We may receive a commission for purchases made by using the affiliate/partner links in this post at no additional cost to you. Thank you for helping to support our podcast!

Karl Zener tried for years to remove his name from the cards that would forever be associated with ESP testing. In this episode of Homespun Haints, we go into the history of these strange cards and talk in-depth about the lengthy (and oft hilarious) research that went into psychical phenomena at Duke University during the 20th century.

AI-generated transcript available upon request.

What are Zener cards anyway?

Zener cards have five designs: a cross, a circle, a square, a star, and three wavy lines. A deck of Zener cards has five cards of each design, so twenty-five cards in total. These cards were invented by Duke professor and behavioral psychologist Dr. Karl Zener to aid parapsychologist J. B. Rhine in Rhine’s psychic research on ESP.

what are zener cards?
The five cards present in a Zener card deck. Photo by Aida Servi / stock.adobe.com

Who was Joseph Banks Rhine?

Dr. J. B. Rhine grew up as a Midwestern Christian farm boy. Originally, he wanted to go to divinity school. but his wife talked him into studying science instead by saying, “it’s the wave of the future, Joseph.” So he and his wife moved to the city and they started studying botany. As their interest in the natural world grew, they began to wonder how they could use scientific thinking to answer “life’s big questions” that they had pondered in their very religious upbringing.

Rhine (left) and Zener (right, the man who invented Zener cards)
J.B. Rhine (left) and Karl Zener (right).
Zener would spend decades trying to disassociate himself from the eponymous cards he created to aid Rhine in ESP research.

Eventually, they moved into studying psychic abilities, which Rhine coined as “Extrasensory Perception.” He approached a colleague of his, Karl Zener, and asked him to develop the cards he used in testing. For the next three decades, Rhine tested thousands of students for psychic abilities in his Duke University lab with funding from private donors and the U.S. Government. The public grew so interested in his experiments that even astronaut Edgar Mitchell agreed to conduct ESP experiments for him while in space aboard the Apollo 14.

Edgar Mitchell, who conducted ESP experiments using a codified Zener card table while aboard the Apollo 14. Photo courtesy of NASA.

Listen to the episode to learn more

For the real scoop and in-depth history of psychical research and J. B.Rhine, listen to our episode! And have a spooky day!