Zener Cards - Use in Experiments

Use in Experiments

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 his or her accuracy; also, poor shuffling methods can make the order of cards in the deck easier to predict. 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, 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, he or she 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.