent deck featured an illustration of a building at Duke University on its reverse side, but the use of a non-symmetric reverse design allowed the deck to be exploited as a one-way deck.

Use in experiments

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In a test for clairvoyance, the person conducting the test (the experimenter) picks up a card in a shuffled pack, observes the symbol on the card, and records the answer of the person being tested for extra sensory perception, who must correctly determine which of the five designs is on the card in question. The experimenter continues until all the cards in the pack have been tested.

Third parties may oversee or videotape an experiment to make sure it is conducted fairly. While it is especially important to ensure that the subject cannot see any cards and does not receive any vocal or visual clues from the experimenter, other methods of cheating are possible. To this end, physical separators may be placed between the experimenter and the subject. As with other ESP tests, experiments with Zener cards have used elaborate methods to keep the subject from seeing the cards or the experimenter, sometimes placing the subject in a separate room.

If the subject is informed during the test that specific guesses were correct or incorrect, card counting can increase their accuracy; also, poor shuffling methods can make the order of cards in the deck easier to predict.^[2] In his experiments, Rhine first shuffled the cards by hand but later decided to use a machine for shuffling.

Online variations of Zener card tests currently exist on the internet. If properly constructed, tests of this nature can circumvent the issues of bias and cheating common to standard Zener card tests. One such online system, the Anima Project^[3], gathers user results into a master database which is then analyzed using a variety of statistical techniques.

Although Zener cards are usually used to test for clairvoyance, they may also be used to test for telepathy, in which case one subject will draw a card and attempt to mentally project the image on it to the mind of another subject. Here, the statistical tendency of the receiver to report a specific design must be taken into account — for example, they might tend to report receiving an image of a square more than other images — so the deck used must contain an equal number of cards of each design.

Statistics

If the null-hypothesis (no psychic ability) is assumed and each card selected for testing is chosen in a truly random fashion, a user's success ratio is expected to approach 20% (1 hit per 5 trials) as their number of trials increases. The further the observed scenario is from the expected scenario, the more cause for believing the null-hypothesis is not true (the results are not simply due to chance).

Use in Popular Culture

• In the Cult 1960s series 'The Prisoner' Zener cards are featured in the episode 'The Schitzoid Man' No. 6 practices them with another prisoner with whom he has a telepathic link. Later he uses this in attempt to prove his identity.
• The Hawklords track Psi Power released in 1978 features the lines:

'When I was a kid in school they showed me pictures on a card Then they sent them from a locked and bolted room. I had to fake that it as hard. Circle, square, triangle, waves - I saw then crystal clear by the hour But all I said was can I please take a rest. Didn't want them to know I was possessed With Psi Power.'

• In the 1984 film Ghostbusters, Peter Venkman conducts an experiment on ESP using Zener cards and punishment through electric shocks.
• In the Game Boy Advance game Mario Tennis: Power Tour, the Zener cards are used in the Training Center for PS Training in Level 5 offensive (referred to as 5A in the game) training for ESP.
• In the 2008 DS game The World Ends With You, Shiki's combo finishers and Fusion cards consist of the Zener cards.
• In the film Super High Me, Doug Benson takes a test using the Zener cards in an attempt find out if he is more susceptible to extrasensory perception while under the intoxication of marijuana, or sober.
• In the card game Killer Bunnies: Quest for the Magic Carrot, the Zener Cards appear on the level 20 weapon card Psychic Waves; however, the silhouette of a bunny head is grouped along with the Zener cards.
• In the Heroes Season 3 Volume 4 Episode "1961", Doctor Chandra Suresh is seen showing some Zener cards to Angela Petrelli, who correctly answers them all, due to her ability of precognitive dreaming.
• These cards appear in the 2000 movie "The Gift", starring Cate Blanchett as a psychic fortune-teller who uses them to "read" for people and trigger her clairvoyant visions.

References

• Irwin, 1999, p. 1

External links

• Statistical analysis of precognition/clairvoyance involving online Zener card test
• Zener card test (JRE download is required)
• Zener Cards Online Test