Two colleagues at Duke University decided to collaborate on an experiment in the 1930s to test ESP (Extra Sensory Perception). Simply put, Extra Sensory Perception is the ability to perceive events separate from oneself without using any physical senses. Perceptual psychologist Karl Zener and parapsychologist J.B. Rhine developed the experiement where cards would be held up in front of a subject and they were required to guess what was on the card. The percentage of correct “hits” would then be recorded and whether or not the subject had ESP would be determined by the percentage of correct guess in relation to the number of cards guessed.
Regular playing cards were used in the first phase of experimentation but were quickly deemed inadequate. There were too many variations of the cards and subjects tended to guess their favorite suit rather than what was actually on the card. Zener and Rhine agreed that choosing 5 simple designs in one color would produce more desirable results. The five symbols are the hollowed ring, the hollowed rectangle, the Greek cross, the hollowed 5 pointed star and 3 vertical wavy lines. The deck included 25 cards, 5 cards of every symbol. Hence, the Zener cards were born.
The associates made many errors in conducting the tests in the beginning, many of which were centered around the area of avoiding cheating. The first experiments were conducted with Zener cards printed on translucent paper with ink bleeds and subjects were permitted to hold the cards. The percentage of correct guesses was incredible and it is said that Rhine became very excited about the results. Some criticism about the experiment made them review how they conducted their tests, and changes were immediately made.
Dr. Venkman demonstrating the wrong way to conduct an ESP test.
Scene from 1984 movie Ghostbusters
Changes to the testing method were in constant evolution so that cheating was not possible. Zener and Rhine’s final method was having the subject in a room in one building and the tester in a room in a completely other building. Another important adjustment in the testing was that the subject would not know what guess were right or wrong. Conveying whether a
Scene from the movie The Gift. Cate Blanchette plays a
psychic who uses Zener Cards to give readings.
guess was correct or not, whether by verbally telling them or indicating it was a facial expression, gave the subject valuable information about how many cards of a certain symbol were left in the deck. Once all safeguards against cheating was implemented, the percentage of hits plummetted. Overall, any percentage over the 20%, with the number of guesses taken into consideration, was concluded that something other than chance was causing the success.
Many believe that the Zener Card experiments were never able to successfully prove ESP, but they have definitely become synonymous with testing psychic abilities. Today there are several websites offering free Zener Card testing. Check out some of the links below! You may be more psychic than you think!
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